The OHIO DEPARTMENT of TRANSPORTATION

Transcription

1 The OHIO DEPARTMENT of TRANSPORTATION

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3 Preface Purpose Many manuals, policies, guides, standards, etc., have been published regarding pavement design and rehabilitation. Many of these have been written using wide ranges of design recommendations (minimums and maximums) since the contents were intended to apply nationally. Furthermore, the Ohio Department of Transportation s pavement design and rehabilitation procedures have been scattered among many different publications, poorly documented or in some cases existed only in the minds of a select few engineers. The purpose of this manual is to bring all the information together in one document, reduce the selection of design variables to those most appropriate for the State of Ohio, to document Ohio s interpretation of various policies and to include design criteria which may be unique to Ohio. Application The pavement engineering concepts described herein are intended for use with all new or reconstruction projects, major and minor rehabilitation projects, and all preventive maintenance projects, which are under the jurisdiction of the Ohio Department of Transportation (ODOT). The information contained in this manual has been taken from and based on the results of the AASHO Road Test, the AASHTO Guide for Design of Pavement Structures, Federal Highway Administration (FHWA) guidelines and technical advisories, various training course manuals, as well as from the experience of the authors. In addition, the application of other studies, experiences, and engineering judgments have been included to fit Ohio's conditions. The pavement design procedures relate the performance of a pavement to its structural design and the loading applied to the pavement. Failure mechanisms derived from poor mix design, poor material quality, or poor construction practices are not addressed in this manual. This manual is neither a textbook nor a substitute for engineering knowledge, experience or judgement. It is intended to provide uniform procedures for implementing design decisions, assure quality and continuity in design of pavements in Ohio, and assure compliance with Federal criteria. The recommendations given are intended to improve pavement performance. Consideration must be given to design standards adopted by city, county, or other local governments when designing pavements under their jurisdiction. Distribution This manual is intended primarily for ODOT personnel who have received training from the Office of Materials Management. It is made available to cities, counties, consultants, etc., to use at their own risk. Preparation The Pavement Design and Rehabilitation Manual has been developed by the Office of Materials Management. Errors or omissions should be reported to the Pavement Design Section of the Office of Materials Management, Ohio Department of Transportation, 1600 West Broad Street, Room 2033, Columbus, Ohio Format and Revisions Updating the manual is intended to be a continuous process and revisions will be issued periodically. Although pages are individually numbered within each section, new pages may be added and identified with letter suffixes after the page number. Figures do not have page numbers but are numbered to coincide with the section number in the text. Figures are located at the end of each section and are printed on colored paper for easy reference. Each page has the latest revision date shown in the lower left hand corner. Revisions will be issued as needed by the Office of Materials Management. The looseleaf format of the manual makes updating a quick and simple task. Users are encouraged to keep their manuals up to date. Manuals may be ordered by contacting the Ohio Department of Transportation, Office of Contracts, P.O. Box 899, Columbus, Ohio , (614) , January 1999 i

4 Pavement Design Approval and Responsibility All pavement design buildups pertaining to roadways designated as Interstates, US Routes, National Highway System (NHS) routes, and State Routes or otherwise under the jurisdiction of the Ohio Department of Transportation must be approved by the Ohio Department of Transportation prior to incorporation into a set of construction plans. Those Agencies, Municipalities, or Consultants seeking pavement design buildup or approval from the Ohio Department of Transportation should make the request through the appropriate ODOT District Office. A formal request for pavement design buildup or approval should include the following: Plan and profile sheets indicating the existing and proposed profile. Typical section templates indicating the pavement and shoulder widths, lane lines and pavement/shoulder cross slopes. All required soils information, including the soil profile and soils reports. Traffic data, certified by the Office of Technical Services, indicating the average daily traffic (ADT) and percentage trucks in the 24-hour count for both the current year and design year. January 1999 ii

5 Glossary of Terms California Bearing Ratio (CBR) - A value obtained by standardized soil testing procedures comparing the load required to penetrate the soil to a standard unit load. Composite Modulus of Subgrade Reaction (K c ) - A value used in rigid pavement design determined by dividing the load on a subgrade by the deflection, corrected for the effect of a base. Concrete Elastic Modulus (E c ) - A measure of the rigidity of a pavement slab and its ability to distribute loads. Contraction Joint - A joint at the ends of a rigid pavement slab to control the location of transverse cracks. Design Serviceability Loss ()PSI) - The change in the serviceability index of a pavement from the time it is constructed to the end of its design life. Design Structural Number (SN) - A regression coefficient derived from an analysis of traffic, soil conditions and environment and which may be converted to thickness of flexible pavement layers using coefficients related to the type of material being used in each layer of the pavement structure. Discount Rate - An economic factor to account for the effects of interest and inflation. Drainage Coefficient - A factor used to modify structural layer coefficients in flexible pavements, or stress in rigid pavements, as a function of how well the pavement structure can handle the effect of water infiltration. Effective Modulus of Subgrade Reaction (K) - The Composite Modulus of Subgrade Reaction modified by Loss of Support. Equivalent Single Axle Load (ESAL) - Truck traffic loading expressed as the number of equivalent 18,000 lb (80 kn) single axle loads. Expansion Joint - A transverse joint located to provide for the expansion of a rigid slab in the longitudinal direction without damage to itself or adjacent slabs. Generally placed near bridges. Functional Characteristics - Qualities of a pavement such as surface smoothness, skid resistance, and non-load related distresses such as block cracking, and oxidation of asphalt pavement surfaces. Functional Classification - The grouping of highways by the character of service they provide. Group Index - A number derived from the gradation, liquid limit and plasticity index of a soil. Life-Cycle Cost Analysis - A process for evaluating the economic worth of a pavement segment by analyzing initial costs and discounted future costs over a defined period. Liquid Limit - The moisture content at which a soil flows like a viscous liquid. Load Transfer Coefficient (J) - A factor used in rigid pavement design to account for the ability of a concrete pavement to distribute load across joints and cracks. Longitudinal Joint - A pavement joint, in the direction of traffic flow, used to control longitudinal cracking on a rigid pavement or the joint formed between adjacent passes of a paver on a flexible pavement. Loss of Support (L s ) - A factor included in the design of rigid pavement to account for the potential loss of support arising from base erosion and/or differential vertical soil movements. Major Rehabilitation - Work performed on a pavement intended to restore structural integrity and functional characteristics. Mean Concrete Modulus of Rupture (S c ) - The flexural strength of concrete derived from a beam test with third point loading. Minor Rehabilitation - Work performed on a pavement intended to restore functional characteristics and protect the structural integrity. Multi-Lane Pavements - Pavements with four or more lanes. Continuous two-way left turn lanes are considered lanes in this definition. January 1999 iii

6 Overall Standard Deviation - A statistical measure to account for the error in the prediction of traffic and pavement performance. Pavement Condition Rating (PCR) - A numerical rating of pavement distresses on a 0 to 100 scale based on visual inspection. A PCR of 100 signifies a perfect pavement with no distress. Pavement Edge (Edge of Pavement) - The intersection of the mainline pavement and the treated shoulder or turf shoulder. Plastic Limit - The minimum moisture content at which the soil acts as a plastic solid. Present Serviceability Index (PSI) - A numerical index which correlates roughness measurements on a scale of 0 to 5. A PSI of 5 indicates an exceptionally smooth pavement. Pressure Relief Joint - Similar to Expansion Joint but placed exclusively near bridges to prevent damage to the bridge. Preventive Maintenance - Work performed on a structurally sound pavement, generally in the form of a surface treatment, intended to preserve the pavement, retard future deterioration, and maintain or improve the functional condition without substantially increasing the structural capacity. Structural Deduct - A part of the Pavement Condition Rating indicating distresses which may be related to the structural integrity of the pavement. Structural Integrity - The ability of a pavement to carry anticipated loading. Structural Layer Coefficient - A measure of the relative ability of a material to function as a structural component of a flexible pavement structure and used to convert a design structural number to actual thickness. Subbase Elastic Modulus - A measure of the ability of a subbase to carry a load. Subgrade Resilient Modulus (M r ) - A measurement of the stress dependency of a subgrade soil, determined by the LTPP P46 test procedure. Terminal Serviceability Index (P t ) - The serviceability index assumed at the end of the pavement design life. Transverse Joint - A pavement joint perpendicular to the centerline alignment of the pavement, designed to control cracking, provide for load transfer, and allow for the contraction and expansion of the pavement. Reliability (R) - A statistical measure of the probability that a section of pavement will meet or exceed the predicted performance. January 1999 iv

7 Reference Documents Circular Number A-94 (Office of Management and Budget ), Appendix C (OMB - Current Revision) Construction and Material Specifications (ODOT - Current Edition) Guide for Design of Pavement Structures (AASHTO ) Highway Engineering Handbook (McGraw-Hill ) Location and Design Manual, Volume Two - Drainage Design (ODOT - Current Revision) Location and Design Manual, Volume Three - Highway Plans (ODOT - Current Revision) Location and Design Manual, Volume Three - Highway Plans, Sample Plan Sheets (ODOT - Current Revisions) Manual of Operation and Use of Dynaflect for Pavement Evaluation (ODOT ) Manual of Procedures for Concrete (ODOT - Current Revision) Manual of Procedures for Earthwork Construction (ODOT - Current Revision) Manual of Procedures for Flexible Pavement Construction (ODOT - Current Revision) Manual of Procedures for Rigid Pavement Practices (ODOT - Current Revision) Pavement Rehabilitation Design Training Course, Participants Manual (ODOT ) Principles of Pavement Design (Wiley-Interscience ) Specifications for Subsurface Investigations (ODOT - Current Revision) Standard Construction Drawings (Location & Design, ODOT - Current Revisions) Verification of the ODOT Overlay Design Procedure (ODOT ) Pavement Condition Rating System (ODOT ) June 1999 v

8 Acknowledgments Principle Writers: Aric A. Morse, P.E. Pavement Engineering Coordinator ODOT Office of Materials Management David W. Miller, P.E. Assistant Pavement Engineer ODOT Office of Materials Management The authors wish to thank the following people for their assistance in writing, reviewing, editing, printing, and distributing this Manual. Without their efforts, this Manual would not have been possible. William L. Christensen, P.E., ODOT Office of Highway Management Thomas B. Culp, P.E., ODOT District Three Karen S. Eitel, ODOT Office of Materials Management Dean A. Focke, P.E., ODOT Office of Planning Donald H. Glosser, P.E., American Concrete Pavement Association Roger L. Green, P.E., ODOT Office of Materials Management Keith D. Herbold, P.E., FHWA Midwest Resource Center Robert T. McQuiston, P.E., FHWA Ohio Division Kimberly M. Mondora, P.E., ODOT District Four David B. Powers, P.E., ODOT Office of Materials Management Russell L. Slonecker, P.E., ODOT District One Clifford Ursich, P.E., Flexible Pavements, Inc. Debbie L. Moreno and everyone at the ODOT Print Shop June 1999 vi

9 Table of Contents 100 Pavement Management Introduction Pavement Condition Rating Present Serviceability Index Project Level Pavement Management and Analysis PCR Historical Trends PCR Performance Equations Pavement Modeling Pavement Design Concepts Introduction Serviceability Initial Serviceability Terminal Serviceability Design Serviceability Loss Traffic Considerations Traffic Loading Calculation of ESAL s ESAL Subgrade Soil Characterization Subgrade Resilient Modulus California Bearing Ratio Group Index Soil Profile Analysis Reliability Overall Standard Deviation Subsurface Pavement Drainage Types of Drainage Systems AASHTO Drainage Coefficient Rigid Pavement Design Procedures & Considerations Introduction Design Parameters Modulus of Rupture Modulus of Elasticity Load Transfer Coefficient Composite Modulus of Subgrade Reaction Loss of Support Effective Modulus of Subgrade Reaction...3-2

10 302 Thickness Determination Ramps and Interchanges Jointing and Shoulder Considerations Transverse Joints Expansion Joints Longitudinal Joints Shoulder Considerations Edge Course Design Intersection Jointing Details Smoothness Specifications Composite Pavement Composite Pavement Design Composite Pavement Typical Section Design Composite Pavement Smoothness Specifications Flexible Pavement Design Procedures & Considerations Introduction Design Parameters Structural Number Determination Ramps and Interchanges Typical Section and Buildup Considerations Typical Section Design Shoulder Buildups Edge Course Design Paved Shoulder Edge Course Design Lift Thickness and Specification Guidelines All Item 446 & 448 Type 1 and Type 2 Courses Superpave Specifications Item 446 & 448 Asphalt Concrete Surface Course, Type 1, PG Items 446 and 448 Asphalt Concrete Surface Course, Type 1H Item 446 Asphalt Concrete Intermediate Course, Type 1, PG Item 446 Asphalt Concrete Intermediate Course, Type 2, PG64-28 & PG Item 448 Asphalt Concrete Intermediate Course, Type 1, PG64-28 & PG Item 448 Asphalt Concrete Intermediate Course, Type 2, PG64-28 & PG Item 301 Bituminous Aggregate Base, PG Item 302 Bituminous Aggregate Base, PG Item 407 Tack Coat Item 408 Prime Coat Smoothness Specifications 4-6

11 500 Pavement Design Procedures for Minor Rehabilitation Introduction Deflection Measuring Equipment Dynaflect Falling Weight Deflectometer Deflection Testing and Analysis General Analysis Factors Affecting Deflections Overlay Design Procedure Introduction Rigid Pavements Flexible Pavements Composite Pavements Minor Rehabilitation Strategies Asphalt Considerations Milling Pavement Repair Reflective Crack Control Concrete Pavement Restoration Geometric Issues Pavement Widening Major Rehabilitation Design Introduction Subgrade Determination Unbonded Concrete Overlay Fractured Slab Techniques Crack & Seat Rubblize & Roll Whitetopping Life-Cycle Cost Analysis Introduction Initial Construction Future Maintenance Introduction Maintenance Schedules Total Cost Discounting...7-4

12 704 Lane Closure Days Results Presentation 7-4 Pavement Design and Selection Process Appendix A Pavement Guidelines for Treatment of High Stress Locations Appendix B Simplified Pavement Designs for Short Projects Appendix C ODOT s PCR Manual Appendix D

13 Table of Contents 100 Pavement Management Introduction Pavement Condition Rating Structural Deduct Present Serviceability Index Project Level Pavement Management and Analysis PCR Historical Trends PCR Performance Equations Pavement Modeling...1-2

14 100 Pavement Management Introduction The movement of people and goods throughout the state, as well as interstate, is primarily dependent upon the transportation network of pavements managed by the Ohio Department of Transportation (ODOT). The management of this vast network is aided by ODOT s Pavement Management System (PMS). ODOT s PMS is a systematic approach that provides various reports regarding the condition of each and every pavement section, as well as the system as a whole. For the purpose of standard pavement analyses, the Pavement Condition Rating (PCR), Present Serviceability Index (PSI), and the Structural Deduct (SD) are all contained within the standard PMS report outputs. Standard PMS reports are available for download. For detailed information regarding the PMS, contact the Office of Technical Services Pavement Condition Rating Pavement Condition Rating (PCR) is based on a visual inspection of the condition of the pavement by trained raters. The rater catalogs pavement distresses in terms of severity and extent, assigns a deduct to each distress, and subtracts the sum of the deducts from 100. A pavement in perfect condition receives a PCR of 100. PCR data is collected annually for all divided and undivided state highways with exception of those located inside corporate limits of municipalities. This Manual includes ODOT s PCR Manual in Appendix D Structural Deduct Structural Deduct (SD) is contained within the PCR, but indicates those distresses which may be related to the structural integrity of the pavement. A structural deduct of 25 or more indicates the pavement section should be considered for major rehabilitation Present Serviceability Index Present Serviceability Index (PSI) is a measure of pavement surface roughness or riding comfort. It is measured on a scale between 0 and 5, with 5 being a perfectly smooth ride. PSI data is collected annually for all divided and undivided state highways with exception of those located inside corporate limits of municipalities. More detail concerning the concept of Serviceability is presented in Section Project Level Pavement Management and Analysis Determination of the most cost effective time and treatment for the rehabilitation of a pavement is the most difficult problem a pavement engineer encounters. The solution to this problem is further complicated by funding uncertainties and shortages, as well as difficulties with plan preparation or detail design work which can create a delay of project delivery. The most cost effective treatment is dependent on pavement condition and the most cost effective time to treat a pavement depends upon the type of treatment involved. For example, a major rehabilitation should be delayed as long as possible in order to get the remaining life out of the existing pavement, as this type of treatment relies little on the existing structure. However, a preventive maintenance application must be done when the pavement is in good structural condition. In order to address any pavement section with some type of maintenance or rehabilitation treatment it is necessary to be able to predict pavement deterioration over time. Without knowing the condition of the pavement at the time of construction, it is impossible to prepare construction plans and fiscal budgets that will reflect the needs of the pavement PCR Historical Trends The most basic way of predicting pavement condition is by using the past to predict the future. The use of regression analysis is well suited for this purpose, however, it must be understood that past performance does not necessarily indicate the future. This type of analysis is easily performed by using PCR data as far back as the last action performed on a particular pavement section, and incorporating this data into a simple spreadsheet and performing a regression analysis PCR Performance Equations With the aid of research contracts, ODOT has developed models concerning pavement deterioration. The equations presented are a function of pavement type and the last activity performed on the pavement. For more information on the activities described, refer to Sections 500 and 600. These models should not be used without intuitive reasoning, as they were developed with data from the entire state network and may not be representative of every pavement section. Figure lists all available pavement performance models. January

15 Pavement Management Pavement Modeling The ability to predict the condition of a pavement is not a perfected technique at this time. However, using the equations in Figure as well as doing a regression analysis on the PCR data from the actual pavement and plotting this information does provide the pavement designer with some insight into performance trends. Figure is an example of such a plot. Figure displays a fictitious project which was rubblized and rolled in Provided in this figure is the actual PCR data, a regression of the actual PCR data, along with the appropriate pavement deterioration model for the fractured slab technique. All of this information is then graphed versus the year the data points apply. This example illustrates the use of this graphical representation as a tool which can be used to predict the condition of the pavement in the future. It can be seen that the predicted PCR of the fictitious pavement will likely be in the upper-50's in the year 2002 and may be a candidate for major rehabilitation if something is not planned for the year 2002 or earlier. January

16 100 Pavement Management List of Figures Figure Date Subject January 1999 Pavement Deterioration Models January 1999 Regression Analysis Spreadsheet

17 Pavement Deterioration Models January 1999 Reference Section 101 RIGID PAVEMENT Minor Rehabilitation: All Overlays with and without Repairs CPR New Rigid Pavement & Unbonded Concrete Overlay PCR = (AGE) PCR = (AGE) PCR = (AGE) FLEXIBLE PAVEMENT Minor Rehabilitation Non-Structural Overlay with Minimal Repairs Non-Structural Overlay with Repairs Structural Overlay with Minimal Repairs Generic Minor Rehabilitation (all of the above) Major Rehabilitation Fractured Slab Technique New Flexible Pavement PCR = (AGE) PCR = (AGE) PCR = (AGE) PCR = (AGE) PCR = (AGE) PCR = (AGE) COMPOSITE PAVEMENT Minor Rehabilitation Non-Structural Overlay with Minimal Repairs Non-Structural Overlay with Repairs Structural Overlay with Minimal Repairs Structural Overlay with Repairs Generic Minor Rehabilitation (all of the above) New Composite Pavement PCR = (AGE) PCR = (AGE) PCR = (AGE) PCR = (AGE) PCR = (AGE) PCR = (AGE)

18 Regression Analysis Spreadsheet January 1999 Reference Section 101 Year PCR Regression Model Regression Output Constant Std Err of Est R Squared No. of Observations Degrees of Freedom X Coefficient(s) Std Err of Coef Pavement Modeling Plot PCR Year PCR Regression Model

19 Table of Contents 200 Pavement Design Concepts Introduction Serviceability Initial Serviceability Terminal Serviceability Design Serviceability Loss Traffic Considerations Traffic Loading Conversion Factors Traffic Data B:C Ratios Design Lane Factors Calculation of ESAL s ESAL Subgrade Soil Characterization Subgrade Resilient Modulus California Bearing Ratio Group Index Soil Profile Analysis Unsuitable Subgrade Soil Soil Stabilization Methods Reliability Overall Standard Deviation Subsurface Pavement Drainage Types of Drainage Systems Pipe Underdrains Prefabricated Edge Drains Aggregate Drains Free Draining Base Options AASHTO Drainage Coefficient...2-6

20 200 Pavement Design Concepts Introduction Perhaps the most widely used pavement design method used in the United States and throughout the world is that presented in the AASHTO Guide for Design of Pavement Structures. A long history of pavement studies has lead to the current (1993) edition. The ODOT method for the design of pavement structures is almost identical to the AASHTO method, but ODOT has simplified some parts of the AASHTO Guide since it needs to apply only to the conditions encountered in Ohio. The AASHTO / ODOT pavement design equations have some variables that are common to both rigid and flexible pavement, including: serviceability, traffic loading, reliability, overall standard deviation, and roadbed soil resilient modulus. The remaining variables needed for the design of a pavement structure are presented in the respective rigid and flexible pavement sections on design procedures. 201 Serviceability ODOT s Pavement Design Method (AASHTO) is developed around the concept of serviceability, which serves as the pavement performance parameter by which a pavement s condition is valued. Serviceability is defined as the ability of a pavement to serve traffic. The Present Serviceability Rating (PSR) was developed to measure serviceability. PSR is a rating of pavement ride based on a scale of 0, for impassible, to 5, for perfect. For the development of the original AASHTO Pavement Design Equation, individuals (the raters) would ride the pavements and assign a PSR value. To avoid riding and rating every pavement by all raters to determine serviceability, a relationship between PSR and measurable pavement attributes has been developed. This relationship is defined as the Present Serviceability Index (PSI) Initial Serviceability Data obtained by the Office of Technical Services (see Section 100.3) indicates that pavements constructed in Ohio in the past have averaged an initial PSI of 4.2 for rigid pavements and 4.5 for flexible pavements Design Serviceability Loss The design serviceability loss is the amount of serviceability the agency will tolerate losing before rehabilitation. The design serviceability loss is defined as the difference between the terminal serviceability and the initial serviceability. Figure lists the design serviceability loss. 202 Traffic Considerations Perhaps the most important step in designing a pavement is the estimation of the design traffic. Overestimation of the design traffic results in a thicker pavement than necessary with higher associated costs. Underestimation of traffic results in a thin pavement that will fail prematurely causing increased maintenance and impact on the user Traffic Loading For design purposes, all traffic is converted to a traffic load which is normalized by the concept of an Equivalent 18,000 lb (80 kn) Single Axle Load (ESAL). The conversion of traffic to the ESAL is accomplished with the use of axle load equivalency factors. Equivalency factors are a function of pavement type and thickness, among other factors. Equivalency factors are provided in the AASHTO Guide Conversion Factors In order to simplify the process of converting each truck expected on the roadway to an ESAL, ODOT uses ESAL conversion factors for the average of groups of trucks. The vehicles are grouped into two categories: single or C units, and tractor-trailer or B combinations. As truck numbers and axle weights are being monitored continuously, conversion factors are calculated yearly by the Office of Technical services for both truck types for the different functional classifications being monitored. The conversion factors printed in this manual are based on a rolling ten-year average of the data provided by the Office of Technical Services and are updated as necessary when significant changes in the ten-year rolling average are found. Refer to Figure for ODOT s most current ESAL Conversion Factors Terminal Serviceability ODOT pavements are designed for a minimum PSI (terminal serviceability) of 2.5. January

21 Pavement Design Concepts Traffic Data Basic traffic data should be forecasted and certified by the Office of Technical Services or the District. This data must include the Average Daily Traffic (ADT) and the 24-hour truck percentage for the current year as well as the design year, twelve or twenty years hence. This data is typically found in the Design Designation for the project. It is important to insure the truck percentage is a 24- hour percentage and not a peak hour percentage B:C Ratios Truck counts can be broken down into two truck type categories. The larger trucks such as 4 or more axle single units and semi-tractor trailers are classified as B type trucks. Smaller trucks such as three axle single units and buses are classified as C type trucks. The Office of Technical Services collects this data on a sampling basis and reports the data using statewide averages by functional classification. B:C Ratios are presented in Figure These ratios should be used only where current project counts are not available. Actual B & C counts are always more accurate than the B:C ratio provided in Figure Design Lane Factors Average Daily Traffic (ADT) counts always include all lanes and both directions of travel. In order to design the required pavement thickness, the ADT needs to be adjusted to represent the loading on the design lane. This is done by applying the Directional Distribution, which defines the loading in each direction of travel, and the Lane Factor, which distributes the trucks into the different lanes. The Design Designation generally indicates a directional distribution other than 50%, however this distribution represents the peak-hour volume and is used for geometric design purposes. Unless the designer has specific, credible information indicating unequal loading on the two directions, and this imbalance is expected to continue throughout the design life of the pavement, it should be assumed that each direction will have equal loading over the design life and a directional distribution of 50% used. If the designer is certain loading is unequal, a directional distribution other than 50% may be used but caution is advised as this can have significant impact on the on the pavement thickness required. Refer to Figure for ODOT s most current Lane Factors Calculation of ESAL s The calculation of ESAL s is very simple once all the data is available. The following equations are used. All percentages are to be expressed as a decimal. ADT * %T24 * D * LF * %B * CF = B ESAL s ADT * %T24 * D * LF * %C * CF = C ESAL s B ESAL s + C ESAL s = Total ESAL s Where: ADT = Average Daily Traffic %T24 = 24-hour truck percentage of ADT D = Directional Distribution LF = Lane factor %B, C = % B or C trucks of the total trucks CF = Appropriate truck conversion factor Examples of the calculation of design ESAL s are provided in Figures and ESAL99 Another method for the calculation of ESAL s is available for locations where historical traffic data is available. This method takes into account growth rates in numbers of trucks as well growth rates in the conversion factors associated with the trucks. The method relies on the practice of forecasting the future based on trends of the past. However, trends of the past may not be an indication of future performance. For more information regarding this method contact the Office of Materials Management, Pavements Section. 203 Subgrade Soil Characterization The subgrade is the foundation for all pavements. Trying to characterize the strength of this foundation for a particular pavement is a very difficult task because of the variability found in nature and during construction. The AASHTO pavement design equations used by ODOT require the characterization of the strength of the subgrade by using the roadbed soil resilient modulus. For design of pavement, subgrade soil type is determined directly from soil tests made in conjunction with the soil profile or bridge foundation investigations. In Ohio, soils are classified based January

22 Pavement Design Concepts on gradation and Atterburg Limits. Figure represents the classification system for Ohio soils. On all new location projects it is imperative that a complete soils investigation and soil profile (subsurface investigation) be performed prior to pavement design. Pavement design for pavement replacement projects and pavement widening projects can be performed using a historical subsurface investigation, where it exists, however, it is recommended to perform an additional subsurface investigation to design for weak subgrade conditions and to validate the pavement design calculations. The need for soils information regarding major rehabilitation projects is covered in Section In order to insure sufficient information will be obtained from a soils investigation, refer to ODOT s Specifications for Subsurface Investigations. General information about soil types can be found in the Soil Survey books which are published for every county in Ohio. Additional information on soils and proper construction practices can be found in the Manual of Procedures for Earthwork Construction put out by the Office of Highway Management Subgrade Resilient Modulus The subgrade resilient modulus is a measure of the ability of a soil to resist permanent deformation under repeated loading. Many soils are stress dependent. As the stress level increases, these soils will behave in a nonlinear fashion. Finegrained soils tend to be stress-softening, whereas granular soils tend to be stress-hardening. The laboratory test (LTPP P 46) is designed to determine the strain due to a repeated load (deviator stress) which duplicates the effects of loads passing over a section of pavement. Based on limited research and several current publications, ODOT has adopted a standard relationship between Modulus of Resilience and the California Bearing Ratio (CBR). Equation 203.1: M r = 1200 * CBR California Bearing Ratio The California Bearing Ratio (CBR) is most commonly obtained by doing a laboratory penetration test of a soaked sample of soil. The load required to produce a penetration at each 0.1 inch depth in the soaked sample is divided by a standard which has been developed for crushed stone. CBR CRUSHED STONE STANDARD PENETRATION LOAD 0.1 INCH 1000 PSI 0.2 INCH 1500 PSI 0.3 INCH 1900 PSI 0.4 INCH 2300 PSI 0.5 INCH 2600 PSI Group Index The Group Index (GI) is a value which represents a soil type and attempts to characterize the soils strength. GI is a function of a soil s Atterberg Limits and gradation. Group Index is defined by the following equation: Equation 203.3: GI = %P - 35* [ * (L.L. - 40)] * [%P - 15]*[P.I. - 10] Where: %P = The percentage passing the #200 sieve. L.L. = The Liquid Limit which is the water content at which a soil flows like a viscous liquid. P.I. = The Plasticity Index which is the numerical difference of the liquid and plastic limits, and indicates the range of water content through which the soil flows. The nomographs shown in Figure solve Equation In order to reduce the amount of laboratory testing required to characterize the soil strength, ODOT developed a relationship between CBR and Group Index. This relationship was developed in the early 1960's by testing thousands of soil samples. Figure provides a correlation chart to convert the Group Index to the CBR. January

23 Pavement Design Concepts Soil Profile Analysis The soil profile is one of the most useful tools for any geotechnical analysis. This manual only considers the usefulness of the soil profile as it applies to pavement design. Using the soil profile, the Atterberg Limits and GI can be obtained directly for most samples. Where complete soil classifications are not provided, refer to Figure for estimates of GI. The most appropriate GI to use for pavement design is determined by using engineering judgment. Consideration should be given only to the soil located within the top 3 feet (1m) of proposed subgrade. An average soil type is to be used for pavement design. ODOT s Pavement Design Procedure uses a statistical reliability factor (see Section 204) to account for the variability found in the subgrade strength. The most common error found when reviewing pavement designs is the use of a CBR value which is too conservative, in other words using the worst soil rather than the average. Determination of the soil type and strength parameters for borrow used in fill situations should be considered. An assumption must be made as to where the borrow will come from. Usually it is assumed that the borrow will come from somewhere nearby and will likely be the same soil type. Evaluation should also include consideration of the cut material to be used for fill Unsuitable Subgrade Soil Frost susceptible silts are never to be used within one meter of proposed subgrade elevation. These soils are classified as A-4b and should be set up for undercut and replacement with suitable subgrade materials. It is important to remember that these soils will not be part of the subgrade and should not be included in the average soil strength value used for design. Weak-wet soils with blow counts of only one or two are not suitable for subgrade under pavement, and should be removed and replaced with suitable material, or stabilized with lime or cement Soil Stabilization Methods ODOT CMS Item 206 Lime Soil Stabilized Subgrade is available for use on subgrade which has high clay content. Although it is commonly assumed that the stabilization of the soil results in higher subgrade strength, ODOT s current design methods do not provide for reduced pavement section as a result of modified subgrade. ODOT CMS provides requirements for Type D Geotextile Fabric. This fabric can be used at the bottom of undercuts as a separator between unsuitable clay or silt and the proposed granular embankment or aggregate base. The separator keeps the migration of clay and silt from closing the voids in the layers above and causing settlement and/or pumping. Geotextile fabrics are often recommended to be used as a construction aid to speed construction, but should not be used to thin the required pavement thickness. Geotechnical recommendations regarding proper embankment construction, including subgrade treatment, may be requested from the Office of Materials Management, Geotechnical Design Section. 204 Reliability AASHTO defines Reliability as the probability that the load applications a pavement can withstand in reaching a specified minimum serviceability level is not exceeded by the number of load applications that are actually applied to the pavement. Technically, reliability is a statistical tool used in pavement design which assumes a standard normal distribution exists for all pavement design parameters and allows the designer to account for deviation from the average, equally for all parameters. Reliability parameters can be thought of as safety factors. Figure lists the Reliability Factors to be used in pavement design for various classifications of highways. January

24 Pavement Design Concepts Overall Standard Deviation The overall standard deviation (variance) is a measure of the spread of the probability distribution for ESAL s vs. Serviceability, considering all the parameters used to design a pavement. Figure lists the Overall Standard Deviation to be used in pavement design. 205 Subsurface Pavement Drainage Subsurface pavement drainage is required on all projects. Lack of adequate pavement drainage is the primary cause of distress in many pavements. Excess moisture in the base and subgrade reduces the amount of stress the subgrade can tolerate without strain. Strain in the subgrade transfers the stress into the upper pavement layers which induces deformation, and ultimately distress. Trapped moisture in flexible pavement systems leads to stripping, raveling, debonding, and rutting. Excess moisture in rigid pavement systems leads to pumping, faulting, cracking, and joint failure. Several approaches are available to keep pavement systems drained. Joint and crack sealing can be done to reduce the infiltration of water. Strategic placement of underdrains and edgedrains is used to capture the water quickly and outlet it. The use of free draining base is promoted to capture all pavement drainage Types of Drainage Systems There are four means of draining the pavement subsurface - pipe underdrains, prefabricated edge drains, aggregate drains and free draining base systems Pipe Underdrains Pipe underdrains must be used for all Interstate, freeways, expressways, and multi-lane facilities. Pipe underdrains are generally used with paved shoulders and curbed pavements. Refer to Figures to of the Location & Design Manual, Volume 2 - Drainage Design; and Location & Design Manual, Volume 3 - Highway Plans, Sample Plan Sheets for locations of pipe underdrains with the various pavement - shoulder treatments. Special consideration must be given to the design of pipe underdrains for free draining base options. Refer to Section Prefabricated Edge Drains Prefabricated edge drains are located at the edge of existing concrete pavement on resurfacing projects where the existing pavement and paved shoulders are being retained. If existing paved shoulders are being replaced, a 4 inch (~100 mm) shallow pipe underdrain at the edge of pavement should be used in lieu of the prefabricated edge drain. On resurfacing projects, where edge drains already exist, existing outlets should be inspected and replaced where they no longer function Aggregate Drains Aggregate drains are used with bituminous surface treated shoulders, aggregate shoulders, and for spot improvements. Aggregate drains are used on lower volume roadways with bituminous stabilized or turf shoulders, or any pavement system which does not have pipe underdrains or prefabricated edgedrains. Drains should be located at 50-foot (~15 m) intervals on each side of the pavement and staggered so each drain is 25 feet (~7.5 m) from the adjacent drain on the opposite side. If used on rigid pavements, the drains should be located to match up to the end of a transverse joint. For superelevated pavements, spacing should be at 25 feet (~7.5 m) and drains should be located on the low side only. Aggregate drains should be physically cut into the edge of the pavement - shoulder system, preferably the aggregate base. Refer to Figures and of the Location & Design Manual, Volume 2 - Drainage Design; and Location & Design Manual, Volume 3 - Highway Plans, Sample Plan Sheets for details depicting aggregate drains with the various pavement - shoulder treatments Free Draining Base Options It is generally accepted that water is one of the most significant causes of pavement deterioration. A free draining base (FDB) placed within a pavement system is highly effective at removing water which enters the pavement system from the surface after a rain shower or other precipitation. Free draining base systems should be considered for all multi-lane facilities. Free draining bases may not be feasible in urban settings where utilities are numerous because the ability to properly construct and maintain a free draining base is greatly reduced where manholes, catch basins, water lines, and other utilities are present. Where a free draining base is specified it should not extend into the ramps or crossroads. January

25 Pavement Design Concepts There are two basic types of free draining bases for use under pavements: stabilized and nonstabilized. Stabilized free draining base consists of a blend of #57 and #8 aggregate with a Portland cement or asphalt cement binding agent. Cement Treated Free Draining Base is Item 306 and Asphalt Treated Free Draining Base is Item855. The stabilized bases provide a very stable construction platform and allow the contractor to use the base as a haul road for short periods of time. The contractor must accept all risk for the potential damage to the base. Non-stabilized free draining bases, Item 307, have three different gradations, none of which are stable enough to be used for a haul road but which have ample stability for paving. All but one of the free draining bases are 4 inches (~100 mm) thick, the exception being the non-stabilized Type CE, which is 6 inches (~150 mm) thick. The choice of free draining base type is dependent upon pavement type, constructability and preference. There are concerns regarding the use of a stabilized free draining bases because of the relatively short time they have been used and the lack of performance data which is available. In fact, there are not yet any available studies which have been done nationwide which indicate the cost effectiveness of using any FDB. Ohio has documented the non-stabilized free draining base- Type NJ may be inducing premature midpanel cracking under rigid pavements and its use under rigid pavements is not recommended. There are separate concerns regarding the use of a stabilized free draining base, due to the potential for long term erosion of the binding agent. All free draining base courses must include a 6 inch (~150 mm) layer of Item 304 Aggregate Base placed below the free draining base. This layer contributes to the structural capacity of the pavement, provides a stable platform for paving and acts as a filter to prevent the migration of the subgrade into the free draining base, potentially closing the voids and clogging the drains. Item 408 Prime Coat is required on the surface of the aggregate base to prevent the fines contained in the aggregate base from washing into the drainage system. The prime coat should be applied at 0.4 gallons per square yard (~1.8 liters per square meter) on top of the aggregate base, everywhere except above the underdrain trenches. Two separate drainage systems are used with pavements which have a free draining base. One set of underdrains is provided exclusively for the free draining base, and a second set is provided exclusively for the subgrade. Since the FDB layer collects and drains water between the load carrying layers, sound and committed maintenance is essential in order to provide the performance benefits of this base course. Free draining bases should not be constructed if they are not going to be maintained throughout the life of the pavement. Maintenance consists mainly of making sure the outlets are functioning properly and are not clogged with debris or blocked in some way. Consideration should be given to marking outlets with sign and post for projects with free draining base. For examples of typical sections depicting FDB refer to Figures and of the Location & Design Manual, Volume 2 - Drainage Design AASHTO Drainage Coefficient The AASHTO pavement design equations attempt to consider the effects of drainage on pavement performance. The nomographs used in this manual are reprinted from AASHTO and allow for the use of the drainage coefficient for rigid pavement design. The flexible design method in this manual does not include the drainage factor. For ODOT pavement design the Drainage Coefficient shall always be 1.0 for design of both rigid and flexible pavements. January

26 200 Pavement Design Concepts List of Figures Figure Date Subject January 1999 Serviceability & Reliability January 1999 Traffic Factors January 1999 Legend and Classification of Soils January 1999 Group Index Charts January 1999 Subgrade Resilient Modulus

27 Serviceability & Reliability January 1999 Reference Section 201 & 204 SERVICEABILITY FACTORS RIGID / COMPOSITE FLEXIBLE Initial Serviceability Terminal Serviceability Design Serviceability Loss RELIABILITY LEVELS (%) FUNCTIONAL CLASSIFICATION URBAN RURAL Interstate and Freeway Principle Arterial, Minor Arterial Collectors Local OVERALL STANDARD DEVIATION Flexible Pavement 0.49 Rigid Pavement 0.39

28 Traffic Factors January 1999 Reference Section 202 RATIO OF B:C COMMERCIAL VEHICLES FUNCTIONAL CLASSIFICATION B:C RATIO Rural Interstate 5:1 Rural Principal Arterial 4:1 All Other Rural 2:1 Urban Interstate, Urban Freeway & Expressway, & Urban Principal Arterial 2:1 All Other Urban 1:2 ESAL CONVERSION FACTORS FUNCTIONAL CLASSIFICATION RIGID FLEXIBLE B C B C Rural Interstate Rural Principal Arterial Rural Minor Arterial (All Others) Urban Interstate Urban Expressway & Freeway Urban Principal Arterial (All Others) LANE FACTORS Number of Lanes % Trucks in Design Lane Directional Distribution (%) 2 - Lane Lane (or more) - Lane 80 50

29 Ohio Soils Classification System January 1999 Reference Section 203

30 Group Index Charts January 1999 Reference Section 203

31 Subgrade Resilient Modulus January 1999 Reference Section 203

32 Table of Contents 300 Rigid Pavement Design Procedures & Considerations Introduction Design Parameters Modulus of Rupture Modulus of Elasticity Load Transfer Coefficient Composite Modulus of Subgrade Reaction Loss of Support Effective Modulus of Subgrade Reaction Thickness Determination Ramps and Interchanges Jointing and Shoulder Considerations Transverse Joints Expansion Joints Longitudinal Joints Shoulder Considerations Edge Course Design Intersection Jointing Details Smoothness Specifications Composite Pavement Composite Pavement Design Composite Pavement Typical Section Design Composite Pavement Smoothness Specifications...3-4

33 300 Rigid Pavement Design Procedures & Considerations Introduction Rigid pavements can be constructed with contraction joints, expansion joints, doweled joints, no joints, temperature steel, continuous reinforcing steel, or no steel. Regardless of the type of rigid pavement to be constructed, the ODOT/AASHTO method of pavement design calculates the same required thickness. The required thickness is a function of loading, material properties including subgrade, and the type of joints, if any. Alterations to rigid pavement material specifications, jointing considerations, and mesh provisions other than those provided in ODOT s Construction and Material Specifications or ODOT s Standard Construction Drawings may require adjustments to the procedures described herein. Additional information on rigid pavement and proper construction practices can be found in the Manual of Procedures for Rigid Pavement Practices and the Manual of Procedures for Concrete put out by the Office of Highway Management 301 Design Parameters ODOT s method for the design of rigid pavement limits the designer to prescribed input parameters. The input values prescribed are based on Ohio materials, and ODOT Specifications Modulus of Rupture Modulus of Rupture, as determined under a breaking load, measures the flexural strength or extreme fiber stress, of the concrete slab. There are many ways to determine the modulus of rupture and each way will give slightly different results; however, each method can be correlated to the measure defined for use in the AASHTO/ODOT method. The modulus of rupture as defined for ODOT s pavement design method is the 28 day - third point loading test as defined by ASTM C 78. All rigid pavement design should use a Modulus of Rupture of 700 psi, as shown in Figure Average values obtained through beam breaks performed as part of ODOT Construction and Material Specification requirements should not be used directly for design purposes, as this test is defined by ASTM C 293 as a center point loading, and are generally done as early as 5 days Modulus of Elasticity The modulus of elasticity of concrete is a function of the strength, age, aggregate properties, cement properties, and type and size of the specimen tested as well as rate of loading during the test. Furthermore there are various methods used to determine the modulus of elasticity. ODOT s method for rigid pavement thickness design is not highly sensitive to the value used for modulus of elasticity. Based on values obtained by recent ODOT research, a Modulus of Elasticity of 5,000,000 psi should be used for all rigid pavement design. The Modulus of Elasticity is also listed in Figure Load Transfer Coefficient The load transfer coefficient (J) is a factor used in rigid pavement design to account for the ability of a concrete pavement to transfer (distribute) load across discontinuities, such as joints or cracks. Load transfer devices, aggregate interlock, widened lanes, and the presence of tied concrete shoulders all have an influence on this value. J factors are listed in Figure Composite Modulus of Subgrade Reaction The Composite Modulus of Subgrade Reaction represents the combined effect of the subgrade strength or subgrade modulus of resilience, as discussed in Section 203.1, and the strength, or elastic modulus, and thickness of the subbase material. The pavement design process requires the designer to choose the subbase prior to the determination of the required slab thickness. The values to be used for the elastic modulus of the subbase for ODOT materials is listed in Figure Figure is a nomograph which determines the Composite Modulus of Subgrade Reaction. For uncurbed pavements carrying more than 50 ESAL s per day and for curbed pavements carrying more than 100 ESAL s per day, a 6 inch granular base (Item 304) is recommended to prevent pumping for concrete pavements on fine grained soils. January

34 Rigid Pavement Design Procedures & Considerations Loss of Support Loss of Support, (LS), is included in the design of rigid pavements to account for the potential loss of support arising from subbase erosion and/or differential vertical soil movements. The potential of a material to pump is a good indicator of LS. It is treated in the actual design procedure by diminishing the composite modulus of subgrade reaction. Figure list the LS factors to be used for ODOT materials Effective Modulus of Subgrade Reaction The Effective Modulus of Subgrade Reaction is the Composite Modulus of Subgrade Reaction as modified by the Loss of Support. Figure is a nomograph which determines the Effective Modulus of Subgrade Reaction. 302 Thickness Determination Assembly of all the design input information is required prior to determination of design thickness. Design thickness is determined using the nomographs found in Figures and An example rigid pavement design is provided in Figure Concrete pavements should be rounded to the nearest 0.5 inch (~10 mm) increment Ramps and Interchanges Ramps and Interchanges also require traffic and soils information for thickness design. However, some discretion must be used regarding the calculation of ESAL s. In general, use the lower functional classification factors of the two intersecting routes for Reliability, B:C Ratio, and ESAL Conversion Factors. 303 Jointing and Shoulder Considerations Transverse Joints Transverse joints are provided to control cracking. The closer the joint spacing, the less likely a midpanel crack will develop. Ohio uses 17-foot (~5 m) joint spacing for plain concrete. For reinforced concrete 60 feet was used before about 1967 when it was reduced to 40 feet. Then in the early 1980's it was further reduced to 27 feet for several more years and then to the current standard of 21 feet (~6.5 m). Current analysis indicates the plain concrete pavement has a lower initial cost than the reinforced concrete pavement. However, uncertainties exist regarding the development of midpanel cracking in plain concrete pavement. Current preference is to construct Item 452 Plain Concrete Pavement above dense graded bases (Item 304) and Item 451 Reinforced Concrete Pavement above Free Draining Bases (Items 306, 307 Type IA, and 855). Load transfer is the critical element at joints and cracks. In undoweled, unreinforced pavements, load transfer is provided by aggregate interlock. Aggregate interlock is lost when slabs contract and the joints/cracks open up. Interlock is also slowly destroyed by the movement of the concrete as traffic passes over. Given the high temperature variations and heavy truck traffic in Ohio, aggregate interlock is not effective and faulting is the primary result. To provide load transfer at the joints, 18 inch (~460 mm) smooth dowels are used which allow for expansion and contraction. Transverse joint design and spacing requirements are shown in the Standard Construction Drawings Expansion Joints As slabs contract due to seasonal temperature changes, joints open and cracks form allowing incompressible materials into the pavement system. Subsequently, the pavement can grow in length and the possibility of pushing a bridge backwall, or creating a pavement pressure spall, or a pavement blowup exists Having a certain amount of pressure in a pavement is good, since lack of pressure allows joints and cracks to open which reduces load transfer. Pressure buildup in rigid pavements seldom creates pavement distress. Nonetheless, when distresses are found, they tend to require some type of maintenance, and may require immediate care in the case of a blowup. The most immediate need for an expansion joint or a pressure relief joint is to protect bridge backwalls. Four types of pressure relief joints are detailed in the Standard Construction Drawings. For new pavement construction, the Type A joint should be provided at all bridge approaches where the bridges are over 300 feet (~90 m) apart. Where bridges are less than 300 feet (~90 m) apart, the standard expansion joints as required by Item 451, 452 and 305 of the Construction and Material Specifications and detailed in the Standard Construction Drawings are considered adequate. Use of pressure relief joints for January

35 Rigid Pavement Design Procedures & Considerations pavements being rehabilitated is discussed in Section Longitudinal Joints Longitudinal joints are required whenever the pavement width exceeds 18 feet (~5.4 m). Ideally, the joints should be located at lane lines, and out of the wheel paths. Unless advised otherwise, best practice dictates to tie all lanes together using a Standard Longitudinal Joint as detailed in the Standard Construction Drawings. At intersections, where two independent pavements meet, a longitudinal joint without tie bars is required to separate the two pavements and allow for independent movement Shoulder Considerations Shoulders are used to provide an area for the accommodation of disabled vehicles, for the lateral support of the base and surface courses, to improve the safety of a highway, and for future maintenance of traffic operations during maintenance and rehabilitation work. Shoulders for concrete pavements shall be constructed of the same material and thickness as the mainline pavement for all Interstate, freeways, expressways, and other multi-lane divided facilities. This provides a stable temporary pavement for maintenance of traffic lane shifts, and reduces the complexity of construction. Tying concrete shoulders onto the mainline provides lateral support and spreads the load over a greater area. Using other types of shoulders, such as flexible, bituminous surface treated, stabilized aggregate, or turf shoulders should be in accordance with Geometric Standards, discussed in the Location & Design Manual, Volume One - Roadway Design. Regardless of shoulder type, shoulder base and subgrade considerations should include keeping drainage away from the pavement, rather than towards it. Examples of typical sections depicting rigid pavement with different types of shoulders are shown in Figure Edge Course Design The Aggregate Base for a rigid pavement shall extend 18 inches (~450 mm) beyond the pavement edge, or to the outside edge of the porous backfill over the pipe underdrain, or to 6 inches (~150 mm) beyond the outside edge of the paved shoulder, whichever is greater. Where curb and gutter or integral curb is used, subbase shall extend 12 inches (~300 mm) beyond the back of the curb or to the outside of the porous backfill over the pipe underdrain, whichever is greater. Refer to Hydraulics Manual and Sample Plan Sheets Intersection Jointing Details Intersections require careful consideration of the joint layout and dowel and tie bar placement. In order to ensure load transfer and that cracking is controlled properly and both intersecting pavements do not hinder the movement of one another, jointing diagrams should be provided as part of the plans. Joint diagrams should be designed with consideration to maintenance of traffic needs as well as ease of construction. The number of longitudinal joints should be kept to a minimum, and all lanes should be the same width. Examples of jointing diagrams are included in the Location & Design Plan Preparation Sample Plan Sheets-Volume Three. Also, there are various publications provided by the American Concrete Pavement Association (ACPA) which provides guidance for intersection jointing layout. 304 Smoothness Specifications Incentive/disincentive for smoothness is specified using Proposal Note , 452 and 453 Surface Smoothness Requirements. The Note is to be used on all projects which have in excess of 1 center-line mile (~1.6 center-line km) of concrete pavement. However, ODOT CMS smoothness requirements are more appropriate for urbanized routes with speed limits posted under 50 miles per hour, regardless of size of project. 305 Composite Pavement Composite pavement herein refers to a rigid base with an asphalt surface. Generally the design of a composite pavement is discouraged due to the relative performance and associated costs. Where local preference is strong and there has been good performance of composite pavements, consideration may be given to the design and specification of a composite pavement. January

36 Rigid Pavement Design Procedures & Considerations Composite Pavement Design Composite pavements are designed as rigid pavements. Once the required thickness is determined, common practice is to reduce the concrete thickness by one inch (~25 mm) and replace it with 3 to 3.25 inches (~75 mm - 83 mm) of asphalt overlay. This ratio of 1 inch of concrete to 3 inches of asphalt only holds true for the first inch of concrete removed, and is a approximation at best. The minimum overlay thickness on a rigid pavement or base is 3 inches (~76 mm). The reduction in required thickness should be done prior to rounding to the nearest 0.5 inch (~10 mm) Composite Pavement Typical Section Design. Composite pavement should be constructed using Item 305 Concrete Base. The concrete base shall extend beyond the wearing surface by 3 inches (~75 mm). Item 413 Sawing and Sealing Asphalt Concrete Pavement Joints shall be used for all newly constructed composite pavements Composite Pavement Smoothness Specifications Incentive/disincentive for smoothness on composite pavement applies to the asphalt surface only. The guidelines in Section 405 apply. January

37 300 Rigid Pavement Design Procedures & Considerations List of Figures Figure Date Subject January 1999 Rigid Pavement Design Parameters January 1999 Composite Modulus of Subgrade Reaction (Kc) January 1999 Effective Modulus of Subgrade Reaction (K) January 1999 Rigid Pavement Design Example, Page June 1999 Rigid Pavement Design Example, Pages 2 and January 1999 Rigid Pavement Design Chart Segment January 1999 Rigid Pavement Design Chart Segment January 1999 Bituminous Surface Treated Shoulder And Stabilized Aggregate Shoulder Typical Sections

38 Rigid Pavement Design Parameters January 1999 Reference Section 301 MATERIAL PROPERTIES Modulus of Rupture (S C ) Modulus of Elasticity (E C ) 700 psi 5,000,000 psi Load Transfer Coefficient (J) - Doweled, Edge Support* 2.8 Load Transfer Coefficient (J) - Doweled, No Edge Support* 3.2 SUBBASE FACTORS ODOT Specification Recommended Thickness (in.) (DSB) Elastic Modulus (PSI) (ESB) Loss of Support (LS) Item 301, 302 Bituminous Aggregate Base 4" 300,000 0 Stabilized (Treated) Free Draining Base with Item 304** Non-Stabilized Free Draining Base with Item 304** 10" 6" 304 / 4" SFDB 10" 6" 304 / 4" NSFDB 30, ,000 0 Item 304 Aggregate Base 6" 30,000 1 Natural Subgrade *** 2 * Edge support includes tied concrete shoulders, integral curb, widened lane, etc. Widened lane refers to concrete slabs built 14 feet (~4.2 m) wide or wider, but striped for a standard 12-foot (~3.6 m) lane, leaving 2 feet (~0.6 m) outside the traveled lane to provide edge support. ** The use of a free draining base always includes a 6-inch (~150 mm) layer of Item 304 Aggregate Base to be used as a filter layer and is used to keep the subgrade from infiltrating and plugging the free draining base. The values to be used in the table represent the combined effect of the strength of the 6-inch (~150 mm) aggregate base filter layer, as well as the free draining base layer. *** Not recommended for most applications. See Section 301.4

39 Composite Modulus of Subgrade Reaction (Kc) January 1999 Ref. Section & Figure 301.4, (step 4)

40 Effective Modulus of Subgrade Reaction (k) January 1999 Ref. Section & Figure 301.6, (step 5)

41 Rigid Pavement Design Example Page January 1999 Reference Section 302 Example - Rigid Pavement Design Givens: Pavement of choice: Doweled, jointed concrete Subbase: 6 inches Item 304 Aggregate Base Shoulders: Tied, jointed, concrete Number of Lanes: 4 Functional Classification: Rural Principal Arterial 1998 Traffic: 14,800 ADT 2018 Traffic: 23,360 ADT 24 hour truck % 10 Year Completed: 2000 Soil Classification: Liquid Limit = 45 Plasticity Index = 12 % Passing #200 sieve = 70 Problem: Solve for the thickness of the concrete slab. Solution: Step 1 - Determine the Group Index Number (G.I.) Using Figure In chart A, solve for the Partial Group Index using the 70 % Passing No. 200 Sieve and the Liquid Limit (L.L.) Of 45. G.I. from Chart A = 7.9. In Chart B, solve for the Partial Group Index using the 70 % (55 or more) Passing No. 200 Sieve and the Plasticity Index of 12. G.I. from Chart B = 0.8. The total G.I. is 7.9 plus 0.8 or 8.7 (Rounded to 9). Step 2 - Determine the Subgrade Resilient Modulus (M R ) using Figure Using a G.I. of 9 from Figure (Step 1), the California Bearing Ratio (CBR) is 6 (Rounded). The CBR is used in the following formula to determine the Resilient Modulus. M R = 1200 X 6 = 7200 psi.

42 Rigid Pavement Design Example Page June 1999 Reference Section 302 Step 3 - Determine the 18-kip Equivalent Single Axle Loading (ESAL). Since the project is expected to begin carrying traffic in the year 2000, the traffic period would be 2000 to 2020, with a mid-year of 2010 and an interpolated ADT of 19,936. Directional Distribution, D = 50 % (Figure 202-1) Lane Factor =.90 (Figure 202-1) B:C Ratio = 4:1 (Figure 202-1) B factor = 2.36 (Figure 202-1) C factor = 1.02 (Figure 202-1) Using the equations given in Section 202.2: ESAL's from B trucks: 19,936(0.10)(0.50)(0.90)(4/5)(2.36) = 1,693.8 ESAL ESAL's from C trucks: 19,936(0.10)(0.50)(0.90)(1/5)(1.02) = ESAL Total ESAL's 1,876.8 ESAL s per day Design Period ESAL's = 1,876.8 X days/yr. X 20 year = 13,709,842 say 13.7x10 6 ESAL s Step 4 - Determine the Composite Modulus of Subgrade Reaction (K c ) using Figure Starting with the given subbase thickness (D SB ) of 6", a line is projected up to the Subbase Elastic Modulus (E SB ) curve of 30,000 psi (Item 304 Aggregate Base from Figure 301-1). From this point on the 30,000 psi curve, a line is projected to the right for future intersection. Similarly, from the 6" subbase thickness (D SB ), a line is projected down to the Subgrade Resilient Modulus (M R ) curve of 1200 psi ( Figure 203-3, Step 2). From this point on the 1200 psi curve, a line is projected to the right to the turning line and then projected up to intersect with previously projected line. This intersection results in a Composite Modulus of Subgrade Reaction (K C ) of 400 pci. Step 5 - Determine the Effective Modulus of Subgrade Reaction (K) using Figure The Composite Modulus of Subgrade Reaction (K c ) is 400 pci from Figure 301-2, Step 4. The Loss of Support (LS) for Item 304 Aggregate Base is 1.0 from Figure This results in a K of 130 pci.

43 Rigid Pavement Design Example Page June 1999 Reference Section 302 Step 6 - Determine the thickness of the concrete slab using Figures and Figure is used to solve for the Match Line Number using the following information: Effective Modulus of Subgrade (K) = 130 pci (Figure 301-3, Step 5). Concrete Elastic Modulus (E C ) = 5,000,000 psi (Figure 301-1). Concrete Modulus of Rupture (S C ) = 700 psi (Figure 301-1) Load Transfer Coefficient (J) (Figure 301-1). Drainage Coefficient (C D ) = 1.0 (Section 205.2). The resulting Match Line Number of 62 is then used on Figure 302-3, along with the following information, to solve for the Design Slab Thickness (D). Design Serviceability Loss (PSI) = 1.7 (Figure 201-1). Reliability = 85% (Figure 201-1). Overall Standard Deviation = 0.39 (Figure 201-1). 18-kip Equivalent Single Axle Load = 13.7x10 6 ESAL (Step 3) Therefore: Design Slab Thickness (D) = 9.6 inches Use 9.5 inches

44 Rigid Pavement Design Chart Segment January 1999 Ref. Section & Figure 302, (step 6)

45 Rigid Pavement Design Chart Segment January 1999 Ref. Section & Figure 302, (step 6)

46 Bituminous Surface Treated Shoulder and Stabilized Aggregate Shoulder Typical Sections January 1999 Reference Section 205.1, 303.4, 303.5

47 Table of Contents 400 Flexible Pavement Design Procedures & Considerations Introduction Design Parameters Structural Number Determination Ramps and Interchanges Typical Section and Buildup Considerations Typical Section Design Shoulder Buildups Edge Course Design Paved Shoulder Edge Course Design Lift Thickness and Specification Guidelines All Item 446 & 448 Type 1 and Type 2 Courses Superpave Specifications Item 446 & 448 Asphalt Concrete Surface Course, Type 1, PG Items 446 and 448 Asphalt Concrete Surface Course, Type 1H Item 858 Asphalt Concrete Surface Course, 12.5 mm A & B (446 & 448) Item 446 Asphalt Concrete Intermediate Course, Type 1, PG Item 446 Asphalt Concrete Intermediate Course, Type 2, PG64-28 & PG Item 858 Asphalt Concrete Intermediate Course, 19 mm A & B (446) Item 448 Asphalt Concrete Intermediate Course, Type 1, PG64-28 & PG Item 858 Asphalt Concrete Intermediate Course, 9.5 mm A & B (448) Item 448 Asphalt Concrete Intermediate Course, Type 2, PG64-28 & PG Item 848 Asphalt Concrete Intermediate Course, 19 mm A & B (448) Item 301 Bituminous Aggregate Base, PG Item 302 Bituminous Aggregate Base, PG Item 407 Tack Coat Item 408 Prime Coat Smoothness Specifications 4-6

48 400 Flexible Pavement Design Procedures & Considerations Introduction Flexible pavement design is based on the use of the Structural Number. The Structural Number is a regression coefficient expressing the structural strength of a pavement required for given combinations of soil support (M R ), traffic loading, and terminal serviceability. Flexible pavements can be constructed with Superpave mixes, stone mastic mixes, contractor designed mixes, or ODOT mixes; however, regardless of the mix design method used for a flexible pavement, the ODOT/AASHTO method of pavement design calculates the same required Structural Number. Once the Structural Number is determined, the flexible buildup is determined by using the appropriate structural coefficient for ODOT specification materials. Alterations to ODOT s Construction and Material Specifications for asphalt concrete may require adjustments to the procedures described herein. Additional information on flexible pavement and proper construction practices can be found in the Manual of Procedures for Flexible Pavement Construction put out by the Office of Highway Management 401 Design Parameters Flexible pavement design is based on relatively few input parameters. Serviceability, traffic loading (ESAL), subgrade strength (M R ), reliability and overall standard deviation have all been discussed in Section 200. The appropriate structural coefficients for ODOT asphalt concrete material specifications are found in Figure Structural Number Determination Assembly of all the design input information is required prior to determination of design thickness. Structural Number is determined using the nomographs found in Figures and An example flexible pavement design is provided in Figure Ramps and Interchanges Ramps and Interchanges also require traffic and soils information for thickness design. However, some discretion must be used regarding the calculation of ESAL s. In general, use the lower functional classification factors for Reliability, B:C Ratio, and ESAL Conversion Factors. 403 Typical Section and Buildup Considerations Typical Section Design Regardless of the SN required, a buildup which includes an aggregate base (Item 304) will generally provide better performance than a full depth asphalt concrete buildup. The aggregate base is less sensitive to moisture than the subgrade is and it separates the pavement further from the subgrade. An aggregate base is recommended under all flexible pavements and particularly when the thickness of a full depth flexible design is very thin, approximately 5 inches (~130 mm) (SN ~ 1.8) or less. All surface and intermediate courses should be should be specified in 0.25 inch (~5 mm) increments. Items 301 and 302 should be specified in 0.5 inch (~10 mm) increments. Item 304 is typically placed at 6 inches (~150 mm) thick. The minimum thickness for Item 304 is 4 inches (~100 mm) and it should be specified in 1 inch (~25 mm) increments. When designing a flexible pavement, some consideration should be given to reducing the total number of separate lifts required. This can be done by keeping in mind the maximum and minimum lift thicknesses for all of the materials involved. Maximum and minimum lift thicknesses can be found either in the Construction and Materials Specifications book or Section 404 in this Manual. January

49 Flexible Pavement Design Procedures & Considerations Shoulder Buildups Shoulders are used to provide an area for the accommodation of disabled vehicles, for the lateral support of the base and surface courses, to improve the safety of a highway, and for future maintenance of traffic operations during maintenance and rehabilitation work. Shoulders for flexible pavements shall be constructed of the same materials and thicknesses as the mainline pavement for all Interstate, freeways, expressways, and other multi-lane facilities. This provides for the ability to have a hot longitudinal joint at the pavement-shoulder interface, provides a stable temporary pavement for maintenance of traffic lane shifts, and reduces the complexity of construction. Using other types of shoulders, such as bituminous surface treated, stabilized aggregate, or turf shoulders should be in accordance with Geometric Standards, discussed in the Location & Design Manual, Volume One - Roadway Design. Regardless of shoulder type, shoulder base and subgrade considerations should include directing drainage away from the pavement, rather than towards it. Examples of typical sections depicting flexible pavement with different types of shoulders are located in Figure Also refer to the Hydraulics Manual and Sample Plan Sheets Edge Course Design Item 304 Aggregate Base shall extend 6 inches (~150 mm) beyond the edge of the overlying bituminous base for bituminous base courses 9 inches (~225 mm) or less in thickness and 12 inches (~300 mm) beyond the edge for bituminous base courses thicker than 9 inches (~225 mm). Item 302 Bituminous Aggregate Base shall extend 6 inches (~150 mm) beyond the edge of the overlying Item 301 Bituminous Aggregate Base for Item 301 courses 9 inches (~225 mm) or less in thickness and 12 inches (~300 mm) beyond the edge for Item 301 courses thicker than 9 inches (~225 mm). Each course, regardless of the number of lifts required by the specifications, shall be designed and shown in a vertical plane. Any base course shall extend beyond the edge of the overlying intermediate course a distance equal to the thickness of the surface course plus the intermediate course or 4 inches (~100 mm), whichever is greater. The outside edge of the intermediate course shall be in alignment with the outside edge of the surface course. For concrete curbed sections, the asphalt concrete shall be paved to the face of the curb. Where the bottom courses of the asphalt pavement buildup lie below the depth of the curb base, those layers should be placed as a foundation for the curb, and should have the proper edge course design as discussed above Paved Shoulder Edge Course Design For shoulders that have the same buildup as mainline pavement refer to section Where shoulders are constructed with a buildup different than the mainline pavement, the outside edge of each course shall extend 6 inches (~150 mm) beyond the edge of the overlying course. 404 Lift Thickness and Specification Guidelines Items 402, 403, and 404 are no longer used on ODOT administered projects. ODOT asphalt concrete specifications contain gradation requirements for all items. For optimum performance of the pavement system, it is important to design the various lifts of asphalt concrete items in order to achieve maximum smoothness, durability, and densification. In order to do this, some constraints are required regarding maximum and minimum lift thicknesses in relation to the gradation of the item specified. Refer to ODOT specification and supplemental specification 858 for gradation differences and BP- 3.1 for feathering details. Of particular importance, it must be understood that by following the guidelines provided herein, typical sections which require heavy mix designs should avoid specifying overlay thicknesses between 2.5 inches (~65 mm) and 3.25 inches (~83 mm). Reference is made to Appendix B - Pavement Guidelines for Treatment of High Stress Locations. January

50 Flexible Pavement Design Procedures & Considerations All Item 446 & 448 Type 1 and Type 2 Courses The only difference between 446 and 448 is the way ODOT accepts the material during construction. These materials are identical as they come out of the plant. Because Item 446 carries a density requirement for acceptance criteria, it is important to understand that Item 446 must only be specified where a uniform thickness is used. The following guidelines are to be used for the determination of asphalt concrete material specification: Specify 446 for all projects which require a quantity of greater than 500 cubic yards (~500 cubic meters) of Type 1H surface course. Specify 446 for all multi-lane resurfacing and rehabilitation projects. Specify 446 for all projects where included quantities (Type 1 and Type 2) exceed 2000 cubic yards (~1500 cubic meters). Specify 448 for all projects where 446 is not required. Superpave shall be implemented in accordance with direction provided by the Division of Engineering Policy. For projects which require 446, and only use variable thickness at bridges and ramps in order to taper down to the required elevation, it is considered good practice to specify only the 446 Item. ODOT construction and testing staff will only test the areas which are constructed as uniform thickness, and skip the testing of the variable thickness courses. This will eliminate a pay item and other complications. Where Item 446 is specified for the surface course, all Type 1 and Type 2 material specified should be 446, except where a uniform lift thickness is not possible Superpave Specifications Superpave mixes are similar to 446 and 448 mixes except the mix design procedures as required in ODOT CMS 441 are modified by Supplemental Specification 858. Type A and B requirements are found in SS 858. They control gradation bands and aggregate angularity. Type A has higher crush requirements that may mean the importation of aggregate in some areas of the state. This will raise product cost where districts have had good performance from locally available aggregates. Type B has more restrictive gradation bands but lower crush requirements. Gradation requirements of Type B mix will closely resemble Type 1H mix under 441. District testing and construction personnel knowledgeable in materials should be consulted prior to selection of Type A or B. Pay descriptions for Superpave items contain a reference to the maximum aggregate size used in the mix. Accordingly, the 9.5 mm, 12.5 mm, and 19.0 mm aggregate sizes are used for Superpave mix types. This reference to the maximum aggregate size replaces the reference to Type 1, Type 1H, and Type 2, respectively, used in nonsuperpave specifications, and has nothing to do with any other measurement Item 446 & 448 Asphalt Concrete Surface Course, Type 1, PG64-22 This item is intended to be used as a surface course for Medium or Light traffic (see PN 417 and 418). Lift thickness can vary between 1.25 inches (~32 mm) and 1.5 inches (~38 mm). Lift thickness can be reduced to 1 inch (~25 mm), but must be a uniform thickness if 446 is specified. Where Item 446 is specified for the surface course, all Type 1 material specified should be Item 446 material, except where a uniform lift thickness is not possible. Item 446 is to be specified only in uniform thickness Items 446 and 448 Asphalt Concrete Surface Course, Type 1H All projects which require a quantity greater than 500 cubic yards of Type 1H surface course shall specify Item 446 for the surface course. Item 446 is to be specified only in uniform thickness. This item is intended to be used as a surface course for a Heavy mix design (ADTT>1500, see PN 416). Type 1H mix is designed for maximum rut resistance at 1.5 inches (~38 mm) thick. Type 1H is generally the most expensive mix and an January

51 Flexible Pavement Design Procedures & Considerations increased thickness may not be economical. In special situations where an intermediate course is not possible, Type 1H may be specified up to a maximum of 2.5 inches (~65 mm). A 1H course cannot be placed properly at a thickness less than 1.5 inches (~38 mm). Durability and constructability problems will result. Best practice is to use 1.5 inches (~38 mm). A Type 1H will not have a performance grade (PG) asphalt cement specification. All 1H mixes are designed using an SBS or SBR polymer modified asphalt cement. For more detailed information see PN and SS Item 858 Asphalt Concrete Surface Course, 12.5 mm A & B (446 & 448) This Item is the Superpave version of Type 1H. The requirements of Section apply Item 446 Asphalt Concrete Intermediate Course, Type 1, PG64-22 This item is to be used as an intermediate course in pavement overlay situations where the total overlay thickness is less than 3 inches (~75 mm). A Type 1 Intermediate Course is required because of the thin intermediate layer. Lift thickness for this item can be as thin as 1 inch (~25 mm) and as thick as 1.5 inches (~38 mm). Item 446 is to be specified only in uniform thickness. Because the grading of Type 1 mixes typically exhibit less stability than that of a Type 1H or a Type 2 mixture, caution is advised when determining the use and thickness of this item, such that deformation is avoided. Best practice is to include some planing of the existing surface to allow a Type 2 material to be used for the intermediate course. This item is not to be used in combination with a Type 1H surface course. Where Item 446 is specified for the surface course, all Type 1 material specified should be Item 446 material, except where a uniform lift thickness is not possible Item 446 Asphalt Concrete Intermediate Course, Type 2, PG64-28 & PG64-22 This item is intended to be used as an intermediate course. The gradation of this mix requires the lift to be at least 1.75 inches (~45 mm) thick. In special circumstances it is possible to allow this lift to be as thin as 1.5 inches (~38 mm), but this is discouraged. Item 446 is to be specified only in uniform thickness. Caution is advised when determining the use of and the thickness of this Item. ODOT CMS specifies a maximum compaction lift of 3 inches (~75 mm). For a required layer of say 3.5 inches (~90 mm), the contractor will automatically place the material in two lifts of 1.75 inches (~45 mm). It is best to avoid specifying layers between 3 inches (~75 mm) and 3.5 inches (~90 mm) due to the 1.75 inch (~45 mm) minimum lift thickness requirement. For most situations, the total thickness should not exceed 4.5 inches (~115 mm), as it would be better to introduce the additional thickness into the 301 or 302 or even the 304 base(s). Specify PG64-28 for projects which have a Type 1H surface mix, otherwise specify PG Item 858 Asphalt Concrete Intermediate Course, 19 mm A & B (446) This Item is the Superpave version of Item 446 Asphalt Concrete Intermediate Course, Type 2, PG The requirements of Section apply Item 448 Asphalt Concrete Intermediate Course, Type 1, PG64-28 & PG64-22 The intent of this item is for a scratch course. Uniform lift thickness for this item can be as thin as 1 inch (~25 mm) and as thick as 1.5 inches (~38 mm). This item can be used as a variable thickness course. For some rare occasions, when this lift is used as a leveling or wedge course, it may be practical to stretch the lift thickness past the 1.5 inch (~38 mm) limit. For situations where the variability of the course thickness is excessive, say 0 inches to 2 inches (0 mm to ~50 mm), consideration should be given to pavement planing to allow for the use of a Type 2 mix which provides more stability than a Type 1mix. This item can be tapered to 0 inches (0 mm). For projects which require 446 specifications, but need this type of a leveling or wedge, there is nothing wrong with placing a 448 Intermediate, Type 1 under a 446 Surface. However, this item is not to be used as uniform thickness layer underneath a Type 1H layer. Where Item 446 is specified for the surface course, all Type 1 material January

52 Flexible Pavement Design Procedures & Considerations specified should be Item 446 material, except where a uniform lift thickness is not possible. Specify PG64-28 for projects which have a Type 1H surface mix, otherwise specify PG Item 858 Asphalt Concrete Intermediate Course, 9.5 mm A & B (448) This Item is the Superpave version of Item 448 Asphalt Concrete Intermediate Course, Type 1, PG The requirements of Section apply Item 448 Asphalt Concrete Intermediate Course, Type 2, PG64-28 & PG64-22 The intent of this item is the same as for Item 446 Asphalt Concrete Intermediate Course, Type 2 (Section 404.6). However, there is a difference. This item can also be used as a variable thickness course. For some rare occasions, when this lift is used as a leveling or wedge course, it may be practical to stretch the maximum recommended thickness past the 4.5 inch (~115 mm) limit. As for the minimum lift thickness, this item can be specified to 0 inches (0 mm). For projects which require 446 specifications, but need this type of a leveling or wedge, it is acceptable to place a 448 Intermediate, Type 2 under a 446 Surface Type 1. However, for high traffic volumes, this practice should be avoided, if possible, to minimize pavement densification under traffic. Specify PG64-28 for projects which have a Type 1H surface mix, otherwise specify PG Item 848 Asphalt Concrete Intermediate Course, 19 mm A & B (448) This Item is the Superpave version of Item 448 Asphalt Concrete Intermediate Course, Type 2, PG The requirements of Section apply Item 301 Bituminous Aggregate Base, PG64-22 This item is to be used in conjunction with both a surface and intermediate course. The gradation of this mix requires the lift to be at least 3 inches (~75 mm) thick. For most situations, this material should have 304 underneath, and a minimum of 3 inches (~75 mm) of surface and intermediate course above. In special circumstances it is possible to allow this lift to be as thin as 2.5 inches (~65 mm), but this is discouraged. This item may be placed in variable thicknesses. ODOT CMS specifies a maximum compaction lift of 6 inches (~150 mm). For a required layer of say 7 inches (~180 mm) the contractor will automatically place the material in two lifts of 3.5 inches (~90 mm). For most situations, the total thickness should not exceed 10 inches (~250 mm), as it would be better to introduce the additional thickness into a 302 and/or a 304 base(s). This material can handle traffic during construction due to phasing but care should be taken to minimize high traffic volume contact. In high traffic volume situations, an intermediate course is preferred for maintenance of traffic, particularly over the winter Item 302 Bituminous Aggregate Base, PG64-22 This item is to be used in conjunction with both a surface and intermediate course. This mix was developed for use with thick flexible pavements where high volume truck traffic exists. When lift thicknesses and maintenance of traffic operations allow, Item 302 is preferred over Item 301. The gradation of this mix requires the lift to be at least 4 inches (~100 mm) thick. ODOT CMS specifies a maximum compaction lift of less than 8 inches (200 mm). For a required layer of exactly 8 inches (~200 mm) the contractor will automatically place the material in two lifts of 4 inches (~100 mm). This item may be placed in variable thicknesses. For most situations, this material should have 304 underneath, and a minimum of 3 inches (~75 mm) of surface and intermediate course above. It is not necessary to put a 301 course above a 302 course. Placement of 301 below 302 is illogical. Item 302 should not be used for maintenance of traffic for more than approximately 60 days and never over the winter. If it is necessary to maintain traffic for more than 60 days or over winter, the top 3 inches (75 mm) of the 302 could be changed to 301, or more preferable, the project should be scheduled to allow the intermediate course to be placed for maintenance of traffic. January

53 Flexible Pavement Design Procedures & Considerations Item 407 Tack Coat A tack coat is used to glue an asphalt layer to the layer below. Tack coats are required anytime a surface course is placed on an intermediate course (CMS ). Tack coat is recommended anytime new asphalt is being placed on an existing surface with two exceptions. Tack coat should not be used under a bondbreaker layer for an unbonded concrete overlay. Tack coat also should not be used on rubblized concrete. Actual application rates of tack coat are set in the field. The most common application rate used for estimating quantities is 0.75 gallons per square yard (0.34 L/m 2 ). Estimated application rate of tack for surface courses placed on intermediate courses is 0.04 gallons per square yard (.018 L/m 2 ) Item 408 Prime Coat Prime coats are applied to Item 304 Aggregate Base to prevent binder from the asphalt from being absorbed into the 304 or under a free draining base to prevent erosion of the 304. Prime coats are required under all free draining bases, see Section In the absence of a free draining base, a prime coat is recommended anytime the thickness of the Bituminous Aggregate Base (Item 301 or 302) is less than or equal to the thickness of the 304. For thicker pavements a prime coat may not be necessary but is still optional. Application rate for prime coat is always 0.4 gallons per square yard (1.8 L/m 2 ). 405 Smoothness Specifications Incentive/disincentive for smoothness is specified using Proposal Note Surface Smoothness Requirements. The Note is to be used on projects which have a 446-type surface mix, either conventional or Superpave. The traffic volume should be either heavy or medium (see PN 416 and 417). The project should be greater than one center-line mile (~1.6 center-line km) of divided highway with two or more lanes per direction. On resurfacing projects, the total thickness of new asphalt must be at least 4 inches (~100 mm) if the existing surface is not planed, or 3 inches (~75 mm) if the existing surface is planed. When placing an overlay directly on concrete which has either never been overlayed or has had the existing overlay removed, the total thickness of asphalt must be at least 4 inches (~100 mm). The exception to this is projects which involve building a new composite pavement do not require the 4- inch (~100 mm) minimum. January

54 400 Flexible Pavement Design Procedures & Considerations List of Figures Figure Date Subject January 1999 Flexible Pavement Structural Coefficients January 1999 Flexible Pavement Design Example January 1999 Flexible Pavement Design Chart Segment January 1999 Flexible Pavement Design Chart Segment January 1999 Bituminous Surface Treated Shoulder and Stabilized Aggregate Shoulder Typical Sections

55 Flexible Pavement Structural Coefficients January 1999 Reference Section 401 ASPHALT CONCRETE STRUCTURAL COEFFICIENTS Material English Coefficient Metric Coefficient Items 446, Asphalt Concrete Surface Courses Items 446, Asphalt Concrete Intermediate Courses Items 301, Bituminous Aggregate Base Courses Item Special - SMA mixes, Superpave mixes Cracked & Seated Plain Concrete Pavement Existing Asphalt Concrete - old, oxidized, & weathered Item Aggregate Base Item Special - Rubblize & Roll Existing Concrete Pavement Items 306, 307, Free Draining Base Layers Asphalt Concrete Drainage Factor = 1.0

56 Flexible Pavement Design Example Page January 1999 Reference Section 402 Example - Flexible Pavement Design Givens: Number of Lanes: 4 Functional Classification: Rural Principal Arterial 1998 Traffic: 14,800 ADT 2018 Traffic: 23,360 ADT 24 hour truck % 10 Year Completed: 2000 Soil Classification: Liquid Limit = 45 Plasticity Index = 12 % Passing #200 sieve = 70 Problem: Solve for the Structural Number of the Flexible Buildup Solution: Step 1 - Determine the Group Index Number (G.I.) Using Figure In chart A, solve for the Partial Group Index using the 70 % Passing No. 200 Sieve and the Liquid Limit (L.L.) Of 45. G.I. from Chart A = 7.9. In Chart B, solve for the Partial Group Index using the 70 % (55 or more) Passing No. 200 Sieve and the Plasticity Index of 12. G.I. from Chart B = 0.8. The total G.I. is 7.9 plus 0.8 or 8.7 (Rounded to 9). Step 2 - Determine the Subgrade Resilient Modulus (M R ) using Figure Using a G.I. of 9 from Figure (Step 1), the California Bearing Ratio (CBR) is 6 (Rounded). The CBR is used in the following formula to determine the Resilient Modulus. M R = 1200 X 6 = 7200 psi.

57 Flexible Pavement Design Example Page January 1999 Reference Section 402 Step 3 - Determine the 18 Kip Equivalent Single Axle Loading (ESAL) Since the project is expected to begin carrying traffic in the year 2000, the traffic period would be 2000 to 2020, with a mid-year of 2010 and an interpolated ADT of 19,936. Directional Distribution, D = 50 % (Figure 202-1) Lane Factor =.90 (Figure 202-1) B:C Ratio = 4:1 (Figure 202-1) B factor = 1.51 (Figure 202-1) C factor = 0.66 (Figure 202-1) ESAL's from B trucks: 19,936(0.10)(0.50)(0.90)(4/5)(1.51) = 1,083.7 ESAL ESAL's from C trucks: 19,936(0.10)(0.50)(0.90)(1/5)(0.66) = ESAL Total ESAL s 1,202.1 ESAL per day Design Period ESAL s = 1,202.1 X days/yr. X 20 year = 8,781,639 say 8.8 x 10 6 ESAL Step 4 Determine the Design Structural Number (SN) using Figures and In Figure 402-2, solve for the Match Line Number using the following information: Reliability = 85 % (Figure 201-1) Overall Standard Deviation = 0.49 (Figure 201-1) 18-kip Single Axle Loads = 8.8 x 10 6 ESAL (Step 3) Resilient Modulus = 7,200 psi (Step 2) The resulting Match Line Number of 39 is then used in Figure 402-3, along with the Design Serviceability Loss of 2.0 (Figure 201-1), to solve for the Design Structural Number (SN). Therefore: Design Structural Number (SN) = 4.50 Step 5 Design the typical section using the layer coefficients found in Figure The total SN for the pavement buildup shall equal or exceed the SN (SN = 4.5) determined from Figure

58 Flexible Pavement Design Example Page January 1999 Reference Section 402 By checking the current year Average Daily Truck Traffic (ADTT, see PN 416), determine the type of surface mix required. 14,800 X 0.10 = 1,480 trucks < 1,500 trucks (see Note) Therefore, use a Type I surface course at a minimum lift thickness of 1.25 inches. The following buildup is not the only solution, but will satisfy the required SN: Material Thickness Coefficient SN 448 Asphalt Concrete Surface Course, Type 1, PG Asphalt Concrete Intermediate Course, Type 2, PG Bituminous Aggregate Base 304 Aggregate Base 1.25" 1.75" 7.5" 6" " 4.51 Note: 1,480 trucks per day (ADTT) is so close to 1,500 that it may be appropriate to specify a heavy mix design. Also see PN 416, and Appendix B

59 Flexible Pavement Design Chart Segment January 1999 Ref. Section & Figure 402, 402-1(step 4)

60 Flexible Pavement Design Chart Segment January 1999 Ref. Section & Figure 402, 402-1(step 4)

61 Bituminous Surface Treated Shoulder and Stabilized Aggregate Shoulder Typical Sections January 1999 Reference Section 205.1

62 Table of Contents 500 Pavement Design Procedures for Minor Rehabilitation Introduction Deflection Measuring Equipment Dynaflect Falling Weight Deflectometer Deflection Testing and Analysis General Analysis Edwards Ratio W 5 vs. CBR Load Transfer Joint Support Ratio Factors Affecting Deflections Loading Climate Pavement Conditions Overlay Design Procedure Introduction Rigid Pavements Flexible Pavements Composite Pavements Brick Pavements Minor Rehabilitation Strategies Asphalt Considerations Milling Brick Pavements Pavement Repair Rigid and Composite Pavements Flexible Pavements Brick Pavements Reflective Crack Control Sawing and Sealing Fabrics and Geogrids Concrete Pavement Restoration Geometric Issues Pavement Widening Rigid Pavement Flexible Pavement Composite Pavement...5-8

63 500 Pavement Design Procedures for Minor Rehabilitation Introduction Minor rehabilitations should occur when the pavement has deteriorated beyond the point at which preventive maintenance is effective but does not yet require major rehabilitation. Minor rehabilitations usually consist of some combination of milling, repair, and overlay. ODOT designs minor rehabilitation overlays using a deflectionbased procedure and twelve-year traffic projections. 501 Deflection Measuring Equipment Deflection measuring equipment imposes a load on the pavement and measures the response. The deflections can be correlated to the structural condition of the pavement and the subgrade. Designers can interpret the deflections and provide recommendations for pavement rehabilitation. ODOT has two kinds of deflection measuring equipment or Non-Destructive Testing (NDT) devices: the Dynaflect, and the Falling Weight Deflectometer. Both are described below; however, this manual is written specifically for use with the Dynaflect Dynaflect The Dynaflect is an electro-mechanical device used for measuring pavement deflection. It is trailer-mounted and can be towed by a standard vehicle. A static weight of 2000 pounds (~908 kg) is applied to the pavement through a pair of 4-inch wide by 16-inch (~406 mm) diameter rubbercoated steel wheels placed 20 inches (~508 mm) apart. Two counter-rotating eccentric weights produce a dynamic force of 1000 pounds (~454 kg), peak-to-peak, at a frequency of eight cycles per second. The dynamic force is superimposed on the static force and the deflections are measured by five velocity transducers (geophones). The first geophone is located between the steel wheels with the rest spaced twelve inches (~305 mm) apart. The deflections are recorded on a computer in the tow vehicle Falling Weight Deflectometer The Falling Weight Deflectometer (FWD) is an impact load response device used to measure pavement deflection. The impact force is created by dropping a weight of 110, 220, 440, or 660 pounds (~50, 100, 200, 300 kg) from a height of 0.8 to 15 inches (~20 to 380 mm). By varying the drop height and weight, a peak force ranging from 1500 to 24,000 pounds (~6.7 to kn) can be generated. The load is transmitted to the pavement through a loading plate, 11.8 inches (~300 mm) in diameter, to provide a load pulse in the form of a half sine wave with a duration from 25 to 30 ms. The actual magnitude of load applied may depend on the stiffness of the pavement and is measured by a load cell. The deflections are measured by seven velocity transducers. One transducer is located at the center of the loading plate while the remaining six can be placed at locations up to 7.4 feet (~2.25 m) from the center. The deflections are recorded on a computer located in the tow vehicle. 502 Deflection Testing and Analysis General Deflection measurements taken when the subgrade is frozen are meaningless for design. The testing season in Ohio runs approximately April through November. Requests for Dynaflect testing should be made to the Research and Development Section of the Office of Materials Management with a copy of the request to the Pavement Design Section in the same Office. Requests are honored on a first-come, first-served basis, subject to scheduling considerations. Requests made too late in the season may not be tested until the following year. Research testing needs take priority during many of the summer months. The best time to submit requests is just prior to and early in the testing season. All requests must include the exact limits of the project using the current English straight-line diagrams issued by the Office of Technical Services, even for projects being developed in metric units. Deflection measurements represent a snapshot of the pavement at that time. As the pavement continues to deteriorate, the snapshot changes. Therefore, deflection data should not be obtained more than four years prior to construction. If the project is delayed such that the data will be more than four-years old, new deflection measurements should be requested and the design checked against the new measurements to ensure validity. January

64 Pavement Design Procedures for Minor Rehabilitation Analysis Deflection measurements yield a great deal of information about the pavement when properly interpreted. This Manual is not intended to make the reader an expert in analyzing deflection data. A training course is available which discusses the data analysis in much greater detail Edwards Ratio One of the more useful parameters derived from the Dynaflect data is called the Edwards Ratio. Named after William F. Edwards, former Bureau Chief of Research and Development at ODOT. The Edwards Ratio states that if the w 1 sensor reading divided by the w 5 sensor reading is greater than three, the pavement is acting as a flexible pavement and should be analyzed as such. If it is less than three, the pavement is acting as a rigid pavement and should be analyzed as such. This is very useful when trying to decide how to analyze a brick pavement or an existing break & seat or crack & seat W 5 vs. CBR The w 5 sensor provides an estimate of the subgrade strength. The chart in figure shows the relationship between the average w 5 sensor reading plus two standard deviations and the CBR value. The average w 5 reading and the standard deviation are given on the Dynaflect printout Load Transfer The Load Transfer factor can indicate joints which have deteriorated and are no longer effectively transferring the load. Load Transfer factors less than 0.70 indicate poor load transfer. Factors greater than 0.70 do not necessarily indicate good joints. If the pavement is warm, the joints may be locked up and showing better load transfer than actually exists. The Load Transfer factor is the w 2 sensor divided by the w 1 sensor, both from the joint approach reading. A graph of Load Transfer values is given by the UTPLOT program (Section 503.1) Joint Support Ratio The Joint Support Ratio is another measure of the joint s effectiveness. Joint Support Ratio is the w 1 sensor from the joint leave reading divided by the w 1 sensor from the joint approach reading. Joint Support Ratios between 0.50 and 1.50 are considered good. Ratios outside this range indicate probable voids under the joint. Voids are also likely anytime the w 1 sensor reading is above 1.0. The UTPLOT program provides a graph of the Joint Support Ratio Factors Affecting Deflections The major factors that influence deflections include loading, climate and pavement conditions. These factors must be carefully considered when conducting nondestructive tests Loading The magnitude and duration of loading have a great influence on pavement deflections. It is desirable that the NDT device applies a load to the pavement similar to the actual design load, e.g., a 9000 pound (~4086 kg) wheel load. Unfortunately, not every commercially available NDT is capable of simulating the design load. Some can simulate the magnitude of the design load but not its duration or frequency. Due to the nonlinear or stress-sensitive properties of most paving materials, pavement deflections are not proportional to load. Test results obtained for light loads must be extrapolated to those for heavy loads. Because extrapolation may lead to significant error for nonlinear paving materials, the use of NDT devices that produce loads approximating those of heavy truck loads is recommended by most researchers. In 1989, FHWA/ODOT published Technical Report No. FHWA/OH-89/020 titled: Implementation of a Dynamic Deflection System for Rigid and Flexible Pavements in Ohio. This research study looked into the non-linearity problems associated with NDT using light loading as compared to normal truck loads. The relevant conclusion was: on the average, pavement deflections obtained by the Dynaflect and the FWD correlated quite well and pavement non-linearity was not as significant as was anticipated Climate Temperature and moisture are the two climatic factors that affect pavement deflections. For asphalt pavements, higher temperatures cause the asphalt binder to soften and increase deflections. For concrete pavements, temperature in the form of overall change or thermal gradient has a January

65 Pavement Design Procedures for Minor Rehabilitation significant influence on deflections near joints and cracks. The slab expands in warmer temperatures causing tighter joints and cracks and resulting in greater efficiency of load transfer and smaller deflections. The curling of the slab due to temperature gradients can cause a large variation in measured deflections. Measurements taken at night or early morning, when the top of the slab is colder than the bottom, will result in higher corner and edge deflections than those taken in the afternoon, when the top of the slab is much warmer than the bottom. The season of the year has a great effect on deflection measurements. In cold regions, four distinct periods can be distinguished. The period of deep frost occurs during the winter season when the pavement is the strongest. The period of spring thaw starts when the frost begins to disappear from the pavement system and the deflection increases rapidly. The period of rapid strength recovery takes place in early summer when the excess free water from the melting frost leaves the pavement system and the deflection decreases rapidly. The period of slow strength recovery extends from late summer to fall when the deflection levels off slowly as the water content slowly decreases. For pavements that do not experience freeze-thaw, the deflection generally follows a sine curve with the peak deflection occurring in the wet season when the moisture contents are high Pavement Conditions Pavement conditions have significant effects on measured deflections. For asphalt pavements, deflections obtained in areas with cracking and rutting are normally higher than those free of distress. For concrete pavements, voids beneath the concrete slabs will cause increased deflections, and the absence or deterioration of load transfer devices will affect the deflections measured on both sides of the joint. 503 Overlay Design Procedure Introduction The overlay design procedure for minor rehabilitations is based on the UTOVER computer program. A great deal of preparatory work and research must take place before the computer program is run. The Dynaflect readings must be available (Section 502). The traffic projections must be completed (Section 202). Finally, the history of the pavement must be known. The history is required to determine the actual buildup of the pavement at the time the Dynaflect measurements were taken. There are many sources for this information such as historical plans, the pavement management system database, the joint repair database, etc. On past overlay projects where existing asphalt was milled, it is necessary to determine the depth of milling or at least a reasonable estimate. The UTOVER program requires the total thickness of asphalt and/or concrete at the time the Dynaflect readings were taken. If the thickness changes within the project, the user must split the data and run UTOVER separately for each of the different thicknesses. Once all the required information is collected, the first step is to run the UTPLOT.BAT program. UTPLOT converts the raw Dynaflect file to a format which can be read by UTOVER. Next is to run the UTOVER.EXE program. The input files for UTOVER are the output files created by UTPLOT and not the raw Dynaflect file. Most of the user inputs for UTOVER are selfexplanatory and many provide default values. Some inputs are common to all pavement types: the title is the users choice, the design traffic input comes from the ESAL99 program (Section 202.3), reliability factors are given in Figure 201-1, the traffic standard deviation is always the default value of 0.10, the file name containing the Dynaflect data is one of the files created by UTPLOT, and the output file name is the users choice. Inputs specific to each pavement type are discussed in the following sections. The information given here is not intended to fully explain the UTOVER procedure or Dynaflect analysis. A training course is available which goes over the procedures in detail. All of the inputs and outputs for UTOVER are exclusively in English units Rigid Pavements Rigid pavement refers to all types of exposed concrete pavement with no asphalt on top. The minimum overlay thickness for rigid pavements is three inches. Pavements which require an overlay of about one inch or less are candidates for diamond grinding instead of an overlay. January

66 Pavement Design Procedures for Minor Rehabilitation Most of the rigid pavement inputs to UTOVER use the default values. The thickness of the existing pavement is obtained from the history. Use the default value for Poisson s Ratio of the existing concrete. Use the default values for elastic modulus, initial PSI, terminal PSI, modulus of rupture, and the drainage coefficient. The load transfer coefficient (J) is dependent on the specifics of the existing pavement. A list of J- factors for existing pavements is given in Figure A rigid pavement with the majority of the joints replaced with flexible repairs, should use a J- factor for a pavement with no load transfer at the joints Flexible Pavements Flexible pavements are made up entirely of asphalt with or without an aggregate or macadam base. Previously rubblized pavements are considered flexible pavement. Previous break & seat and crack & seat projects may be flexible pavement but are more likely acting as composite pavement. The Edwards Ratio can help in determining pavement type in questionable cases. Most of the inputs for flexible pavement require the user to enter values. The whole thickness of flexible pavement above subgrade is exactly what the name implies: the thickness of the aggregate base, macadam base, or rubblized concrete plus the entire thickness of asphalt on top. The thickness of the surface AC layer is required for temperature adjustment. It is not a sensitive input. Best practice is to use the thickness of the existing surface and intermediate courses combined. Pavement surface temperature is recorded on the Dynaflect printout. Where additional temperatures were recorded for the same data, a weighted average should be used. The 5-day mean air temperature should be obtained from meteorological records, if available. In the absence of actual temperature data, the morning pavement surface temperature should be used as the basis for the 5-day mean temperature. Some adjustment is allowed if the user is aware of specific temperature conditions in the days just prior to the Dynaflect readings. Initial and terminal PSI are always 4.5 and 2.5, respectively Composite Pavements Composite pavements are concrete overlaid with asphalt. Most old break & seat and crack & seat projects should be analyzed as composite pavements. Any asphalt-surfaced road with some sort of concrete underneath, that is acting like a rigid pavement according to the Edwards Ratio, should be analyzed as a composite pavement. The inputs for composite pavement are nearly identical to rigid pavement with the addition of asphalt on top (Section 503.2). Thickness of existing AC layer is the thickness of all the asphalt on top of the concrete. The default values should be used for Poisson s Ratio and the resilient modulus of the asphalt. The thickness of existing PCC slab is obtained from the history or coring. Use default values for Poisson s Ratio, new concrete elastic modulus, initial PSI, terminal PSI, new concrete modulus of rupture, and drainage coefficient. The load transfer coefficient (J) is dependent on the specifics of the existing pavement. A list of J-factors for existing pavements is given in Figure A composite pavement with the majority of the joints replaced with flexible repairs, should use a J-factor for a pavement with no load transfer at the joints Brick Pavements Most brick pavements in Ohio were built on a concrete base and have since been overlayed with asphalt and thus are a special kind of composite pavement. The UTOVER program was not designed for use on brick pavements. The Edwards Ratio can help the user decide which type of pavement to use to analyze the brick. When inputting the thicknesses, it is up to the user to decide if the bricks count as concrete or as asphalt. Since brick pavements occur mostly in urban areas, there are likely to be geometric problems such as curb reveal, driveways, etc. A possible solution is to design a crack and seat overlay (see Section 600) with removal of both the asphalt and the bricks. This should only be done if the section has been cored to determine the condition and thickness of the existing concrete. The actual cracking and seating operation should not be January

67 Pavement Design Procedures for Minor Rehabilitation performed as the concrete is likely already well cracked. This method merely eliminates the need to run UTOVER on a brick pavement which it was not intended for and can sometimes result in excessive overlay thicknesses. 504 Minor Rehabilitation Strategies As stated before, minor rehabilitations generally consist of some combination of milling, repair, and overlay. The structural overlay thickness needed is determined from the Dynaflect and the UTOVER program. Even if UTOVER says that no additional structure is needed, an overlay may still be required to correct functional deficiencies. The thickness of a functional overlay is selected based on factors such as milling depth, lift thickness requirements, vertical clearance, curb reveal, etc. A functional overlay with milling should never result in thinner pavement than existed beforehand. The other minor rehabilitation actions are at the designer s discretion based on the condition of the pavement. The actions selected should be those required to reach the full design period for minor rehabilitation projects Asphalt Considerations All asphalt items used in minor rehabilitation overlays should conform to the guidelines given in Section 404. Prior to completion of the plans, all asphalt items specified should be discussed with the District Engineer of Tests or his designee. This is important to ensure proper binder grades and mix specifications are specified. A minimum of 3 inches (~75 mm) of asphalt is required over any concrete or brick surface Milling Milling is always recommended. A milled surface allows for mechanical interlock between the existing pavement and the overlay which helps prevent rutting and debonding. Milling removes the old, raveled, oxidized asphalt which, if left in place, would be a weak layer in the pavement structure and would tend to hold water due to the lower binder content. Milling reduces the overall elevation increase and thus helps reduce geometric problems. Milling removes ruts and other irregularities and provides a level surface for the contractor to achieve proper density for 446 mixes. When old asphalt is removed, it is necessary to replace the structure removed with an equivalent structure of new asphalt. The structural ratio of new asphalt to old asphalt used in Ohio is 2:3. For example, if 3" (~75 mm) of asphalt are removed, 2" (~50 mm) of asphalt are required to replace the lost structure. Any required structural overlay is then placed in addition to the 2 inches (~50 mm). This ratio should not be used to make major reductions in the pavement thickness. In virtually all cases, the pavement thickness after rehabilitation should be equal to or greater than the thickness prior to rehabilitation. On composite pavements, including brick, if all the asphalt is removed down to the concrete, or bricks, the minimum overlay thickness for rigid pavements of 3 inches (~75 mm) applies. When milling down to a concrete surface, consideration should be given to lightly scarifying the top of the concrete if the total overlay is less than 5 inches (~125 mm) thick. The scarification should be specified by plan note. The roughened surface increases the bond between the asphalt and the concrete, therefore reducing the chances of rutting and debonding Brick Pavements When milling asphalt over an existing brick base, it is recommended to leave about two inches (~50 mm) of asphalt on the bricks. Milling any closer can easily dislodge the bricks and pull them up with the asphalt. Dislodged bricks should be quickly repaired, preferably using Asphalt Concrete (Items 301 or 448 Type 2), to prevent adjacent bricks from moving. Repairs should be made prior to running any traffic over the area, including construction traffic Pavement Repair Rigid and Composite Pavements Pavement repairs in rigid and composite pavements most often occur at transverse joints and cracks and are generically referred to as joint repairs. Joint repairs can be made using either concrete or asphalt. The repairs can be at existing transverse joints or transverse cracks or any other place which requires full-depth repair. Rigid repairs per BP-2.5, using Item 255 Full Depth Pavement Removal and Rigid Replacement are recommended in almost every case. Prior to repair, coring is recommended to determine if solid January

68 Pavement Design Procedures for Minor Rehabilitation concrete exists near the joints to dowel into. Where solid concrete does not exist, flexible repairs are an option but more likely the pavement requires major rehabilitation. Only coring can reveal if the concrete near the joints is solid, Dynaflect analysis and visual inspection of the surface cannot reveal this. Joint repair is considered economical for repair quantities up to ten percent of the pavement surface area. When more than ten percent repair is needed, a more thorough investigation is warranted. If not already done, the pavement should be cored to better determine exact repair needs. The required overlay thickness needs to be examined and the possibility of major rehabilitation should be considered. It should be remembered that minor rehabilitations are intended to last twelve years, not twenty. It may not be necessary to repair every joint, especially if the pavement is to receive a thick overlay. When estimating repair quantities, it is important to correctly calculate the pavement sawing quantities. Transverse saw cuts are required across the pavement at the limits of the repair. A saw cut is also required along any tied longitudinal joint. For a typical six foot repair in one twelve foot wide lane on a four-lane divided highway with asphalt shoulders, the total sawing quantity would be 12' +12' +6' = 30' (3.6 m +3.6 m +1.8 m = 9 m). In the past, due to concerns over pressure in concrete pavements, Type D pressure relief joints (per BP-2.4) were sawed at approximately foot (~300 m) intervals in many concrete pavements around the state. This not only relieved the pressure in the pavements but allowed the midpanel cracks to open up and thus lose aggregate interlock required for load transfer. These Type D joints should be repaired full depth with rigid joint repairs whenever they are encountered. To guard against pressure damage to the bridges, a Pressure Relief Joint, Type A per BP-2.3, may be installed at the approach slabs. Some concrete pavements have had joints repaired with full depth flexible repairs. These asphalt repairs tend to hump up as the concrete expands, forming mini speed bumps which can be very detrimental to the ride and can be a maintenance headache. When a majority of the joints have been repaired with asphalt, it is generally impractical to re-repair them with concrete. However, if there are only a few flexible repairs or if the concrete is in excellent condition except for the flexible repairs, it may be practical to replace all the flexible repairs with rigid repairs Flexible Pavements Flexible pavements may require full-depth repair due to potholes, severe alligator cracking, transverse thermal cracks, etc. Repairs in flexible pavements are done using Item 253 Pavement Repair. As with rigid and composite pavements, when repair quantities exceed about ten percent, further investigation is warranted and major rehabilitation should be considered. For construction purposes, the minimum practical repair size is 2 feet by 2 feet (~0.6 m x 0.6 m). Transverse thermal cracks are similar to transverse joints in concrete pavement. As flexible pavements expand and contract with temperature, if the binder is too stiff the pavement will crack. These cracks can be random or can be regularly spaced just like joints in concrete. Thermal cracks are full-depth cracks through the entire thickness of the pavement and must be repaired full depth to correct them and prevent them from reflecting through the surface Brick Pavements Brick pavements built on a concrete base typically do not have joints but often require full-depth repair. Full-depth repairs should be made using Item 305 Concrete Base, As Per Plan. A plan note needs to be written to handle all project specific concerns. In general, the note should eliminate the need for dowels, tie bars, joint forming, joint sealing, and texturing requirements. This assumes the brick has an asphalt overlay or is going to receive one. Full-depth repair of brick pavements built on a flexible base should be made with materials similar to existing. Generally this means Item 304 Aggregate Base and/or Item 301 Bituminous Aggregate Base. As many brick pavements occur inside municipalities, the agency responsible for maintenance should be contacted regarding their repair standards. This is particularly true for exposed brick pavements that will remain exposed. January

69 Pavement Design Procedures for Minor Rehabilitation Reflective Crack Control Reflective cracks refer to cracks in the asphalt over transverse or longitudinal joints or cracks in the concrete below. Reflective cracks are inevitable with composite pavements Sawing and Sealing Sawing and sealing, Item 413, consists of making a partial-depth saw cut in the asphalt overlay directly over existing transverse joints, immediately after paving. After the saw cuts are made, they are filled with a hot bituminous sealer. Sawing and sealing has proved very effective in controlling the location and deterioration of reflective cracks. Care must be taken to properly locate and align the saw cuts or the treatment will not be effective. Sawing and sealing is recommended anytime the concrete is exposed, either because it has never been overlayed or because the existing overlay has been removed Fabrics and Geogrids Paving fabrics and geogrids have not been found to be cost effective in reducing transverse reflective cracking. However, studies have shown that fabrics can delay and sometimes reduce reflective transverse cracking, but not to the extent that future maintenance decisions are less costly or come at a later time. Paving fabrics can be effective in reducing reflective cracks over longitudinal joints. Fabrics may be considered for longitudinal joints, particularly widening joints and joints at concrete/asphalt interfaces. A Minimum overlay thickness of 1-1/2" (~38 mm) should be placed above fabric installations Concrete Pavement Restoration Concrete Pavement Restoration (CPR) generally consists of some combination of full- and partialdepth repair, diamond grinding, joint resealing, crack sealing and undersealing. Experience has shown that adding tied concrete shoulders is not cost effective and is not recommended as part of a CPR. CPR is recommended as the first rehabilitation action for most existing concrete pavements. CPR maintains the concrete surface and avoids the reflective cracking that comes with composite pavements. CPR may not be the best choice for pavements built with slag aggregate as they tend to deteriorate on the surface first Geometric Issues Many times there are geometric problems with the roadway such as vertical clearance, curb reveal, cross-slope, etc., that need to be addressed. Some geometric problems can be easily corrected as part of the pavement rehabilitation. Crossslopes can be adjusted with either variable depth milling or a layer of asphalt with variable thickness or a combination of the two. Other problems are not fixed so easily. To meet at-grade bridges and provide clearance under overhead bridges, the overlay is often thinned down or the milling depth increased. The minimum overlay thickness on concrete must still be maintained. If the minimum overlay thickness cannot be maintained, pavement must be removed or bridges raised. These areas with thinner pavement structure may exhibit more extensive and severe distresses as they age and will require more maintenance than the surrounding pavement. In some cases where a thick structural overlay is required, thinning down is not recommended and the pavement should be replaced or bridges raised. Curb reveal is often a problem in urban areas. The structural needs of the pavement should not be compromised to save old curb. Where there is insufficient curb height for the required overlay, the curbs should be replaced. When only a functional overlay is needed, then it may be practical to increase the milling depth at the face of the curb to provide the full overlay thickness while still maintaining the curb height Pavement Widening When widening a pavement, the best practice is to design the widening for the traffic and soils conditions present. When traffic and soils information is not available, match the existing pavement type, materials and thicknesses. In all cases the existing pavement and the widening should meet at the same subgrade elevation. The base under the widening should slope away from the existing pavement and drainage should be provided for the widening. Drainage can be achieved with pipe underdrains or possibly aggregate drains. Pipe underdrains should be tied into the existing outlets. Pavement widening in this section refers to additional lanes or turn lanes, etc. Adding paved shoulders or widening shoulders does not fall January

70 Pavement Design Procedures for Minor Rehabilitation under this definition. Rebuilt or widened shoulders should generally use asphalt. Widening projects in excess of four lane-miles must follow the Pavement Design and Selection Process Rigid Pavement When widening existing rigid pavement with concrete, the new pavement should be the same type as the old (plain or reinforced) and should be tied to the existing concrete using a Type D Longitudinal Joint per BP-2.1. Prior to specifying a Type D joint, the existing concrete should be cored to determine soundness. Where coring discloses unsound pavement; pavement repair, pavement replacement, or the elimination of the Type D joint should be considered. Widening of concrete pavement without tying longitudinally may create separation and/or faulting depending on traffic. The most important consideration when widening and tying rigid pavement is that transverse joints in the widening must be of the same type, placed at the same location, and in the same alignment as the existing. Mismatched transverse joints will induce cracking. Longitudinal joints are best located at lane lines. The worst location for a longitudinal joint is in the wheel path. If necessary, remove part of the existing pavement to prevent locating a longitudinal joint in the wheel path. Rigid pavements which are to be overlayed as part of the widening project should be considered composite pavements and follow the widening guidelines given in Section When widening a rigid pavement with another pavement type, the widening should be designed for the conditions at hand. If necessary, the base under the widening should be thickened so that the subgrade elevations will match. If the widening is thicker than the existing, the subgrade should be sloped away from the existing and drainage provided Flexible Pavement When widening existing flexible pavement with asphalt, the best practice is to make a saw cut at the edge of a lane and remove the outside edge of the existing asphalt. This not only removes the uncompacted asphalt at the edges, but ensures there will not be a longitudinal construction joint in the wheel path. When matching thickness with the existing, the exact buildup and lift thicknesses should follow the guidelines given in Section 404. When widening a flexible pavement with another pavement type, the widening should be designed for the conditions at hand. If necessary, the base under the widening should be thickened so that the subgrade elevations will match. If the widening is thicker than the existing the subgrade should be sloped away from the existing and drainage provided Composite Pavement When widening existing composite pavement with composite pavement, not only should the subgrade elevations match but the surface of the concrete must match as well. Because it will be overlayed immediately, use Item 305 Concrete Base for the concrete regardless what type the existing concrete is. However, if the existing concrete is reinforced, add a note requiring the 305 also be reinforced. Transverse joints should be the same location, alignment and type as the existing. Mismatched transverse joints will induce cracking. Tie the 305 to the existing concrete using a Type D Longitudinal Joint per BP-2.5. Prior to specifying a Type D joint, the existing concrete should be cored to determine soundness. If the existing concrete is too deteriorated at the edge, the widening should not be tied but simply butted up against. The longitudinal joint between the old and new concrete is best located at a lane line. It is recommended that some of the existing pavement be removed rather than placing the longitudinal joint in a wheel path. When widening a composite pavement with another pavement type, the widening should be designed for the conditions at hand. If necessary, the base under the widening should be thickened so that the subgrade elevations will match. If the widening is thicker than the existing the subgrade should be sloped away from the existing and drainage provided. January

71 500 Pavement Design Procedures for Minor Rehabilitation List of Figures Figure Date Subject January 1999 UTOVER Design Inputs

72 UTOVER Design Inputs January 1999 Reference Section 503 Parameter Default Value Recommended Value Reliability - All none see Figure Standard Deviation of Traffic - All Poisson s Ratio - Concrete Poisson s Ratio - Asphalt Elastic Modulus - Concrete 5,000,000 5,000,000 Resilient Modulus - Asphalt 450, ,000 Initial PSI - All 4.5* 4.5 Terminal PSI - All Modulus of Rupture - Concrete Load Transfer Coefficient - Concrete 3.2 See below Drainage Coefficient - Concrete * Early versions of UTOVER list 4.2 as the default Initial PSI when analyzing Flexible pavements. Load Transfer Coefficient (J) Existing Pavement Edge Support** No Edge Support Jointed Doweled Jointed Undoweled Continuously Reinforced ** Edge support includes tied concrete shoulders, integral curb, widened lane, etc. Widened lane refers to concrete slabs built 14 feet (~4.2 m) wide or wider, but striped for a standard 12-foot (~3.6 m) lane, leaving 2 feet (~0.6 m) outside the traveled lane to provide edge support.

73 Table of Contents 600 Major Rehabilitation Design Introduction Subgrade Determination Unbonded Concrete Overlay Fractured Slab Techniques Crack & Seat Rubblize & Roll Whitetopping 6-3

74 600 Major Rehabilitation Design Introduction Major rehabilitations are performed when the pavement condition is such that minor rehabilitation is no longer feasible. The Pavement Design and Selection Process, Appendix A, requires major rehabilitation when the PCR falls below 55. Minor rehabilitation projects may be bumped up to major because of specific conditions on the project. For example, project level analysis may reveal excessive repair quantities which make minor rehabilitation a poor choice economically. Major rehabilitations are designed for twenty-year traffic projections using the ESAL99 procedure. All major rehabilitations require a life-cycle cost analysis using the procedures in Section 700. Major rehabilitations include the techniques given here, as well as complete removal of the existing pavement and replacement with either concrete or asphalt. The design of new concrete and asphalt is given in Sections 300 and Subgrade Determination To design all major rehabilitations, including complete replacement, it is necessary to know the strength of the subgrade under the existing pavement. Subgrade strength can be estimated from historical subsurface investigations or by using the w 5 sensor readings from the Dynaflect. The chart in Figure shows the relationship between the w 5 readings and CBR. The chart uses the average w 5 reading plus two standard deviations. This information is shown on the Dynaflect printout for each direction tested. Once a major rehabilitation strategy is selected, additional soils investigation may be necessary. For all projects selected for complete replacement or rubblize and roll, soil borings or a soils profile is highly recommended. Projects selected for unbonded concrete overlay do not require additional soils information except possibly in areas where the pavement is being replaced because of bridges, etc. Projects selected for crack and seat generally do not need additional soils information but if the designer suspects soft subgrade it should be investigated as it can cause problems. When additional soils information is received and reviewed, the pavement design should be checked for adequacy. If the actual subgrade conditions are different from what was estimated, the pavement design may have to be adjusted. Local areas of weak or wet subgrade should be considered unsuitable subgrade soil and treated per the recommendations in Section Unbonded Concrete Overlay An unbonded concrete overlay is a new concrete pavement placed on top of an old, deteriorated concrete pavement with a thin layer of asphalt in between to act as a bond-breaker. The thickness of an unbonded concrete overlay is derived from the required thickness for a new concrete pavement reduced by an amount based on the effective thickness of the existing concrete. The design of an unbonded concrete overlay begins with the design of a new rigid pavement according to the procedures in Section 300. Next an asphalt overlay is designed using the UTOVER computer program and the procedures given in Section 500. The equation for determining the thickness of an unbonded concrete overlay, developed by the U.S. Army Corps of Engineers, is given below: where: ( ) ( ) 2 2 T = T T UCO N E T UCO = Required thickness of the unbonded concrete overlay. T N = Required thickness for a new concrete pavement. T E = Effective thickness of the existing concrete. The effective thickness of the existing concrete comes from the UTOVER printout. The column labeled Deff (PCC) must be manually averaged to find the effective thickness of the existing concrete. Best practice dictates averaging all the readings for the entire project, both directions, rather than averaging each direction separately and using the smaller or larger number. The design period used in the UTOVER analysis does not need to be twenty years as the Deff (PCC) does not change with different traffic inputs. An example of an unbonded concrete overlay design is given in Figures and January

75 Major Rehabilitation Design To minimize the elevation increase of an unbonded concrete overlay, removal of any existing asphalt overlay is recommended. Deteriorated joints and cracks do not need to be repaired prior to the overlay. Where existing pavement must be removed to meet the elevation of at-grade bridges or as a means of providing clearance at overhead bridges, it should be replaced with new concrete pavement. The thickness required is that which was calculated for new pavement when designing the unbonded concrete overlay, T N. A base of at least 6 inches (~150 mm) of Item 304 should be placed under the concrete. Item 452 Plain Concrete Pavement is recommended for all unbonded concrete overlays and the replacement areas. Because of the dowels and the required concrete cover, the minimum thickness is 8 inches (~200 mm). 602 Fractured Slab Techniques Fractured Slab Techniques are for rehabilitation of existing rigid or composite pavements. They involve impacting the concrete to break it into smaller pieces. The intent being to retard or eliminate reflective cracking in the asphalt overlay. Fractured slab techniques involve placement of a thick asphalt overlay. The increased elevation due to the thick overlay requires full-depth replacement to meet at-grade bridges and possibly to provide clearance at overhead bridges. The pavement in these replacement areas should be designed as full-depth flexible pavement on an aggregate base. The design of fractured slab techniques begins with the design of a new flexible pavement as described in Section 400. The structural number required for the new flexible pavement is the basis for all the fractured slab designs. Because these techniques turn a rigid pavement into a flexible pavement, subgrade conditions take on increased importance. Weak or wet subgrade can hamper the fracturing operation and may make the seating or rolling operation impossible. Ohio has a very famous photograph of a 50 ton roller buried up to its axles in the pavement because of too soft subgrade. Prior to designing a fractured slab technique, the w 5 sensor readings from the Dynaflect should be carefully reviewed to try and determine local areas of soft subgrade that may require undercutting and replacement. Prior to constructing a fractured slab technique, soil borings should be taken and specific replacement and undercut quantities should be set up in the plans. A third fractured slab technique, break and seat, was used extensively in Ohio in the past. While some sections had good performance, others performed very poorly. Break and seat is not to be used as a major rehabilitation strategy per the Pavement Design and Selection Process, Appendix A Crack & Seat Crack and seat is for use on plain concrete pavements only. It is not for use on reinforced pavements whether jointed or continuous. The cracks induced are very light and are visible only with the application of water. Prior to cracking, any existing asphalt overlay must be removed. To design a crack and seat, the thickness of the cracked concrete is multiplied by a structural coefficient, given in Figure Asphalt layers are then added until the total structural number is equal to or greater than the structural number required for a new flexible pavement. Any existing subbase under the concrete is neglected. An example is shown in Figure Rubblize & Roll Rubblize and roll can be used on all concrete pavements although it is primarily intended for reinforced concrete. The rubblizing process does just what the name implies, it reduces the concrete to rubble. All slab action is destroyed and the concrete is transformed into an aggregate base. Prior to rubblizing, any existing asphalt overlay must be removed. Subgrade support is even more important for rubblize and roll than for crack and seat. Soil borings are strongly encouraged as early as possible in the design phase. Where subgrade conditions are very poor, analysis of the soil borings may reveal such large areas requiring replacement and undercutting that the decision to rubblize should be reconsidered. As a rule of thumb, areas three percent or more above January

76 Major Rehabilitation Design optimum water content will require undercutting and replacement. Another rule of thumb was developed to estimate optimum water content: the optimum water content is the Plastic Limit minus four. Plastic Limit is not to be confused with the Plasticity Index. The Plastic Limit is equal to the Liquid Limit minus the Plasticity Index. To design a rubblize and roll, the thickness of the rubblized concrete is multiplied by a structural coefficient, given in Figure Asphalt layers are then added until the total structural number is equal to or greater than the structural number required for a new flexible pavement. Any existing subbase under the concrete is neglected. An example is shown in Figure Whitetopping Whitetopping is the construction of a new rigid pavement on top of an existing asphalt pavement. It is not to be confused with ultra-thin whitetopping which is a thin layer of concrete placed on top of asphalt to prevent rutting and shoving. Whitetopping is designed as a new rigid pavement using the existing asphalt pavement as the base for determining the modulus of subgrade reaction. January

77 600 Major Rehabilitation Design List of Figures Figure Date Subject January 1999 Unbonded Concrete Overlay Example January 1999 UTOVER Output (Modified) January 1999 Fractured Slab Examples

78 Unbonded Concrete Overlay Example January 1999 Reference Section 601 Given: Rigid Pavement Design Example, Figure Existing pavement buildup: 3" Asphalt 9" Reinforced Concrete 6" Subbase UTOVER output, Figure Problem: Design an unbonded concrete overlay. Solution: Obtain required thickness for new rigid pavement. T N = 9.6" (from Figure 302-1) Obtain effective thickness of existing concrete. T E = 8.69" (from Figure 601-2) Calculate required thickness of unbonded concrete overlay. T T T T UCO UCO UCO UCO ( 96. ) ( 87. ) = 2 2 = = = 406. " Items of work: Minimum thickness of unbonded concrete overlay = 8" 452 8" Plain Concrete Pavement 448 Asphalt Concrete Intermediate Course, Type 1, PG (1" thick) 202 Wearing Course Removed

79 UTOVER Output (Modified) January 1999 Reference Section 601 TITLE: MIL Lane 4 12-yr 4/29/98 PROJECT: DISTRICT: 15 COUNTY: MILLER ROUTE: 001 PAVE. TYPE: COMPOSITE LANE TESTED/NO. OF LANES: 4/4 TEST DATE: 4/ 1/97 WEATHER: CLOUDY PAVE. TEMP.: 31F EXISTING PAVEMENT TYPE: COMPOSITE OVERLAY PAVEMENT TYPE: AC OVERLAY GEOMETRY OF EXISTING PAVEMENT: OVERLAY DESIGN: THICKNESS OF AC LAYER = 3.00 DESIGN TRAFFIC, E18 = POISSON RATIO AC =.350 RELIABILITY, R = 90.0% ELAS. MODULUS OF NEW AC = ZR = THICKNESS OF PCC SLAB = 9.00 TRAFFIC STANDARD DEVIATION, S0 =.10 POISSON RATIO OF PCC =.150 INITIAL PSI Pi = 4.50 ELAS. MODULUS OF NEW PCC= TERMINAL PSI Pt = 2.50 ELASTIC MODULUS OF NEW PCC Ec = TOTAL DEPTH OF PAVEMENT = NEW PCC MODULUS OF RUPTURE Sc = EQUIVALENT POISSON RATIO=.200 LOAD TRANFER COEFFICIENT J = 3.20 EQUIVALENT ELAS. MODULUS= DRAINAGE FACTOR Cd = 1.00 LOCA. W1 W2 W3 W4 W5 Lk Ep k Deff Dreq Hover (PCC) (PCC) (AC) (mils) (in.) (ksi) (pci) (in.) STATISTICAL RESULTS SUMMARY: NUMBER OF DATA POINTS = 46 Avg. Deff = 8.69" AVG A(Dreq - Deff) = STD A(Dreq - Deff) = DESIGN AC OVERLAY THICKNESS AT 90.00% RELIABILITY LEVEL = 3.92

80 Fractured Slab Examples January 1999 Reference Section 602 Crack & Seat Example Given: Flexible Pavement Design Example, Figure Existing pavement buildup: 3" Asphalt 8" Item 305 Concrete Base 6" Subbase Problem: Design a Crack & Seat project. Solution: Obtain required structural number for a new flexible pavement SN = 4.5 (from Figure 402-1) Determine the required buildup using the structural coefficients given in Figure Material Thickness Coefficient SN 446 Surface 1.5" x 0.35 = Intermediate 1.75" x 0.35 = " x 0.35 = (cracked & seated) 8" x 0.27 = 2.16 Total Structural Number = 4.69 Rubblize & Roll Example Given: Flexible Pavement Design Example, Figure Existing Pavement Buildup: 4" Asphalt 9" Reinforced Concrete 6" Subbase Problem: Design a Rubblize & Roll project. Solution: Obtain required structural number for a new flexible pavement. SN = 4.5 (from Figure 402-1) Determine the required buildup using the structural coefficients given in Figure Material Thickness Coefficient SN 446 Surface 1.5" x 0.35 = Intermediate 2" x 0.35 = " x 0.35 = 2.10 Rubblized Concrete 9" x 0.14 = 1.26 Total Structural Number = 4.58

81 Table of Contents 700 Life-Cycle Cost Analysis Introduction Alternatives Considered Analysis Period Estimated Prices Discount Rate Initial Construction Future Maintenance Introduction Maintenance Schedules Flexible Pavement Rigid Pavement Composite Pavement Unbonded Concrete Overlay Fractured Slab Techniques Whitetopping Total Cost Discounting Lane Closure Days Results Presentation 7-4

82 700 Life-Cycle Cost Analysis Introduction Life-Cycle Cost Analysis (LCCA) is a process for evaluating the economic worth of a pavement segment by analyzing initial costs and discounted future costs such as preventive maintenance, resurfacing, rehabilitation, and reconstruction costs over a defined analysis period. Personal and District preferences must be set aside to attempt to come up with a fair, unbiased LCCA. It is important to be fair to all alternatives in terms of price and performance. The LCCA is only a tool in the decision-making process, it does not dictate a decision. The results of the LCCA are not decisions but are important information used in reaching decisions Alternatives Considered All reasonable alternatives are to be included in the LCCA. This includes rigid pavement, new or complete replacement; flexible pavement, new or complete replacement; unbonded concrete overlay; crack and seat; rubblize and roll; and whitetopping. Expected cost is not a good reason to exclude an alternative from the analysis. For example, complete replacement is generally the most expensive alternative but it should not be disregarded simply because of the expectation of high cost. The analysis may show replacement as the highest cost but the cost differential between replacement and the other alternatives may be small enough to make replacement the better choice. Sometimes it is necessary to eliminate alternatives because of the overlay thickness and problems with bridges. Particularly on urban projects where there may be a high number of at-grade and overhead bridges, alternatives which require a thick overlay and therefore a significant increase in elevation may not be good choices. Some preliminary investigation should be done to determine the amount of pavement removal and undercutting necessary to meet at-grade bridges and provide clearance under overhead bridges. If the amount of removal necessary for an alternative exceeds about 40% of the pavement, assuming none of the bridges are jacked, then it may not be necessary to consider that alternative Analysis Period The LCCA analysis period for new pavements and major rehabilitations is 35 years. Because the analysis period exceeds the structural design life, future maintenance and rehabilitation actions must be predicted and included in the analysis to keep the pavement in serviceable condition for the 35- year period Estimated Prices Prices should be estimated based on recent projects; similar quantities; and, where possible, geographic proximity. All prices, for both initial construction and future maintenance, are to be estimated using current bid prices. No escalation is to be given for inflation. The analysis is performed using constant (or real) dollar values and real discount rates instead of using inflated (or nominal) dollar values and nominal discount rates. Prices should be relative for all projects. If low prices are selected for one alternative, then low prices must be used for all alternatives. Prices should not be manipulated to achieve the desired outcome. No unusually high or low prices should be used without solid justification. The use of statewide average prices is discouraged. The state averages, while weighted, tend to be too high due to all the small quantity jobs. Most LCCA s involve large quantities and the prices come in much lower than the statewide averages Discount Rate Rather than choose one explicit discount rate, ODOT uses a range of rates to see how the discount rate affects the outcome. Total life-cycle cost is calculated for discount rates of 0, 1, 2, 3, 4, 5, and 6 percent. Results are then displayed in tabular and graphical form to see how the discount rate affects the apparent least-cost alternative. 701 Initial Construction All alternatives for initial construction are designed using the procedures outlined in this Manual and in accordance with Appendix A, Pavement Design & Selection Process. Initial construction is considered to take place in year zero. All pavement items are to be included in the analysis such as excavation, subgrade compaction, pavement removed, base, free draining base, and pavement. Non-pavement items and items common to all alternatives can be neglected. Items such as striping, signing, lighting, guardrail, barrier, underdrains, culverts, bridges, embankment, etc., are not pavement items, are essentially equal for all alternatives and are not to January

83 Life-Cycle Cost Analysis be included in the analysis. On new locations, earthwork items including subgrade compaction are common to all pavement alternatives and are essentially equal and therefore do not need to be included. For rehabilitations that raise the elevation of the existing pavement, a cost needs to be included for maintaining clearance under overhead structures and for meeting elevations of at-grade bridges. For convenience, this is known as the cost of maintaining clearance. This cost can be calculated in various ways. One way is to calculate the cost to remove the existing pavement, excavate down, and build back up with new pavement. Another way is to calculate the cost of jacking the bridges, including any approach work necessary on overheads. A third option could be a combination of the two. It is not important which method is selected for computing cost of maintaining clearance. What is important is that a dollar amount is included in the analysis to account for the cost of maintaining clearance. For convenience, it is recommended to use the same method for all alternatives, i.e. do not remove pavement and excavate for the rubblize alternative and then jack bridges for the unbonded concrete overlay alternative. The method used in the LCCA for computing cost of maintaining clearance does not have to be the actual method used in the plans and in construction. 702 Future Maintenance Introduction The future maintenance required to keep the pavement in serviceable condition for the next 35 years must be predicted. The number one factor when determining required maintenance is engineering judgement. The performance equations given in Figure are useful guidance. It is important to note the performance being predicted is for pavements built to current specifications, not 1960's specifications. Many changes and improvements have been made to both asphalt and concrete including such things as PG binders, polymers, gradation changes, free draining bases, epoxy coated steel, non d-cracking aggregates, etc. These changes are expected to result in improved performance and this improved performance should be reflected in the LCCA. Routine maintenance performed by ODOT forces has traditionally been ignored due to lack of dependable data. Only contract maintenance is considered. ODOT does not use salvage value. This means when choosing the maintenance strategies and timing, the designer must try to balance them such that all alternatives are in approximately the same condition in year 35. Generally the goal is to have each alternative require additional maintenance just after the end of the analysis period. In other words, do not place a thick overlay on one alternative in year 32 while doing nothing since year 25 on the other alternatives Maintenance Schedules The maintenance strategies and schedules given below are for informational purposes only. This information is intended to give designers some reasonable guidance when deciding the maintenance actions for an LCCA. Wide latitude is given on both the timing and the work predicted. The designer is not restricted to these schedules; but, because of the wide latitude given, anything outside the schedules may be questioned. All thicknesses given are approximate but overlays much thicker or much thinner than those listed are not expected. The schedules list only major items of work. The designer may need to include additional items. For instance, tack coats are not listed but are required with all overlays. It is not intended that every item listed be used in a given year. For example, concrete pavement shows both an asphalt overlay and diamond grinding as options but never would the two of them be done at the same time. It is further not intended that actions must take place in every one of the years listed. Depending on the expected performance and the actions predicted for the early years, the later rehabilitation(s) may not be necessary Flexible Pavement Flexible pavement includes new pavement on a new alignment and complete replacement of existing pavement. Year 10-15: Thin overlay, 1.25" - 3" (~32-75 mm), with or without milling. January

84 Life-Cycle Cost Analysis Year 18-25: Thick overlay, 3" - 7" (~ mm), with milling, possibly pavement repairs. Year 28-32: Thin overlay or micro-surfacing or crack sealing. Many times the third treatment would not be necessary at all depending on the timing of the first two and the thickness of the overlays and their expected performance Rigid Pavement Rigid pavement includes new pavement on a new alignment and complete replacement of existing pavement. Percentages given are of the total mainline pavement area not including shoulders or ramps or turn lanes, etc. Year 18-25: 2% - 10% full-depth rigid repairs, 1% - 5% partialdepth bonded repairs, diamond grinding, 3" - 6" (~ mm) overlay, sawing and sealing. Year 28-32: 1% - 3% full- and/or partial-depth repairs, 1.25" - 2" (~32-50 mm) second overlay with or without milling, 3" - 4" (~ mm) first overlay, sawing and sealing, micro-surfacing, crack sealing, diamond grinding. Best practice dictates the use of diamond grinding for the first treatment. Placing an asphalt overlay on a concrete pavement brings on a new set of problems and is discouraged as the first predicted maintenance action. Remember, this is the predicted performance of pavements built to current specifications, not 1960's specifications. Again, in many cases the second treatment may not be necessary at all Composite Pavement Composite pavement is a hybrid of rigid and flexible pavement and requires the maintenance actions of both. It is generally expected to receive full-depth rigid repairs, milling and an overlay every 8-12 years Unbonded Concrete Overlay An unbonded concrete overlay is in essence a new concrete pavement built on top of the old. It will require maintenance similar to that for a rigid pavement. It may be reasonable to expect slightly less repair for an unbonded concrete overlay versus new rigid pavement due to the much thicker pavement section Fractured Slab Techniques Fractured slab techniques include crack & seat, and rubblize & roll. Year 8-12: Thin overlay, 1.25" - 4" (~ mm) with or without milling. Year 16-22: Thick overlay, 4" - 8" (~ mm) with milling, pavement repair. Year 24-32: Thin overlay, 1.25" - 4" (~ mm) with or without milling, micro-surfacing, crack sealing. Fractured slab techniques are more likely to require the third maintenance action than is flexible pavement Whitetopping Whitetopping is in essence a new concrete pavement built over an existing flexible pavement. It is expected to perform similar to a rigid pavement or an unbonded concrete overlay. June

85 Life-Cycle Cost Analysis 703 Total Cost Once all the costs for initial construction and future maintenance have been calculated, they are summed to determine the net present value of each alternative. Future maintenance costs are discounted which accounts for and the time value of money Discounting Discounting is a simple yet effective way to account for the time value of money. The discount rate is essentially the difference between market interest rates and the general rate of inflation. For example, one-year Certificates of Deposit (CD) might be paying 5.5% while inflation is running 2.0% per year, the discount rate would be 3.5%. By the same token, if CD s are paying 8.0% and inflation is running 4.5%, the discount rate is still 3.5%. Using a discount rate thus eliminates the need to predict what inflation will do for the next 35 years or what return one might get on an investment. The formula for applying the discount rate is as follows: (P/F,i%,n) = 1 ( 1+ i) n where: (P/F,i%,n) = discount factor i = discount rate (0% to 6%) n = year costs occur An example showing how to use the discount rate and calculate total cost is given in Figure Lane Closure Days Lane closure days is a measure of the impact of each alternative on the traveling public. It is not a measure of the time needed to construct each alternative. It is merely a comparison tool given a standard work crew, a ten-hour day, a single-lane closure, etc., of how many days it would take to complete each alternative. One lane closure day equals twenty-four hours that a lane is not available to traffic even though work is only being performed for ten hours. The production rates for certain items which can be opened to traffic upon completion of each day s work have been adjusted to account for the fact the lane is not closed twenty-four hours. The production rates used in calculating the number of days of lane closure are given in Figure Results Presentation A great deal of information is contained in the LCCA and the supporting documentation. It is important it be presented in a standard format. Examples are given in Figures and The first page of the report gives general information about the project and the alternatives and provides space for the members of the Pavement Selection Committee to sign off on one alternative. The second page summarizes the District s selected alternative. This page lists each of the principal and secondary factors from the Pavement Design and Selection Process, Appendix A, and gives justification for the selected alternative for each factor. Additional pages may or may not be necessary to give more detailed information on the initial buildups, predicted future maintenance, widening buildups, etc. One page gives background information on the project including historical data on the project, the original construction project, all rehabilitations to date, the existing buildup, etc.; also, the physical attributes such as interchanges, intersections, overhead and at-grade bridges, etc.; and the condition of the existing pavement, PCR, traffic, functional classification, etc. Next are pages showing the details of the LCCA such as items, quantities, prices and costs for initial and future construction. Next, a graph showing how the discount rate affects the apparent least cost alternative and finally a page giving the lane closure analysis. Once all the information is assembled, the District Deputy Director should sign off on one alternative. The package is then sent to the Pavement Design Section of the Office of Materials Management who will review the LCCA package for concurrence and then forward the report to the Pavement Selection Committee for approval. The Committee will return the signed copy to the Pavement Design Section who will inform the District of the decision and notify FHWA, if necessary. June

86 700 Life-Cycle Cost Analysis List of Figures Figure Date Subject January 1999 Discounting Example January 1999 Lane Closure Days January 1999 Rehabilitation Example Page June 1999 Rehabilitation Example Page 1a January 1999 Rehabilitation Example Pages June 1999 New Pavement Example Pages 1-5

87 Discounting Example January 1999 Reference Section Given: Initial Construction (Year 0): $6,500,000 First Maintenance (Year 12): $800,000 Second Maintenance (Year 20): $1,600,000 Third Maintenance (Year 30): $200,000 Problem: Solve for the net present value using discount rates of 0, 1, 2, 3, 4, 5, and 6%. Solution: Calculate the discount factor for each year and discount rate using the equation given in Section Rate Year 0 Year 12 Year 20 Year 30 0% % % % % % % Multiply costs by discount factors and sum to find Net Present Value (NPV) at each discount rate. NPV 0% = ( )*(1)+(800000)*(1)+( )*(1)+(200000)*(1) = $9,100,000 NPV 1% = ( )*(1)+(800000)*(0.8874)+( )*(0.8195)+(200000)*(0.7419) = $8,669,500 NPV 2% = ( )*(1)+(800000)*(0.7885)+( )*(0.6730)+(200000)*(0.5521) = $8,318,020 NPV 3% = ( )*(1)+(800000)*(0.7014)+( )*(0.5537)+(200000)*(0.4120) = $8,029,440 NPV 4% = ( )*(1)+(800000)*(0.6246)+( )*(0.4564)+(200000)*(0.3083) = $7,791,580 NPV 5% = ( )*(1)+(800000)*(0.5568)+( )*(0.3769)+(200000)*(0.2314) = $7,594,760 NPV 6% = ( )*(1)+(800000)*(0.4970)+( )*(0.3118)+(200000)*(0.1741) = $7,431,300

88 Lane Closure Days January 1999 Reference Section 704 Item # Description ENGLISH METRIC Prod. Rate Prod. Rate Wearing Course Removed 11,250 SY/Day 9406 m 2 /Day 202 Pavement Removed SY/Day m 2 /Day 202 Base Removed 1000 CY/Day 765 m 3 /Day 203 Excavation not Inc. Embankment 2500 CY/Day 1911 m 3 /Day 203 Subgrade Compaction 1 Day/Lane 1 Day/Lane 203 Proof Rolling 48,750 SY/Day 40,761 m 2 /Day 206 Lime Soil Stabilized Subgrade 2125 SY/Day 1776 m 2 /Day 252 Partial Depth Pavement Repair 1625 SY/Day 1359 m 2 /Day 252 Rigid Remove/Flexible Replace 1000 SY/Day 836 m 2 /Day 252 Pavement Sawing 1 Day/Lane 1 Day/Lane 253 Pavement Repair 875 CY/Day 669 m 3 /Day 254 Pavement Planing - Bituminous 2, SY/Day 2, m 2 /Day 254 Pavement Planing - PCC SY/Day m 2 /Day 255 Rigid Remove/Rigid Repl. Class C SY/Day m 2 /Day 255 Pavement Sawing 1 Day/Lane 1 Day/Lane 301 Bituminous Aggregate Base (302) 875 CY/Day 669 m 3 /Day 304 Aggregate Base 1250 CY/Day 956 m 3 /Day 305 Concrete Base SY/Day m 2 /Day 306 Cement Treated FDB SY/Day m 2 /Day 307 Non Stabilized Drainage Base SY/Day m 2 /Day 407 Tack Coat Neglect Neglect 408 Bituminous Prime Coat Neglect Neglect 409 Seal Coat Neglect Neglect 413 Sawing and Sealing 1875 LF/Day 571 m/day AC Surface Course, Type 1 4, CY/Day 4,7 860 m 3 /Day AC Intermediate Course, Type CY/Day m 3 /Day AC Surface Course, Type 1 4, CY/Day 4,7 956 m 3 /Day AC Intermediate Course, Type CY/Day m 3 /Day 451 & 452 Concrete Pavement (MAINLINE) SY/Day m 2 /Day 451 & 452 Concrete Pavement (SHOULDERS) SY/Day m 2 /Day 453 CRC Pavement SY/Day m 2 /Day Special Asphalt Treated FDB SY/Day m 2 /Day Special Cracking and Seating 12,500 SY/Day 10,451 m 2 /Day Special Rubblize and Roll 2500 SY/Day 2090 m 2 /Day Joint Clean/Seal - All Types 4 13,750 LF/Day + 1 Day/ Lane m/day + 1 Day/Lane

89 Notes to Lane Closure Days Figure For situations where shoulders are being removed for replacement, pavement removal and wearing course removal can be done simultaneously. Only use the greater of the two quantities depending on the project 2. On future maintenance only, where planing and a one-course overlay are being performed as one continuous operation, such as thin mill and fill jobs often done as night work, the production rate for this item should be doubled and the time for the overlay neglected. 3. On future maintenance only, where conditions allow the pavement to be opened to traffic at the end of each ten hour work day, the production rate for this item should be doubled. When the dropoff between lanes is too large and the pavement cannot be opened to traffic until the item is completed or other work is being performed which prevents the pavement from being opened, the given production rate should be used with no doubling. 4. Production rates for these items have been adjusted to reflect the fact that the pavement is opened to traffic during the part of the day when work is not being performed. 5. All concrete pavement items do not include the curing time. The curing time should be added to the summary where applicable in the final analysis. Class C - 10 Days/Project Class MS - 2 Days/Project Class FS - 1 Day/Project 6. Where type is yet to be determined, use 3125 SY/Day (2612 m 2 /Day). 7. Where Sawing and Sealing is specified, use only 1 Day/Lane for or

90 Rehabilitation Example Page January 1999 Reference Section 705 Pavement Type and Rehabilitation Strategy Approval Project: ABC Date: February 29, 1999 Length: 7.84 miles PID No.: Plans: 20 % complete Program Amount: $25,000,000 Alternative 1: Rubblize and Roll - Remove the existing asphalt overlay, rubblize the existing concrete and overlay with 13.5" of asphalt. Twenty-nine percent removal, undercut and replacement is required to meet at-grade bridges and provide clearance at overhead bridges, assuming bridges are not jacked. Alternative 2: Unbonded Concrete Overlay - Remove the existing asphalt overlay, place a 1" asphalt bondbreaker layer and overlay with 8" of plain concrete. Twenty-two percent removal, undercut and replacement is required to meet at-grade bridges and provide clearance at overhead bridges, assuming bridges are not jacked. Alternative 3: Flexible Replacement - Remove the existing pavement and replace with 12.75" of asphalt on 12" of 304. Alternative 4: Rigid Replacement - Remove the existing pavement and replace with 12" of reinforced concrete on a Free Draining Base on 6" of 304. PLEASE INDICATE BELOW YOUR APPROVAL OF ONE OF THE ALTERNATIVES THEN RETURN TO MATERIALS MANAGEMENT Pavement Selection Committee District Deputy Director Assistant Director for Transportation Policy Assistant Director for Field Operations Deputy Director of Engineering Policy New Design/ Rehabilitation Approval Alt. 1 Alt. 2 Alt. 3 Alt. 4

91 Rehabilitation Example Page 1a June 1999 Reference Section 705 Selection Summary Sheet Alternative 2, Unbonded Concrete Overlay, has been selected by the District. The following discussion concerning this selection is provided in an effort to communicate the rational for this decision. Principal Factors LCCA: The Unbonded Concrete Overlay has the lowest life-cycle cost for discount rates between zero and three percent. Above approximately 3.5%, Alternative 3, Flexible Replacement, has the lowest lifecycle cost, however, even at a 6% discount rate, the Unbonded Concrete Overlay is less than 5% more than the Flexible replacement. Differences of five to ten percent between alternatives are considered insignificant for most life-cycle cost analyses. Initial Cost: The Flexible Replacement has the lowest initial cost and none of the other alternatives are within five percent. The Unbonded Concrete Overlay is more than ten percent greater than the Flexible, however, given its other advantages, District felt the additional initial cost was justified. User Delay: The Unbonded Concrete Overlay has the fewest days of lane closure. Municipal Preference: This project is rural and is not located within any municipality. Secondary Factors Geometrics: This project, classified as hilly terrain, includes three locations where grade is in excess of 3%. The District has had problems in the past with rutting where 1% to 2% grades are present for bridge embankments. Based on our desire to reduce maintenance required on the pavement, the Unbonded Concrete Overlay is preferred. The life-cycle cost analysis did not account for any additional costs which might be associated with the use of special rut-resistant asphalt mixes. Constructability: Due to the widening, all of the alternatives could be constructed without crossing traffic over, however, part-width construction is not recommended with free draining bases. Since there are no interchanges on this project, traffic could easily be crossed over to allow the contractor full access to one side. We see no major advantages or disadvantages regarding constructability/maintenance of traffic for any of the alternatives. Availability of Local Materials: Our District finds it difficult to find quality aggregates for both asphalt and concrete. We see no real advantage for any alternative. Other Issues: Our District has had very good performance with unbonded concrete overlays in the past.

92 Rehabilitation Example Page January 1999 Reference Section 705 Initial Construction Designs Alternative 1: Rubblize and Roll 1.5" 446 Asphalt Concrete Surface Course, Type 1H 407 Tack Coat for Intermediate Course 1.75" 446 Asphalt Concrete Intermediate Course, Type " 302 Bituminous Aggregate Base Special Rubblize and Roll Existing Reinforced Concrete Pavement Alternative 2: Unbonded Concrete Overlay 8" 452 Plain Concrete Pavement 1" 448 Asphalt Concrete Intermediate Course, Type 1 Alternative 3: Flexible Replacement 1.5" 446 Asphalt Concrete Surface Course, Type 1H 407 Tack Coat for Intermediate Course 1.75" 446 Asphalt Concrete Intermediate Course, Type 2 9.5" 302 Bituminous Aggregate Base 12" 304 Aggregate Base Alternative 4: Rigid Replacement 12" 451 Reinforced Concrete Pavement Special Free Draining Base 408 Bituminous Prime Coat 6" 304 Aggregate Base

93 Rehabilitation Example Page January 1999 Reference Section 705 Widening Buildups Alternative 1: Rubblize and Roll 1.5" 446 Asphalt Concrete Surface Course, Type 1H 407 Tack Coat for Intermediate Course 1.75" 446 Asphalt Concrete Intermediate Course, Type " 302 Bituminous Aggregate Base 12" 304 Aggregate Base Alternative 2: Unbonded Concrete Overlay 12" 452 Plain Concrete Pavement 13" 304 Aggregate Base

94 Rehabilitation Example Page January 1999 Reference Section 705 Anticipated Future Maintenance Alternative 1: Rubblize and years: 1.5" mill and fill 4" overlay with milling 1.5" mill and fill Alternative 2: Unbonded Concrete 25 years Repair 5% of the pavement, grind for smoothness and reseal joints Alternative 3: Flexible years: 2" mill and fill 4" overlay with milling Alternative 4: Rigid 25 years: Repair 5% of the pavement, grind for smoothness and reseal joints

95 Rehabilitation Example Page January 1999 Reference Section 705 Project Summary Historical Data Project Numbers 530(57) 557(57) SLM 8.30 Project Length Pavement Buildup 7.84 miles 5.25" Asphalt 10" Reinforced Concrete 6" Subbase Joint Spacing 60' Drainage Pipe Underdrains Rehabilitations to date 571(72) 159(86) Physical Attributes Signalized Intersections Interchanges Overhead Structures Structure None None Five Clearance '-3" ) 15'-1" '-11" ) 15'-3" '-8" ) 15'-0" '-0" ) 15'-7" '-1" ) 14'-10" At-Grade Structures Three Sets Project Evaluation Overall Condition Fair to Poor PCR/Structural Deduct 59/21 20-year Design ESAL s 65.5 million (Rigid) 47.4 million (Flexible) ADT (1994) % Trucks (1994) 34% Functional Classification Rural Interstate

96 Rehabilitation Example Page January 1999 Reference Section 705 Initial Construction Quantities ITEM DESCRIPTION UNIT AMT. Alt. 1 Alt. 2 Alt. 3 Alt Pavement Removed SY 62,400 49, Pavement Removed SY 218, , Wearing Course Rem. SY 220, , Excavation CY 237, , , , Subgrade Compaction SY 324, , Subgrade Compaction SY 545, , Bit. Aggregate Base CY , Bit. Aggregate Base CY , Bit. Aggregate Base CY , Aggregate Base CY 6 90, Aggregate Base CY , Aggregate Base CY , Aggregate Base CY , Tack Coat Gal 40,930 40, Bituminous Prime Coat Gal 218, AC Surface, Type 1 CY ,739 22, AC Intermediate, Type 2 CY ,529 26, AC Intermediate, Type 1 CY 1 15, Plain Concrete Pavem't SY 8 239, Plain Concrete Pavem't SY , ,733 Special Rubblize and Roll SY 155,893 Special Free Draining Base SY 545,733

97 Rehabilitation Example Page January 1999 Reference Section 705 Future Maintenance Quantities ITEM DESCRIPTION UNIT AMT. Alt. 1 Alt. 2 Alt. 3 Alt. 12 Years 254 Pavement Planing SY 545, Patching Planed Surface SY 3% 16, Tack Coat Gal 40, AC Surface, Type 1 CY Years 254 Pavement Planing SY 545, Patching Planed Surface SY 3% 16, Tack Coat Gal 40, AC Surface, Type 1 CY 2 20 Years 254 Pavement Planing SY 545, Patching Planed Surface SY 3% 16, Tack Coat Gal 81, AC Surface, Type 1 CY , AC Intermediate, Type 2 CY Years 254 Pavement Planing SY 545, Patching Planed Surface SY 3% 16, Rigid Repairs SY 5% 16,372 16, Pavement Sawing LF 5% 73,674 73, Tack Coat Gal 81, AC Surface, Type 1 CY , AC Intermediate, Type 2 CY , Longit. Joint Sealing LF 327, , Trans. Joint Sealing LF 313, ,476 Special Diamond Grinding SY 327, Years 254 Pavement Planing SY 545, Patching Planed Surface SY 3% 16, Tack Coat Gal 40, AC Surface, Type 1 CY ,739

98 Rehabilitation Example Page January 1999 Reference Section 705 Initial Construction Costs Price ITEM DESCRIPTION Alt. 1 Alt. 2 Alt. 3 Alt Pavement Removed $4.74 $295,776 $232, Pavement Removed $4.00 $873,173 $873, Wearing Course Rem. $0.75 $165,637 $179, Excavation $2.11 $501,480 $402,397 $455,268 $413, Subgrade Compaction $0.55 $178,686 $168, Subgrade Compaction $0.50 $272,867 $272, Bit. Aggregate Base $32.41 $4,667, Bit. Aggregate Base $32.12 $2,918, Bit. Aggregate Base $32.12 $4,240, Aggregate Base $20.00 $1,819, Aggregate Base $20.00 $2,243, Aggregate Base $18.00 $3,274, Aggregate Base $20.00 $2,250, Tack Coat $0.77 $31,516 $31, Bituminous Prime Coat $0.70 $152, AC Surface, Type 1 $60.00 $1,364,333 $1,364, AC Intermediate, Type 2 $42.49 $1,127,205 $1,127, AC Intermediate, Type 1 $37.00 $560, Plain Concrete Pavement $18.00 $4,315, Plain Concrete Pavement $20.00 $6,119,911 $10,914,667 Special Rubblize and Roll $1.77 $275,931 Special Free Draining Base $2.35 $1,282,473 Total Initial Construction $13,048,034 $13,996,777 $12,066,222 $15,728,783

99 Rehabilitation Example Page January 1999 Reference Section 705 Future Maintenance Price Costs ITEM DESCRIPTION Alt. 1 Alt. 2 Alt. 3 Alt. 12 Years 254 Pavement Planing $0.55 $300, Patching Planed Surface $0.40 $6, Tack Coat $0.77 $31, AC Surface, Type 1 $ Years 254 Pavement Planing $0.55 $300, Patching Planed Surface $0.40 $6, Tack Coat $0.77 $31, AC Surface, Type 1 $ Years 254 Pavement Planing $0.55 $300, Patching Planed Surface $0.40 $6, Tack Coat $0.77 $35, AC Surface, Type 1 $60.00 $1,364, AC Intermediate, Type 2 $ Years 254 Pavement Planing $0.55 $300, Patching Planed Surface $0.40 $6, Rigid Repairs $45.00 $736,740 $736, Pavement Sawing $1.42 $104,617 $104, Tack Coat $0.43 $35, AC Surface, Type 1 $60.00 $1,364, AC Intermediate, Type 2 $39.67 $1,503, Longit. Joint Sealing $1.00 $327,440 $327, Trans. Joint Sealing $1.25 $391,845 $391,845 Special Diamond Grinding $2.00 $654, Years 254 Pavement Planing $0.55 $300, Patching Planed Surface $0.40 $6, Tack Coat $0.77 $31, AC Surface, Type 1 $60.00 $1,364,333 Total Future Maintenance $6,614,758 $2,215,522 $5,799,023 $2,215,522 Total Cost of Alternative $19,662,792 $16,212,299 $17,865,245 $17,944,304

100 Rehabilitation Example Page January 1999 Reference Section 705 Sensitivity Analysis of the Discount Rate The Discount Rate is a tool used in evaluating the time value of money. It is broadly defined as the difference between market interest rates and inflation. Because costs are incurred at different points in time over the life of a pavement, the discount rate is used to compare these costs in terms of constant dollars. In this case, 1998 dollars have been used as constant dollars. A survey of states done in the mid 1990's indicated the range of discount rates used throughout the country varies from 0% to 7%. The most common rate used was 4%. Rather than using just one discount rate, a range of rates has been used to show how different rates affect the apparent least cost alternative. Rate Alt. 1 Alt. 2 Alt. 3 Alt. 4 0% $19,662,792 $16,212,299 $17,868,929 $17,944,304 1% $18,452,579 $15,724,371 $16,802,534 $17,456,376 2% $17,490,419 $15,347,206 $15,949,282 $17,079,211 3% $16,720,706 $15,054,922 $15,263,552 $16,786,928 4% $16,101,215 $14,827,856 $14,710,047 $16,559,862 5% $15,599,695 $14,651,027 $14,261,344 $16,383,032 6% $15,191,367 $14,515,990 $13,896,057 $16,244, Total Cost Millions % 1% 2% 3% 4% 5% 6% Discount Rate Alt. 1 Alt. 2 Alt. 3 Alt. 4

101 Rehabilitation Example Page January 1999 Reference Section 705 Lane Closure Summary* Action Alt. 1 Alt. 2 Alt. 3 Alt. 4 Initial Construction Future 12 Years 15 Years 20 Years 25 Years Years 31 Total of Future Total No. of Days * Lane Closure Summary is for comparison purposes only and is not an estimate of the actual time for construction as many factors exist which were not considered.

102 New Pavement Example Page June 1999 Reference Section 705 New Pavement Type Approval Project: XYZ Date: February 29, 1999 Length: 4.48 miles PID No.: Plans: 10% complete Program Amount: $15,000,000! Flexible Alternative: 1.5" 446 Asphalt Concrete Surface Course, Type 1H 1.75" 446 Asphalt Concrete Intermediate Course, Type 2 7.5" 302 Bituminous Aggregate Base 307 Non-Stabilized Drainage Base Type IA or NJ 408 Bituminous Prime Coat 6" 304 Aggregate Base! Rigid Alternative: Anticipated Future 12 Years: Mill and fill mainline only with Years: Repair 1% of the pavement, mill and overlay with 4 inches 10" 452 Plain Concrete Pavement 307 Non-Stabilized Drainage Base Type IA 408 Bituminous Prime Coat 6" 304 Aggregate Base Anticipated Future 22 Years: Repair 2% full depth and 1% partial depth and grind for smoothness PLEASE INDICATE BELOW YOUR APPROVAL OF ONE OF THE ALTERNATIVES THEN RETURN TO MATERIALS MANAGEMENT Pavement Selection Committee New Design Approval Flexible Rigid District Deputy Director Assistant Director for Transportation Policy Assistant Director for Field Operations Deputy Director of Engineering Policy

103 New Pavement Example Page June 1999 Reference Section 705 Selection Summary Sheet The Flexible Alternative has been selected by the District. The following discussion concerning this selection is provided in an effort to communicate the rational for this decision. Principal Factors LCCA: The Flexible Alternative has the lowest life-cycle cost at all discount rates although the Rigid Alternative is within 5% of it at zero percent discount rate. Initial Cost: The Flexible Alternative has the lowest initial cost and the Rigid Alternative is more than 10% greater. User Delay: The Flexible Alternative has almost twice as many days of lane closure as the Rigid Alternative. This project is located in a rural area with low ADT however, and we don t feel the lane closures will cause any backups or significant disruption to the traveling public and the other factors in favor of the Flexible Alternative outweigh this drawback. Municipal Preference: This project is rural and not located within any municipality. Secondary Factors Geometrics: This project is located on flat terrain with very little grade. There are no geometric constraints which would favor either alternative. Constructability: This project is new pavement on new alignment and any pavement can be constructed easily. Availability of Local Materials: There are currently no available aggregate sources nearby for coarse aggregates which have passed the D-cracking test required for concrete. Other Issues: Our District has had very good performance with flexible pavement the past.

104 New Pavement Example Page June 1999 Reference Section 705 Project Summary 20-year Design ESAL s 24.7 million (Rigid) 16.7 million (Flexible) ADT (1997) 8430 % Trucks (1997) 12 % Functional Classification Rural Principle Arterial Days of Lane Closure* Action Flexible Rigid Initial Construction (Not applicable, new location) Future 12 Years 22 Years Total of Future Maint Total No. of Days * Lane Closure summary is for comparison purposes only and is not an estimate of the actual time for construction as many factors exist which were not considered.

105 New Pavement Example Page June 1999 Reference Section 705 Initial Construction Quantities Costs Item Description Unit Amt. Flexible Rigid Price Flexible Rigid 203 Subgrade Compaction SY 199, ,748 $0.58 $115,854 $115, Bituminous Aggregate Base CY ,709 $44.00 $1,879, Aggregate Base CY 6 35,044 34,167 $21.10 $739,419 $720, Non-Stabilized DB SY 199, ,748 $3.17 $633,202 $633, Tack Coat for Intermediate Gal 14,981 $0.65 $9, Prime Coat Gal 79,899 79,899 $0.84 $67,115 $67, AC Surface, Type 1H CY 1.5 8,323 $68.15 $567, AC Intermediate, Type 2 CY ,710 $43.47 $422, Plain Concrete SY ,748 $21.00 $4,194,714 Total Cost of Initial Construction $4,433,834 $5,731,819 Future Maintenance Quantities Costs Item Description Unit Amt. Flexible Rigid Price Flexible 12 Years 254 Pavement Planing SY 126,157 $0.59 $74, Patching Planed Surface SY 1,262 $2.95 $3, Tack Coat Gal 9,462 $0.71 $6, AC Surface, Type 1H CY 1.5 5,257 $ Years 253 Pavement Repair SY 0.5% 631 $85.97 $54, Pavement Planing SY 199,748 $0.59 $117, Patching Planed Surface SY 1,997 $2.95 $5, Tack Coat Gal 14,981 $0.65 $9, Tack Coat for Intermediate Gal 14,981 $0.65 $9, AC Surface, Type 1H CY 1.5 8,323 $68.15 $567, AC Intermediate, Type 2 CY ,871 $ Years 255 Rigid Repairs SY 2% 2,523 $56.28 $142, Pavement Sawing LF 11,354 $2.17 $24, Bonded Patching SF 1% 11,354 $30.00 $340,623 Spec. Diamond Grinding SY 126,157 $2.44 $307,823 Total Cost of Future Maintenance $1,810,745 $815,086 Total Cost of Alternative $6,244,578 $6,546,905

106 New Pavement Example Page June 1999 Reference Section 705 Sensitivity Analysis of the Discount Rate The Discount Rate is a tool used in evaluating the time value of money. It is broadly defined as the difference between market interest rates and inflation. Because costs are incurred at different points in time over the life of a pavement, the discount rate is used to compare these costs in terms of constant dollars. In this case, 1998 dollars have been used as constant dollars. A survey of states done in the mid 1990's indicated the range of discount rates used throughout the country varies from 0% to 7%. The most common rate used was 4%. Rather than using just one discount rate, a range of rates has been used to show how different rates affect the apparent least cost alternative. Discount Rate Flexible Rigid 0% $6,244,578 $6,546,905 1% $5,925,832 $6,386,656 2% $5,667,862 $6,259,048 3% $5,458,380 $6,157,206 4% $5,287,679 $6,075,749 5% $5,148,099 $6,010,456 6% $5,033,570 $5,958,009 $6,600 $6,400 $6,200 Total Cost Thousands $6,000 $5,800 $5,600 $5,400 $5,200 $5,000 0% 1% 2% 3% 4% 5% 6% Discount Rate Flexible Rigid

107 Appendix A Pavement Design and Selection Process

108

109 Approved: Effective:June10,1999 ResponsibleOffice:MaterialsManagement PolicyNumber: (P) //s//gordonproctor Page1of11 GordonProctor Director PAVEMENT DESIGN AND SELECTION PROCESS POLICY STATEMENT: The Ohio Department of Transportation (ODOT) must select projects and design new pavements and rehabilitations of existing pavements such that they: are structurally adequate to serve the anticipated loadings, employ cost-effective materials, require a minimum amount of maintenance, and result in long-term customer satisfaction. This goal is brought about by assuring a consistent, statewide strategy exists for identifying how resources will be utilized, that proper pavement treatments are applied at the proper time, cost-effective materials are used and best practice construction methodologies are pursued. This Policy will establish uniform procedures to assure that the above objectives are achieved and the experience, collective knowledge, and technical expertise of all involved in the pavement design and selection process are considered. AUTHORITY: The Director of Transportation s authority to establish rules as conferred by of the Ohio Revised Code. REFERENCES: # Pavement Design & Rehabilitation Manual, Ohio Department of Transportation, current revision. # Guide for Design of Pavement Structures, American Association of State Highway and Transportation Officials, # Pavement Rehabilitation Design Training Course - Participants Manual Y.J.Chou, A.A. Morse, D.W. Miller, # Specifications for Subsurface Investigations, Ohio Department of Transportation, November 1, 1995.

110 Policy No (P) Page 2 of 11 # Implementation and Revision of Developed Concepts for ODOT Pavement Management Program--Volume II Pavement Condition Rating Manual, February SCOPE: This policy applies to all multi-lane and all National Highway System (NHS) pavements under the jurisdiction of the Ohio Department of Transportation. Routes other than multilane and NHS are to be managed and designed consistent with fiscal responsibility and sound pavement management practices. Each District Deputy Director will administer this policy, with the approval of the Pavement Selection Committee (PSC) and the Federal Highway Administration (FHWA) when required. The Pavements Section of the Office of Materials Management (Pavements Section) will provide technical assistance, advice, training, and support. DEFINITIONS: Analysis Period - The number of years for which a Life-Cycle Cost Analysis is made. Design Period - The number of years, over which a pavement structure is expected to deteriorate from its initial condition (new or rehabilitated) to its terminal serviceability. The length of this period is directly related to the loading the pavement is expected to carry. Functional Characteristics - Qualities of a pavement such as surface smoothness, skid resistance, and non-load related distresses such as block cracking, and oxidation of asphalt pavement surfaces. Major Rehabilitation - Work performed on a pavement intended to restore structural integrity and functional characteristics. Minor Rehabilitation - Work performed on a pavement intended to restore functional characteristics and protect the structural integrity. Multi-Lane Pavements - Pavements with four or more lanes. Continuous two-way left turn lanes are considered lanes in this definition.

111 Policy No (P) Page 3 of 11 New Pavements - Include those: (1) at a location where no pavement exists beforehand, (2) in the place of an existing pavement removed to a level at or below the top of the subgrade, or (3) being placed next to an existing pavement (widening) for additional highway capacity. Life-Cycle Cost Analysis - A process for evaluating the economic worth of a pavement segment by analyzing initial costs and discounted future costs over a defined period. Pavement Condition Rating (PCR) - A numerical rating of pavement distresses on a 0 to 100 scale based on visual inspection. A PCR of 100 signifies a perfect pavement with no distress. Present Serviceability Index (PSI) - A numerical index which correlates roughness measurements on a scale of 0 to 5. A PSI of 5 indicates an exceptionally smooth pavement. Preventive Maintenance - Work performed on a structurally sound pavement, generally in the form of a surface treatment, intended to preserve the pavement, retard future deterioration, and maintain or improve the functional condition without substantially increasing the structural capacity. Serviceability - Expressed by the Present Serviceability Index. Structural Deduct - An indicator of load-related pavement distress (see Pavement Condition Rating Manual, Volume II ). Structural integrity is measured by the flexural characteristics of a pavement under a load, using nondestructive pavement deflection testing, and indicates the ability of the pavement structure to carry loads. The basic idea being the more a pavement deflects under a load, the less load-carrying capacity. POLICY: I. ORGANIZATION AND RESPONSIBILITIES A. The Pavement Selection Committee (PSC) 1. Will consist of the following persons: a. District Deputy Director (District having jurisdiction) b. Assistant Director for Transportation Policy c. Assistant Director for Field Operations d. Deputy Director of Engineering Policy

112 Policy No (P) Page 4 of The Assistant Director for Transportation Policy will chair the PSC. 3. The PSC: a. Will meet to make decisions based on consensus. b. May call on the District Pavement Designer and/or the Central Office Pavement Section representative to assist the PSC or participate in the meeting. 4. Pavement type selections for new pavements and major rehabilitation projects that exceed four lane-miles (six lane-kilometers) in length, must be approved by the Committee. B. Office of Materials Management - Pavements Section will be responsible for: 1. All policies, manuals, and guidelines concerning pavement design, maintenance, and rehabilitation. 2. Providing advice and assistance to the PSC. 3. Review District Pavement Review Team recommendation and provide concurrence/nonconcurrence documentation to the PSC. 4. Providing technical support, advice, training, and assistance to District personnel involved in development of Work Plans, project scopes, design, and preparation of plans. C. District Offices 1. The Districts will be responsible for all project-related design activities including pavement design, pavement rehabilitation design, and lifecycle cost analysis. 2. The District will be responsible for the development of a comprehensive pavement management strategy as defined in Section IV.F The District will establish a Pavement Review Team which will, at a minimum, consist of:

113 Policy No (P) Page 5 of 11 a. District pavement designer b. Appropriate District Planning, Production and Highway Management personnel. c. County Manager d. A representative from FHWA. 4. The Pavement Review Team will: a. Review all candidate projects in the preventive maintenance, minor rehabilitation and major rehabilitation categories to ensure the proper treatments are being applied to the right roads at the right time. b. Develop a life-cycle cost analysis on all new construction and major rehabilitation projects in accordance with Section II and provide a summary report in accordance with the Pavement Design and Rehabilitation Manual. c. Transmit the report and life-cycle cost analysis (where necessary) to the PSC under the signature of the District Deputy Director and through the Office of Materials Management - Pavements Section. 5. Districts will be responsible for maintaining pavement design records and documentation concerning project decisions for a time period which exceeds the life of the strategy. II. GENERAL A. The results of life-cycle cost analyses will be given thorough consideration in the determination of pavement type for new pavements and major rehabilitations. In addition to the LCCA, the principal and secondary factors to be considered are listed in the table below. Principal Factors Initial Cost User Delay Municipal Preference Secondary Factors Geometrics Constructability Availability of Local Materials

114 Policy No (P) Page 6 of 11 B. Life-cycle cost analyses will use an Analysis Period of 35 years, and will be performed in accordance with the Pavement Design and Rehabilitation Manual. All construction costs anticipated to accrue during the period will be considered in the analyses. III. PROCEDURES FOR NEW PAVEMENTS A. Structural Design Parameters 1. Pavement design will be done following the Pavement Design and Rehabilitation Manual, Sections 200, 300, and New pavements will be designed structurally for a twenty year period using projected equivalent single-axle loadings and appropriate soil support values. B. Pavement Type Selection 1. Procedures to follow for pavement selection vary with the length of the pavement to be constructed. For projects with more than four lanemiles (six-lane kilometers) of mainline pavement, approval of pavement type selection must be obtained from the PSC. Projects that contain less than four lane-miles (six-lane kilometers) need only consensus from the District Pavement Review Team and approval of the District Deputy Director. 2. Projects that require PSC approval also require a Life-Cycle Cost Analysis following current ODOT practice as outlined in Section 700 of the Pavement Design & Rehabilitation Manual. The analysis will include both rigid and flexible alternatives. A completed analysis, indicating the District s preferred alternative, is to be sent to the Pavements Section under the District Deputy Director s signature. The Pavements Section will review the analysis and provide concurrence/nonconcurrence documentation to the PSC. IV. PROCEDURES FOR EXISTING PAVEMENTS A. Network-Level Corrective Action Categories

115 Policy No (P) Page 7 of 11 The Pavement Management System (PMS), managed by the Office of Technical Services, provides a detailed ranking and distress identification for all pavements on a District and Statewide basis. An initial determination for Network-Level Corrective Action Category will be made according to the following table. This table relates corrective actions with the Pavement Condition Rating values predicted to exist at the time any corrective actions are expected to take place. Pavement condition prediction will be based on the latest analysis from ODOT s PMS as detailed in Section 100 of the Pavement Design & Rehabilitation Manual. Any deviations to these categories must be justified and documented in the project- level analysis. Predicted PCR value Network-Level Corrective Action Category * PCR> 85 No action required 85>PCR>75 Preventive maintenance 75>PCR>55 Minor rehabilitation PCR<55 Major rehabilitation * Pavements having a structural deduct greater than or equal to 25 generally require major rehabilitation, no matter of the overall PCR. B. Project-Level Corrective Action Considerations 1. Although the Network-Level Corrective Action Categories provide initial strategies as a function of predicted PCR value, it must be understood that these strategies are for initial estimates only and there will be situations where this framework will not apply. Therefore, it is imperative that each project has a detailed project-level analysis performed before making final detailed design decisions concerning the pavement. 2. The project-level analysis should always begin with a PCR history plot coupled with all available design, construction, and maintenance information regarding the project. A field review to consider all the necessary information for the project-level analysis should be performed by the District Pavement Review Team. The Central Office Pavement Section is available to provide assistance on a case by case basis. C. Preventive Maintenance - General

116 Policy No (P) Page 8 of Preventive Maintenance strategies and techniques are identified in the Pavement Preventive Maintenance Program Guidelines. 2. Preventive Maintenance projects funded under this program (which by definition have only the intention of correcting functional distress, restoring ride quality and extending the service life of the existing pavement structure) will not require design exceptions. 3. Candidate projects will be field reviewed by the Pavement Review Team, after the required project data and analysis has been assembled. The Pavement Review Team will make recommendations regarding appropriate treatments. D. Minor Rehabilitations - General 1. Candidate projects will be field reviewed by the Pavement Review Team, after the required project data and analysis has been assembled. The Pavement Review Team will make recommendations regarding appropriate treatments 2. Design parameters will be determined from the Pavement Design & Rehabilitation Manual. 3. Rehabilitations will be designed structurally for a 12-year period using projected equivalent single-axle loading and dynaflect data. Where analysis shows no structural overlay is required, the project can be considered as preventive maintenance. 4. Upgrading of all roadside appurtenances and appropriate bridge rehabilitations or replacements need to be considered in conjunction with minor rehabilitation projects. 5. Minor rehabilitation strategies will be chosen by the District. E. Major Rehabilitations - General 1. Candidate projects will be field reviewed by the Pavement Review Team, after the required project data and analysis has been assembled. The Pavement Review Team will make recommendations regarding appropriate treatments

117 Policy No (P) Page 9 of Design parameters will be determined using Sections 300, 400, and 600 of the Pavement Design & Rehabilitation Manual 3. Strategies will be designed structurally for a 20-year design period using projected equivalent single-axle loading and dynaflect data. 4. Upgrading of all roadside appurtenances and appropriate bridge rehabilitations or replacements should be done in conjunction with major rehabilitation projects. 5. The following alternative rehabilitation strategies will be considered for major rehabilitations. A Life-Cycle Cost Analysis will be used for comparison purposes. Acceptable strategies include: a. Complete Replacement - Rigid Pavement (required) b. Complete Replacement - Flexible Pavement (required) c. Complete Replacement - Composite Pavement (optional) d. Fractured Slab Techniques: (1) Rubblize & Roll - all concrete pavements and bases (2) Crack & Seat - Plain concrete pavement and base e. Unbonded Concrete Overlay / Whitetopping 6. Strategy Selection will be handled the same as defined for New Pavements, Section III. F. Project Development 1. Each District will be responsible for a ten-year preventive maintenance program and a ten-year minor and major rehabilitation program to be established and updated each year as a part of the District s Work Plan. The ten-year minor and major rehabilitation program shall be determined during the biennial development of the four-year STIP/TIP. These programs shall be sent to the Pavements Section for informational purposes upon the completion of the District s Work Plan. Additionally, the Pavements Section shall be notified of any revisions to these programs throughout the completion of the District s Work Plan. The District s updated program shall indicate the need for

118 Policy No (P) Page 10 of 11 Dynaflect data. Dynaflect data should not be obtained more than four years prior to construction. 2. A reevaluation of the pavement design will be necessary if the project award date surpasses the originally projected date (at the time of pavement analysis) by two years. G. Quality Assurance Reviews 1. The Office of Multi-modal Planning will be the lead office in establishing statewide and district trends in pavement condition. 2. The Office of Materials Management will: H. Training: a. Do quality assurance reviews at the time of construction to determine: (1) Appropriateness of strategy selection (2) Appropriateness of the pavement treatment and design procedure (3) Adherence to this policy b. Share best practices identified by the quality assurance reviews with the districts. c. Identify training needs. The following courses must be included in appropriate personnel s training schedule over a three-year period: 1. Planning and Production Staff: a. Pavement Condition Rating b. Pavement Design Essentials c. Pavement Rehabilitation d. Pavement Type Selection

119 Policy No (P) Page 11 of Highway Management Staff will provide training in appropriate construction techniques (i.e., winter construction schools) I. Fiscal Analysis: 1. The objective of this policy is to implement a strategy that optimizes the combination of pavement preventive maintenance, routine maintenance, rehabilitation, and reconstruction techniques to provide the lowest life-cycle costs consistent with a high level of service to the road users. 2. The strategy depends on implementing a system of preventive maintenance that keeps good roads in good condition. Various national studies have confirmed the effectiveness of a sound preventive maintenance program in reducing the life-cycle costs of pavements while providing a high level of service. 3. Overall, in the short term, this policy is intended to be cost-neutral, neither increasing nor decreasing the level of investment in pavement maintenance and restoration. Initially, investing in preventive maintenance represents a shift in investment funds relative to the prior strategy of only minor and major rehabilitation. Some initial cost reduction will be realized by reducing the minor rehabilitation design period from 20 to 12 years which will balance out over a period of time. Long term benefits in the form of improved levels of serviceability and decreases in the costs of maintaining, rehabilitating, and reconstructing pavements can be expected.

120

121 Appendix B Pavement Guidelines for Treatment of High Stress Locations

122 January1999 PAVEMENT GUIDELINES FOR TREATMENT OF HIGH STRESS LOCATIONS BACKGROUND: These guidelines are intended to be used to reduce or eliminate rutting and or shoving problems associated with the use of asphalt concrete pavement surfaces. These guidelines are intended to be used by District office staff in making best practice decisions regarding pavement resurfacing and design considerations. As there are no previous documents regarding the treatment of rutting and or shoving, it is anticipated there will be numerous questions dealing with special circumstance issues. Technical assistance with these guidelines is available by contacting any of the following individuals: Dave Powers - Asphalt Materials Engineer, Office of Materials Management ( ) Bill Christensen - Flexible Pavement Engineer, Office of Highway Management ( ) Aric Morse - Pavement Design Engineer, Office of Materials Management ( ) DEFINITIONS: Rutting: Rutting is visually identified by vertical depressions in the pavement surface along the wheel tracks. Rutting is measured transversely across the depression using a string line or other appropriate straight edge. Rutting is generally considered significant when it approaches 0.4 inches (~10 mm) in depth. The presence of significant rutting may or may not indicate a high stress location. Circumstances resulting in faulty mix design, production or placement could contribute to rutting. Shoving: Shoving is a longitudinal displacement of a localized area of the pavement surface. It is generally caused by braking or accelerating vehicles, and is usually located on hills, curves, or intersections. Shoving may also include vertical displacement. Shoving is generally considered significant when it affects ride quality. The presence of shoving may or may not indicate a high stress location. Circumstances resulting in faulty mix design, production or placement could contribute to shoving. Medium Traffic: Medium traffic is 50 to 1499 trucks per day using the current year designation. High Traffic: High traffic is 1500 or more trucks per day using the current year designation. High Stress Location: High stress locations are found at areas of high acceleration and braking, at intersections, sharp curves, ramps, and where heavy vehicles frequent at slow speeds. High stress locations occur at intersections with forced stop control and one or more of the following criteria:

123 Appendix B: High Stress Guidelines Page 2 of 3 January 1999! The approach grade to the stop control is greater than or equal to 3.5 percent.! Current Design Designation of 500 trucks per day or greater in the design lane.! Current Design Designation of 250 trucks per day or greater in a turn lane. High stress locations occur on ramps or sharp curves with or without forced stop control which have greater than 250 trucks per day, or have exhibited significant repeated rutting problems in the past. As truck counts on ramps are often unknown, and the definition of a sharp curve depends upon the speed of the curve some judgment is required on new locations. High stress locations occur on stretches of roadway which continue to exhibit significant rutting after several trials of standard mixes. These stretches of roadway generally exhibit rutting due to some combination of long and/or steep grades, trucking/traffic patterns, counts and weights. High stress locations occur at standard bus stops on bus routes or at park and ride lots. High stress locations occur at all truck and bus lots located in the Department s Rest Areas. TREATMENT OF HIGH STRESS LOCATIONS: I. RIGID PAVEMENT: No consideration is made for high stress locations where rigid pavement exists or is proposed. When replacing a composite or flexible pavement with a rigid pavement at a high stress location, the following needs to be considered: A. When new pavement is being constructed, the designer should try to match subgrade elevation at the high stress termini. For most situations, the rigid pavement should be placed on a minimum of 6 inches (~150 mm) of Item 304 Aggregate Base; however, if the surrounding flexible or composite pavement is constructed on subgrade, it would be acceptable to do the same with the rigid pavement. The thickness of the rigid pavement should be a minimum of 8 inches (~200 mm) and a maximum of 15 inches (~375 mm). The exact thickness should be determined by design calculations in accordance with the procedures specified in Section 300 of the Pavement Design & Rehabilitation Manual. B. Where clearance requirements are not a concern, an unbonded concrete overlay may be placed. Unbonded concrete overlays should be constructed a minimum of 8 inches (~200 mm) thick. II. FLEXIBLE PAVEMENT: A. There are several options available for the use of Flexible Pavement in high stress locations. For cost consideration, the Next Step approach should be used. Next Step approaches are as follows:

124 Appendix B: High Stress Guidelines Page 3 of 3 January In a high stress area which would otherwise require a medium traffic pavement mix design, specify a heavy traffic pavement mix design. All high stress areas using a Type 1H design shall use Item 446 regardless of the quantity limitations given in Section In a high stress area which would otherwise require a heavy traffic pavement mix design, specify a non-standard modified asphalt concrete pavement mix design. A list of all available modified asphalt concrete mixes is on file with the Office of Materials Management. Contact the Asphalt Materials Section for a current list of available options. B. For all high stress locations where rutting is evident, pavement planing should be specified to remove all deformed material. 1. For flexible pavement, planing should be specified to the bottom of the material responsible for the rutting. In order to determine the responsible layer, the comparison of pavement cores taken in the rutted area with cores taken outside of the rut may be helpful. Where this information is not available, best practice is to remove up to 3 inches (~75 mm) below the deepest portion of the rut. Standard practice concerning tack coat should be followed prior to the placement of the Next Step asphalt mixes. 2. For composite pavement, planing should be specified as per II.B.1. Where the surface of the rigid base pavement is within 2 inches (~50mm) of the required milled depth, best practice is to take the milling down to the concrete, in order to provide a course of larger aggregate (301 or 302) material. C. Lift combinations and thickness requirements will generally be the same as would be required for a standard flexible pavement or overlay. LIMITS OF HIGH STRESS LOCATIONS: The limits of the high stress treatment should be determined as follows: A. A minimum of 250 feet (~75 m) back from the location of stop termini or traffic signal. B. The length of the turn lane. C. The limits of the existing problem condition. In urban areas where several intersections exist within close proximity to each other and meet high stress criteria, best practice is to specify the required high stress mix the length of the section bounded at the outermost limits of the high stress locations.

125 Appendix C Simplified Pavement Design for Short Projects

126 Simplified Pavement Designs for Short Projects Many projects exist such as bridge replacement projects which include a short stretch of new pavement or pavement replacement. For projects in which the total length of new pavement or pavement replacement is less than 300 feet (~100 m), the chart on the following page may be used in lieu of a complete pavement design per Sections 200, 300 and 400 of this Manual. The buildups given on the chart are conservative and are based on the amount of truck traffic expected for the opening day. The following procedures and precautions should be recognized: 1. The length of pavement replacement is exclusive of bridge length, where applicable. 2. The designer should first evaluate the buildup of the existing pavement. If the strength of the existing pavement exceeds the chart value, then the existing design should be perpetuated. 3. Where opening day truck traffic exceeds 800, this chart is not to be used and the procedures described in Sections 200, 300 and 400 of this Manual are to be followed. 4. If it is known in advance that poor soils may be encountered at subgrade level or if the designer is unsure of proper subgrade or slope treatments, review by the Geotechnical Design Section of the Office of Materials Management is recommended. 5. The designer is always welcome to do a complete design per Sections 200, 300 and 400 rather than using the chart.

127 Simplified Pavement Designs for Short* Projects Pavement Course Thicknesses Number of Trucks in Opening Day ADT Pavement Composition (ADT x T24) <= >800 in. ~mm in. ~mm in. ~mm in. ~mm in. ~mm in. ~mm in. ~mm Flexible Design 448 AC Surface, Type 1, PG n/a 448 AC Intermediate, Type 2, PG n/a 301 Bituminous Aggregate Base n/a 408 Bituminous Prime Coat r r r r r r p p p p p p p p n/a 304 Aggregate Base n/a Alternate Flexible Design 448 AC Surface, Type 1, PG n/a 448 AC Intermediate, Type 2, PG n/a 408 Bituminous Prime Coat r r n/a 304 Aggregate Base n/a Rigid Design 452 Plain Concrete Pavement n/a 304 Aggregate Base n/a * Less than 300 linear feet (~100 meters) of total pavement replacement r - required p - optional

128 Appendix D ODOT s PCR Manual

129 PAVEMENT CONDITION RATING SYSTEM REVIEW OF PCR METHODOLOGY Report No. FHWA/OH-99/004 Prepared by Resource International, Inc. 281 Enterprise Drive Westerville, Ohio March, 1998

130 1. Report No. 2. Government Accession Number 3. Recipients Catalog No. FHW A/OH-99/ Title and Subtitle PAVEMENT CONDITION RATING SYSTEM REVIEW OF PCR METHODOLOGY 5. Repo rt Date March, Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Chhote L. Saraf 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Resource International, Inc. 281 Enterprise Drive Westerville, OH Contract or Grant No. State Job No (0) 12. Sponsoring Organization Name and Address Ohio Department of Transportation 1600 West Broad Street Columbus, OH Type of Report & Period Covered Manual 14. Sponsoring Agency Code 15. Supplementary Notes Prepared in cooperation with the U.S. Department of Transportation, Federal Highway Administration 16. Abstract This repo rt des cribe s the Pave me nt Co ndition Ra ting m ethod which was de velop ed fo r the S tate of Ohio High way N etwo rk. T he m ethod is ba sed upon visua l inspe ction of pavem ent distres ses. Altho ugh the re lationship between pavement distresses and performance is not well defined, there is general agreement that the ability of a pavement to sustain traffic loads in a safe and smooth manner is adversely affected by the occurrence of observable distress. The rating method described in this report provides a procedure for uniformly identifying and describing, in terms of severity and extent, pavement distress. The mathematical expression for pavement condition rating (PC R) provides an ind ex reflecting the compo site effects of various distress types, their severity and extent upon the overa ll condition of the pavem ent. Distresses of four (4) types of Pave me nts (F lexible, Com posite, Jo inted Con crete and C ontinuously Reinforced or CRC) are described in this report and each distress is illustrated with the help of photographs. 17. Key Words Pavement Condition Rating, Flexible Pavements, Composite Pavements, Jointed Concrete Pavements, Continuously Reinforced Concrete Paveme nts 18. Distribution Statement No Restrictions. This document is available to the public through the National Technical Information Service, Springfield, Virginia Security Class (This Report) Unclassified 20. Security Class (This Page) Unclassified Form DOT F (8-72) Reproduction of completed page authorized 21. No. of Pages 22. Price

131 DISCLAIMER The contents of this report reflect the views of the authors, who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Ohio Department of Transportation or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. i

132 ACKNOWLEDGMENTS This is Volume II of the final draft report of research project 3628, entitled Implementation and Revision of Developed Concepts for ODOT Pavement Management Program, which was conducted by Resource International, Inc. The financial support for this project was provided by the U.S. Department of Transportation, Federal Highway Administration, and the Ohio Department of Transportation. This study was carried out in cooperation with the Ohio Department of Transportation. The authors with to express their sincere appreciation to Messrs. Leon O. Talbert, Engineer of Research and Development; Ken Miller, Engineer of Pavement and Soils; Anthony Manch, Engineer of Pavement Management; Jim McQuirt, Planning Research Engineer; Roger Green, Design Engineer, and the many other members of the Ohio Department of Transportation for their invaluable assistance in conducting this study. The authors also wish to extend appreciation to E. Rouch of the Federal Highway Administration for his valuable suggestions during the review of this report. Special acknowledgments are due to Jack Holbrook for editing and production of this manuscript and to Donna Roberts and Margaret Larcomb for preparing and typing it. The revision of this manual was performed under the project A Review of PCR Methodology for the Ohio DOT, State Job Number 14638(0). This report is made possible through the help and support received from the Ohio Department of Transportation staff, Messrs. Roger Green, Kenneth Corns, Andrew Williams, Aric Morse, Dave Miller, and Murphy Hsu. Most of the photographs have been revised and the original photographs are in color now. The sources of these photographs are listed in Appendix E. ii

133 TABLE OF CONTENTS Page DISCLAIMER... i ACKNOWLEDGMENTS... ii PAVEMENT CONDITION RATING PROCEDURES...1 INTRODUCTION...1 FIELD MONITORING PROCEDURE...4 PAVEMENT CONDITION RATING FORMS AND KEY FORMS...5 Key - Flexible Pavement Condition Rating Form...6 Flexible Pavement Condition Rating Form...7 Key - Composite Pavement Condition Rating Form...8 Composite Pavement Condition Rating Form...9 Key - Jointed Concrete Pavement Condition Rating Form...10 Jointed Concrete Pavement Condition Rating Form...11 Key - CRC Pavement Condition Rating Form...12 CRC Pavement Condition Rating Form...13 APPENDIX A. Description of Distresses in Flexible Pavements... A-1 Raveling... A-2 Bleeding... A-4 Patching... A-6 Potholes/Debonding... A-8 Crack Sealing Deficiency... A-10 Rutting... A-12 Settlement... A-14 Corrugations... A-16 Wheel Track Cracking... A-18 Block and Transverse Cracking... A-20 Longitudinal Joint Cracking... A-22 Edge Cracking... A-24 Random Cracking... A-26 iii

134 Page APPENDIX B. Description of Distresses in Composite Pavements...B-1 Raveling...B-2 Bleeding...B-4 Patching...B-6 Surface Disintegration or Debonding...B-8 Rutting...B-10 Corrugations...B-12 Pumping...B-14 Shattered Slab...B-16 Settlement...B-18 Transverse Cracking...B-20 Severity Level: Unjointed Base or Jointed Base...B-20 Extent Level: Jointed Base - Intermediate Transverse Cracking...B-22 Extent Level: Unjointed Base...B-22 Extent Level: Jointed Base-Joint Reflection Cracks...B-22 Longitudinal Cracking...B-24 Pressure Damage/Upheaval...B-26 Crack Sealing Deficiency...B-28 APPENDIX C. Description of Distresses in Jointed Reinforced Concrete or Jointed Plain Concrete Pavements (JRC/JPC Pavements)...C-1 Surface Deterioration...C-2 Popouts...C-4 Patching...C-6 Pumping...C-8 Faulting...C-10 Settlement...C-12 Transverse Joint Spalling...C-14 Joint Sealant Damage...C-16 Pressure Damage...C-18 Transverse Cracking...C-20 Longitudinal Cracking...C-22 Corner Breaks...C-24 APPENDIX D. Description of Distresses in Continuously Reinforced Concrete Pavements (CRCP)... D-1 Surface Deterioration... D-2 Popouts... D-4 iv

135 Page Patching... D-6 Pumping... D-8 Settlements and Waves... D-10 Transverse Crack Spacing... D-12 Longitudinal Cracking... D-14 Punchouts or Edge Breaks... D-16 Spalling... D-18 Pressure Damage... D-20 APPENDIX E. Sources of Photographs used in Appendices A - D...E-1 Abbreviations used in the Tables...E-2 LIST OF TABLES Table E-1. Table E-2. List of Sources of Photographs of Appendix A and B...E-3 List of Sources of Photographs of Appendix C and D...E-4 LIST OF FIGURES Figure 1. Pavement Condition Rating (PCR) Scale...3 v

136 APPENDIX A. LIST OF PHOTOGRAPHS Description of Distresses in Flexible Pavements Page Photo A-1. Raveling in Flexible Pavement, Medium Severity... A-3 Photo A-2. Raveling in Flexible Pavement, High Severity... A-3 Photo A-3. Bleeding in Flexible Pavement, High Severity... A-5 Photo A-4. Close-up view of Bleeding, High and Medium Severity... A-5 Photo A-5. Patching in Flexible Pavement, High Severity... A-7 Photo A-6. Patching in Flexible Pavement, High Severity... A-7 Photo A-7. Pothole in Flexible Pavement, Medium Severity... A-9 Photo A-8. Debonding in Flexible Pavement, Medium Severity... A-9 Photo A-9. Crack Sealing Deficiency in Flexible Pavement, Unsealed Cracks... A-11 Photo A-10. Crack Sealing Deficiency in Flexible Pavement, Cracks not sealed properly A-11 Photo A-11. Rutting in Flexible Pavement, Medium Severity... A-13 Photo A-12. Rutting in Flexible Pavement, High Severity... A-13 Photo A-13. Settlement, Low Severity... A-15 Photo A-14. Settlement, Medium Severity... A-15 Photo A-15. Corrugations in Flexible Pavement, Medium Severity... A-17 Photo A-16. Wheel Track Cracking in Flexible Pavement, Med. Severity... A-19 Photo A-17. Wheel Track Cracking in Flexible Pavement, High Severity... A-19 Photo A-18. Block and Transverse Cracking in Flexible Pavement, Medium Severity.. A-19 Photo A-19. Block and Transverse Cracking in Flexible Pavement, High Severity... A-19 Photo A-20. Longitudinal Joint Cracking in Flexible Pavement, Medium Severity... A-23 Photo A-21. Longitudinal Joint Cracking in Flexible Pavement, High Severity... A-23 Photo A-22. Edge Cracking in Flexible Pavement, Medium Severity... A-25 Photo A-23. Edge Cracking in Flexible Pavement, High Severity... A-25 Photo A-24. Random Cracking in Flexible Pavement, Medium Severity... A-27 vi

137 APPENDIX B. LIST OF PHOTOGRAPHS Description of Distresses in Composite Pavements Page Photo B-1. Photo B-2. Photo B-3. Photo B-4. Photo B-5. Photo B-6. Photo B-7. Photo B-8. Photo B-9. Photo B-10. Raveling in Composite Pavement, Medium Severity...B-3 Raveling in Composite Pavement, High Severity...B-3 Bleeding, High Severity...B-5 Close-up view of Bleeding, High and Medium Severity...B-5 Patching in Composite Pavement, Medium Severity...B-7 Patching in Composite Pavement, High Severity...B-7 Surface Disintegration in Composite Pavement...B-9 Debonding in Composite Pavement, Medium Severity...B-9 Rutting, Medium Severity...B-11 Rutting, High Severity...B-11 Photo B-10a. Corrugations in Composite Pavement...B-13 Photo B-11. Photo B-12. Photo B-13. Photo B-14. Photo B-15. Photo B-16. Photo B-17. Photo B-18. Photo B-19. Photo B-20. Photo B-21. Photo B-22. Pumping in Composite Pavement, Medium Severity...B-15 Pumping in Composite Pavement, High Severity...B-15 Shattered Slab of Composite Pavement, High Severity...B-17 Settlement in Composite Pavement, Medium Severity...B-19 Unjointed Base, Transverse Cracking in Composite Pavement, Low Severity...B-21 Unjointed Base, Transverse Cracking in Composite Pavement, High Severity...B-21 Jointed Base, Reflection Cracking in Composite Pavement, Medium Severity...B-23 Jointed Base, Reflection Cracking in Composite Pavement, High Severity..B-23 Longitudinal Cracking in Composite Pavement, High Severity...B-25 Pressure Damage/Upheaval in Composite Pavement, Medium Severity...B-27 Crack Sealing Deficiency, Unsealed Cracks...B-29 Crack Sealing Deficiency, Cracks not sealed properly...b-29 vii

138 APPENDIX C. LIST OF PHOTOGRAPHS Description of Distresses in Jointed Reinforced Concrete or Jointed Plain Concrete Pavements (JRC/JPC Pavements) Page Photo C-1. Photo C-2. Photo C-3. Photo C-4. Photo C-5. Photo C-6. Photo C-7. Photo C-8. Photo C-9. Photo C-10. Photo C-11. Photo C-12. Photo C-13. Photo C-14. Photo C-15. Photo C-16. Photo C-17. Photo C-18. Photo C-19. Photo C-20. Photo C-21. Photo C-22. Photo C-23. Surface Deterioration in Jointed Concrete Pavement, Medium Severity...C-3 Surface Deterioration in Jointed Concrete Pavement, High Severity...C-3 Popout in Jointed Concrete Pavement, Plan and Cross-sectional Views...C-5 Popouts in a Jointed Concrete Pavement...C-5 Patching in Jointed Concrete Pavement, Low Severity...C-7 Patching in Jointed Concrete Pavement, High Severity...C-7 Pumping in Jointed Concrete Pavement, High Severity...C-9 Pumping in Jointed Concrete Pavement, Low Severity...C-9 Sketch showing Faulting in Jointed Concrete Pavement...C-11 Faulting in Jointed Concrete Pavement...C-11 Settlements in Jointed Concrete Pavement, Medium Severity...C-13 Transverse Joint Spalling in Jointed Concrete Pavement, Low Severity...C-15 Transverse Joint Spalling in Jointed Concrete Pavement, High Severity...C-15 Joint Sealant Damage in Jointed Concrete Pavement...C-17 Joint Sealant Damage in Jointed Concrete Pavement...C-17 Pressure Damage in Jointed Concrete Pavement...C-19 Pressure Damage in Jointed Concrete Pavement...C-19 Transverse Cracking in Jointed Concrete Pavement, Low Severity...C-21 Transverse Cracking in Jointed Concrete Pavement, High Severity...C-21 Longitudinal Cracking in Jointed Concrete Pavement, Medium Severity...C-23 Longitudinal Cracking in Jointed Concrete Pavement, Medium Severity...C-23 Corner Break in Jointed Concrete Pavement, Medium Severity...C-25 Corner Break in Jointed Concrete Pavement, High Severity...C-25 viii

139 APPENDIX D. LIST OF PHOTOGRAPHS Description of Distresses in Continuously Reinforced Concrete Pavements (CRCP) Page Photo D-1. Surface Deterioration in CRC Pavement, Medium Severity... D-3 Photo D-2. Surface Deterioration in CRC Pavement, High Severity... D-3 Photo D-3. Popout in CRC Pavement, Plan and Cross-sectional Views... D-5 Photo D-4. Popouts in CRC Pavement... D-5 Photo D-5. Patching in CRC Pavement, Low Severity... D-7 Photo D-6. Patching in CRC Pavement, High Severity... D-7 Photo D-7. Pumping in CRC Pavement, Medium Severity... D-9 Photo D-8. Pumping, High Severity... D-9 Photo D-9. Settlement in CRC Pavement... D-11 Photo D-10. Transverse Cracks in CRC Pavement, Low Severity... D-13 Photo D-11. Transverse Cracks in CRC Pavement, Medium Severity... D-13 Photo D-12. Longitudinal Cracking in CRC Pavement, Medium Severity... D-15 Photo D-13. Longitudinal Cracking in CRC Pavement, High Severity... D-15 Photo D-14. Punchouts in CRC Pavement, Medium Severity... D-17 Photo D-15. Punchouts in CRC Pavement, High Severity... D-17 Photo D-16. Spalling in CRC Pavement, Medium Severity... D-19 Photo D-17. Spalling in CRC Pavement, High Severity... D-19 Photo D-18. An Example of Pressure Damage in Jointed Concrete Pavement, Pressure Damage in CRCP is similar to as shown above... D-21 ix

140 PAVEMENT CONDITION RATING PROCEDURES INTRODUCTION The rating method is based upon visual inspection of pavement distress. Although the relationship between pavement distress and performance is not well defined, there is general agreement that the ability of a pavement to sustain traffic loads in a safe and smooth manner is adversely affected by the occurrence of observable distress. The rating method provides a procedure for uniformly identifying and describing, in terms of severity and extent, pavement distress. The mathematical expression for pavement condition rating (PCR) provides an index reflecting the composite effects of varying distress types, severity, and extent upon the overall condition of the pavement. The model for computing PCR is based upon the summation of deduct points for each type of observable distress. Deduct values are a function of distress type, severity, and extent. Deduction for each distress type is calculated by multiplying distress weight times the weights for severity and extent of the distress. Distress weight is the maximum number of deductible points for each different distress type. The mathematical expression for PCR is as follows: Where: n PCR = Deduct i (1) I=1 n = number of observable distresses, and Deduct = (Weight for distress) (Wt. for severity) (Wt. for Extent) The Appendices A-D that follow describe various distresses for rigid, flexible, and composite pavements and current guidelines for establishing their severity and extent. Three levels of severity (Low, Medium and High) and three levels of extent (Occasional, Frequent, and Extensive) are defined. The definition for distress type, severity, and extent must be followed closely and be clearly understood by field personnel if the rating method is to provide meaningful data. To illustrate the method for calculating PCR, consider the distress Faulting in a hypothetical jointed concrete pavement. If the severity of this distress in the pavement is Medium and extent is Frequent, then, the deduct points for Faulting in the pavement would be equal to [(10) (0.7) (0.8)] or 5.6 (see Table on page 11 for the weights of this distress). If an extensive amount of medium severity Surface Deterioration is also observed the deduct points for this distress would be equal to [(10) (0.7) (1)] or 7.0. The PCR for the pavement based upon these 2 distresses would equal to: PCR = ( ) = 87.4 (2) 1

141 The deduct weights for each pavement type have been developed on the basis of the review of the rating methods developed in the United States, Europe, and Canada and the experience gained from the rating methods developed by the Resource staff as a result of studies conducted in this connection. Two premises were considered when assigning the weights: 1. Overlaying and/or rehabilitation of high type (multi-lane) roadways should be considered when the PCR drops within the range of 65 to Deteriorated pavements normally exhibit several different types of distress. Rarely is only a single type of distress observed for a particular pavement. The first premise is useful in establishing a target value for the proper PCR of pavements that are in a certain state or condition. Roadways scheduled for rehabilitation and resurfacing have to be rated by the PCR procedure. A Pavement Condition Rating (PCR) Scale was developed to describe the pavement condition using the PCR numbers calculated from Equation (1). This scale has a range from 0 to 100; a PCR of 100 represents a perfect pavement with no observable distress and a PCR of 0 represents a pavement with all distress present at their High levels of severity and Extensive levels of extent. Figure 1 illustrates the PCR Scale and the descriptive condition of a pavement associated with the various ranges of the PCR values. 2

142 PCR Condition 100 Very Good 90 Good 75 Fair 65 Fair to Poor 55 Poor 40 Very Poor 0 Figure 1. Pavement Condition Rating (PCR) Scale 3

143 FIELD MONITORING PROCEDURE The pavement condition rating is intended to apply to the entire pavement section being monitored. Section lengths are established by the monitoring procedure, with the average length being from 3 to 5 km (2 to 3 miles). Directional lanes of multilane roadways are considered separate roadways by the monitoring procedure. On multilane roadways the heaviest traveled lane (usually the outside lane) should be rated. For two lane roadways, rating one direction is sufficient unless a significant difference in condition is observed between the two lanes. The monitoring procedure checks the variance of the Pavement Serviceability Index (PSI) within a section to limit section length. This limitation should produce sections that have a fairly constant visual condition. If a definite variation in condition is observed within a section, the section should then be subdivided for condition rating. Recording of visible distress for the PCR calculations involves three steps: Step 1. Step 2. Step 3. The rating team (the rating team should consist of a Driver and a Rater) should ride the predetermined roadway section at a speed of about 60 km (40 MPH). During this step, readily visible distresses such as potholes, bleeding, settlement, faulting, spalling, and surface deterioration should be rated. Also the need for subdividing the section should be evaluated in step 1. A second pass along the roadway section should be made with stops at approximately 1.5 km (1 mile) intervals. For example, a 3 km (2-mile section) would require 2 stops to be made. At each stop the raters should evaluate the roadway by viewing 30 m (100') of the pavement. Close inspection of pavement cracking, crack sealing, rutting, raveling, joint spalling, D-cracking, and other visible distress should be made by viewing the pavement from the roadway shoulder. Complete the PCR form. The final rating form for the roadway section should represent the observed average of visible distress for the entire section. Separate rating forms based upon the step 1 observations and the individual stops made during step 2 are not required. However, raters may wish to use additional rating forms for each stop, simply for note keeping purposes. 4

144 PAVEMENT CONDITION RATING FORMS AND KEY FORMS Note: The Key forms summarize data presented in Appendices A through D. These key forms will aid field personnel in establishing distress severity and extent while performing the PCR surveys. 5

145 Section: KEY Date: Log Mile: to FLEXIBLE PAVEMENT CONDITION Rated by: Sta: to RATING FORM DISTRESS Distress Weight RAVELING 10 SEVERITY* EXTENT** STR L M H O F E *** Slight Loss of Sand Open Texture Rough or pitted <20% 20-50% >50% BLEEDING 5 not rated Bit and Agg visible Black Surface <10% 10-30% >30% PATCHING 5 <1 ft 2. <1 yd 2 >1 yd 2 <10/mile /m ile >20/mile POTHOLES/DEBONDING 10 depth <1" <1", > 1 yd 2 >1" and area <1 yd 2 >1",< 1 yd 2 >1 yd 2 <5/m ile 5-10 /mile >10/mile CRACK SEALING DEFIC. 5 Not considered <20% 20-50% >50% RUTTING 10 <1/4" 1/4-1" >1" <20% 20-50% >50% SETTLEMENTS 10 CORRUGATIONS 5 WHEEL TRACK CRACKING BLOCK & TRANSVERSE CRACKING LONGITUDINAL JOINT CRACKING Notic eable effect on ride Notic eable effect on ride Single/m ultiple cracks <1/4" <1/4" wide, no Spalling Single, <1/4", no Spalling Some Discomfort Some Discomfort Multiple cracks >1/4" 1/4-1" along min.5 len gth single/m ultiple 1/4-1", some Spalling Poor Ride <2/mi 2-4/m i >4/mi Poor Ride <10% 10-30% >30% Alligator >1/4" Spalling >1" along m in.5 length Multiple, >1", Spalling <20% 20-50% >50% <20% 20-50% >50% <20% 20-50% >50% >1/4", >1/4", some EDGE CRACKING 5 Tight, <1/4" mod erate <20% 20-50% >50% Spalling Spalling RANDOM CRACKING 5 <1/4" 1/4-1" >1" <20% 20-50% >50% *L = LOW **O = OCCASIONAL ***STR = DISTRESS INCLUDED IN STRUCTURAL DEDUCT CALCULATIONS. M = MEDIUM F = FREQUENT H = HIGH E = EXTENSIVE 6

146 Section: Log mile: to Sta: to DISTRESS FLEXIBLE PAVEMENT CONDITION RATING FORM DISTRESS WEIGHT Date: Rated by: SEVERITY WT.* EXTENT WT.** DEDUCT POINTS*** L M H O F E RAVELING BLEEDING PATCHING POTHOLES/DEBONDING CRACK SEALING DEFICIENCY RUTTING SETTLEMENT CORRUGATIONS WHEEL TRACK CRACKING BLOCK AND TRANSVERSE CRACKING LONGITUDINAL JOINT CRACKING EDGE CRACKING RANDOM CRACKING *L = LOW **O = OCCASIONAL TOTAL DEDUCT = M = MEDIUM F = FREQUENT SUM OF STRUCTURAL DEDUCT ( ) = H = HIGH E = EXTENSIVE TOTAL DEDUCT = PCR = *** DEDUCT POINTS = DISTRESS WEIGHT X SEVERITY WT. X EXTENT WT. REMARKS: 7

147 Section: KEY Date: Log Mile: to COMPOSITE PAVEMENT CONDITION Rated by: Sta: to RATING FORM DISTRESS Distress Weight RAVELING 10 SEVERITY* EXTE NT** STR L M H O F E *** Slight Loss of Sand Open Texture Rough or Pitted <20% 20-50% >50% BLEEDING 5 not rated Bitumen & Agg. Visible Black Surface <10% 10-30% >30% PATCHING 5 <1 ft 2 <1 yd 2 >1 yd 2 <10/mile /m ile >20/mile SURFACE DISINTEGRATION/ DEBONDING 5 depth <1" <1", > 1 yd 2 >1" and area <1 yd 2 >1",< 1 yd 2 >1 yd 2 <5/m ile 5-10 /mile >10/mile RUTTING 10 <1/4" 1/4-1" >1" <20% 20-50% >50% CORRUGATIONS 5 Notic eable effect on ride PUMPING 10 Slight Staining SHATTERED SLAB 10 SETTLEMENTS 5 TRANSVERSE CRACKS, UNJOINTED BASE JOINT REFLECTION CRACKS, JOINTED BASE INTERMEDIATE TRANSVERSE CRACKS, JOINTED BASE Longitudinal Cracking 5 Pressure Damage/ Upheaval Little S pall, No Faults Notic eable effect on ride <1/4", no spalling <1/4", no spalling <1/4", no spalling <1/4", no spalling bum p <½", Good Ride Some Discomfort Som e Spall. Mode rate Faults Some Discomfort 1/4-1", >.5 spalled 1/4-1", >.5 spalled 1/4-1", >.5 spalled 1/4-1", >.5 spalled ½-1", Fair Ride Poor Ride <10% 10-30% >30% excessive staining, fa ult Severe Distortion, Poor Ride <10% 10-25% >25% <2/mi 2-5/m i >5/mi Poor Ride <2/mi 2-4/m i >4/mi >1", >.5 spalled >1", >.5 spalled >1", >.5 spalled >1", >.5 spalled >1", Poor Ride CS>15' 10'<CS<15' CS<10' <20% 20-50% >50% CS>15' 10'<CS<15' CS<10' <50' per 100' ' per 100' >150' per 100' <20% 20-50% >50% Crack Sealing Deficiency 5 Not considered <20% 20-50% >50% *L = LOW **O = OCCASIONAL ***STR = DISTRESS INCLUDED IN STRUCTURAL DEDUCT CALCULATIONS. M = MEDIUM F = FREQUENT H = HIGH E = EXTENSIVE 8

148 Section: Log mile: to Sta: to DISTRESS COMPOSITE PAVEMENT CONDITION RATING FORM DISTRESS WEIGHT Date: Rated by: SEVERITY WT.* EXTENT WT.** DEDUCT POINTS*** L M H O F E RAVELING BLEEDING PATCHING SURFACE DISINTEGRATION or DEBONDING RUTTING CORRUGATIONS PUMPING SHATTERED SLAB SETTLEMENTS TRANSVERSE CRACKS, UNJOINTED BASE JOINT REFLECTION CRACKS, JOINTED BASE INTERMEDIATE TRANSVERSE CRACKS, JOINTED BASE LONGITUDINAL CRACKING PRESSURE DAMAGE/UPHEAVAL CRACK SEALING DEFICIENCY *L = LOW **O = OCCASIONAL TOTAL DEDUCT = M = MEDIUM F = FREQUENT SUM OF STRUCTURAL DEDUCT ( ) = H = HIGH E = EXTENSIVE TOTAL DEDUCT = PCR = *** DEDUCT POINTS = DISTRESS WEIGHT X SEVERITY WT. X EXTENT WT. REMARKS: 9

149 Section: KEY Date: Log Mile: to JOINTED CONCRETE PAVEMENT Rated by: Sta: to CONDITION RATING FORM DISTRESS Distress Weight SEVERITY WEIGHT* EXTE NT W EIGHT ** L M H O F E STR *** SURFACE DETERIORATION 10 Aggregate visible Loss of fine aggregate Surface rough or pitted <20% 20-50% >50% POPOUTS 5 Not considered <20% 20-50% >50% PATCHING 5 <1 ft 2, no deterioration. <1 ft 2, deterioration. >1 ft 2 <10/mi 10-20/m i >20/mi PUMPING 15 some staining, rater is certain of pumping excessive staining <10% 10-25% >25% FAULTING (Joints & Cracks) 10 <1/4" 1/4-1/2" >½" <20% 20-50% >50% SETTLEMENTS 5 Notic eable effect on Ride Some discomfort Poor Ride 2/m i. 2-4/m i. >4/m i. TRANSVERSE JOINT SPALLING 15 <4" wide 4-9" wide >9" wide <25% 25-75% 75% JOINT SEALANT DAMAGE 5 Not considered <20% 20-50% 50% PRESSURE DAMAGE 5 Not considered <1/mi 1-3/m i >3/mi TRANSVERSE CRACKING 10 Hairline 1/4-1" >1 CS>15' 10<CS<15' CS<10' LONGITUDINAL CRACKING 5 Hairline 1/4-1" >1" <5% 5-20% >20% CORNER BREAKS 10 <1/4" 1/4-1 >1" 3/mi 4-10 /mi. >10 m i. *L = LOW **O = OCCASIONAL ***STR = DISTRESS INCLUDED IN STRUCTURAL DEDUCT CALCULATIONS. M = MEDIUM F = FREQUENT H = HIGH E = EXTENSIVE 10

150 Section: Log mile: to Sta: to DISTRESS JOINTED CONCRETE Date: Rated by: PAVEMENT CONDITION RATING FORM DISTRESS WEIGHT SEVERITY WT.* EXTENT WT.** DEDUCT POINTS*** L M H O F E SURFACE DETERIORATION POPOUT PATCHING PUMPING FAULTING (JOINTS AND CRACKS) SETTLEMENTS TRANSVERSE JOINT SPALLING (CIRCLE IF D-CRACKED) JOINT SEALANT DAMAGE PRESSURE DAMAGE TRANSVERSE CRACKING LONGITUDINAL CRACKING CORNER BREAKS *L = LOW **O = OCCASIONAL TOTAL DEDUCT = M = MEDIUM F = FREQUENT SUM OF STRUCTURAL DEDUCT ( ) = H = HIGH E = EXTENSIVE TOTAL DEDUCT = PCR = *** DEDUCT POINTS = DISTRESS WEIGHT X SEVERITY WT. X EXTENT WT. REMARKS: 11

151 Section: KEY Date: Log Mile: to CRC PAVEMENT CONDITION Rated by: Sta: to RATING FORM DISTRESS SURFACE DETERIORATION DISTRESS WEIGHT 10 SEVERITY WEIGHT* EXTE NT W EIGHT ** STR L M H O F E *** Aggregate visible Loss of fine aggregate Surface rough or pitted <20% 20-50% >50% POPOUTS 5 Not considered <20% 20-50% >50% PATCHING 5 PUMPING 15 SETTLEMENTS & W AVES 10 TRANSVERSE CRACK SPACING <1 ft 2, no deterioration <1 ft 2, deterioration some staining, rater is certain of pumping Notic eable effect on Ride Some discomfort 10 CS 3-5' CS <3' >1 ft 2 <10/mi 10-20/m i >20/mi excessive staining Poor Ride CS <3' Many cracks intersect <10% 10-25% >25% <2/m i. (<20%) 2-4/m i 20-50% >4/mi (>50%) <20% 20-50% >50% LONGITUDINAL CRACKING 10 Hairline >1/4" - 1" >1" <5% 5-15% >15% PUNCHOUTS & EDGE BREAKS SPALLING Not rated <1", few pieces missing cracks <1/4" depress <½" 1-4" wide, most pieces missing depress >½" Breaking up >4" wide, most pieces missing <2/m i. 2-5/m i >5/mi <20% 20-50% >50% PRESSURE DAMAGE 5 Not considered <1/m i. 1-3/m i. >3/m i. *L = LOW **O = OCCASIONAL ***STR = DISTRESS INCLUDED IN STRUCTURAL DEDUCT CALCULATIONS. M = MEDIUM F = FREQUENT H = HIGH E = EXTENSIVE 12

152 Section: Log mile: to Sta: to DISTRESS C R C PAVEMENT CONDITION RATING FORM DISTRESS WEIGHT Date: Rated by: SEVERITY WT.* EXTENT WT.** DEDUCT POINTS*** L M H O F E SURFACE DETERIORATION POPOUT PATCHING PUMPING SETTLEMENTS & WAVES TRANSVERSE CRACK SPACING LONGITUDINAL CRACKING PUNCHOUTS OR EDGE BREAKS SPALLING PRESSURE DAMAGE *L = LOW **O = OCCASIONAL TOTAL DEDUCT = M = MEDIUM F = FREQUENT SUM OF STRUCTURAL DEDUCT ( ) = H = HIGH E = EXTENSIVE TOTAL DEDUCT = PCR = *** DEDUCT POINTS = DISTRESS WEIGHT X SEVERITY WT. X EXTENT WT. REMARKS: 13

153 APPENDIX A Description of Distresses in Flexible Pavements A-1

154 FLEXIBLE PAVEMENT Distress Type: Description: Raveling Disintegration of the pavement from the surface downward due to the loss of aggregate particles. Raveling may occur as a result of asphalt binder aging, poor mixture quality, segregation, or insufficient compaction. Severity Level: Low-- Very little coarse aggregate has worn away. Loss of fine aggregate. Coarse aggregate exposed. Medium-- High-- Surface has an open texture and is moderately rough with considerable loss of fine aggregate and some coarse aggregate removed. Most of the surface aggregate has worn away or become dislodged. Surface is severely rough and pitted and may be completely removed in places. Extent Level: Occasional-- Less than 20 percent of the surface area is raveling. Frequent-- Extensive-- Between 20 and 50 percent of the surface area is raveling. More than 50 percent of the surface area is raveling. A-2

155 Photo A-1. Raveling in Flexible Pavement, Medium Severity Photo A-2. Raveling in Flexible Pavement, High Severity A-3

156 FLEXIBLE PAVEMENT Distress Type: Description: Severity Level: Bleeding Bleeding or flushing is the presence of free asphalt binder on the pavement surface. Bleeding is caused by an excess amount of bituminous binder in the mixture and/or low air void content. Only 2 severity levels are defined. Medium-- High-- both coarse aggregate and free bitumen are noticeable at the pavement surface. surface appears black with very little aggregate noticeable. Extent Level: Occasional-- less than 10 percent of the length exhibits bleeding. Frequent-- Extensive-- between 10 and 30 percent of the length is bleeding. bleeding occurs in more than 30 percent of the length. A-4

157 Photo A-3. Bleeding in Flexible Pavement, High Severity Photo A-4. Close-up view of Bleeding, High and Medium Severity High Severity on left show s most aggreg ates covered with asphalt and Medium Severity on right show s less aggregates covered w ith aspha lt A-5

158 FLEXIBLE PAVEMENT Distress Type: Description: Patching Patching is either the placing of asphalt concrete on the surface of the existing pavement or the replacement of the existing pavement in small isolated areas. Deductions shall be made for all patches present in the pavement which are the result of deterioration and/or maintenance since the last construction project. Large patched areas [greater than 12.5 m 2 (15 sq. yd.)], such as spot overlays or wedge courses, shall be rated for condition as a part of the existing pavement rather than as patches. Severity Level: Low-- patch size < 0.1 m 2 (1 sq. ft.). Medium-- High-- patch size < 0.8 m 2 (1 sq. yd.). patch size > 0.8 m 2 (1 sq. yd.). Extent Level: Occasional-- < 10 patches/1.6 km (per mile). Frequent-- Extensive patches/1.6 km (per mile). > 20 patches/1.6 km (per mile). A-6

159 Photo A-5. Patching in Flexible Pavement, High Severity Photo A-6. Patching in Flexible Pavement, High Severity A-7

160 FLEXIBLE PAVEMENT Distress Type: Description: Potholes/Debonding Potholes are bowl-shaped voids or depressions in the pavement surface. Potholes are localized failure areas which are usually caused by weak base or subgrade layers. Loss of surface by debonding is the removal of the asphaltic surface layer from the underlying layer. The problem is most common with thin asphalt surface layers [less than 50 mm (2 inches)] and is caused by freeze-thaw action or poor bonding of the two layers during construction. Severity Level: Use the following table to determine the severity levels: Depth of Debonded Area Debonded Area <0.8 m 2 (1 sq. yd.) Debonded Area >0.8 m 2 (1 sq. yd.) < 25 mm (1") Low Medium > 25 mm (1") Medium High Regardless of depth, potholes less than 150 mm (6 inches) in diameter shall be considered to be of low severity. Extent Level: Occasional-- < 5 potholes/1.6 km (per mile). Frequent-- Extensive potholes/1.6 km (per mile). > 10 potholes/1.6 km (per mile). A-8

161 Photo A-7. Pothole in Flexible Pavement, Medium Severity Photo A-8. Debonding in Flexible Pavement, Medium Severity A-9

162 FLEXIBLE PAVEMENT Distress Type: Description: Severity Level: Crack Sealing Deficiency Crack sealing deficiency is crack sealing which is no longer effective in preventing intrusion of water or cracks which have never been sealed. Severity levels are not considered. Extent Level: Occasional-- less than 20 percent of the cracks along the pavement section are not effectively sealed. Frequent Extensive-- between 20 and 50 percent of the cracks along the pavement section are not effectively sealed. more than 50 percent of the cracks along the pavement section are not effectively sealed. A-10

163 Photo A-9. Crack Sealing Deficiency in Flexible Pavement, Unsealed Cracks Photo A-10. Crack sealing Deficiency in Flexible Pavement, Cracks not sealed properly A-11

164 FLEXIBLE PAVEMENT Distress Type: Description: Severity Level: Rutting Ruts are vertical deformations in the pavement surface along the wheel tracks. In severe cases pavement uplift may occur along the sides of the rut, but in most instances only a depression is noticeable. Rutting is caused by consolidation or lateral movement of any or all pavement layers, including subgrade, under traffic. Rutting severity is based upon rut depth, as approximated visually. Low-- Medium-- High-- barely noticeable, depth less than 6 mm (1/4 inch). readily noticeable, depth more than 6 mm (1/4 inch), less than 25 mm (1 inch). definite effect upon vehicle control, depth greater than 25 mm (1 inch). Extent Level: Occasional-- less than 20 percent of the section length is rutted. Frequent-- Extensive-- between 20 and 50 percent of the section length is rutted. more than 50 percent of the section length is rutted. A-12

165 Photo A-11. Rutting in Flexible Pavement, Medium Severity Photo A-12. Rutting in Flexible Pavement, High Severity A-13

166 FLEXIBLE PAVEMENT Distress Type: Description: Severity Level: Settlement Settlement is a dip in the longitudinal profile of the pavement surface. Settlement shall be considered a distress when it causes a noticeable effect upon riding quality. Settlement should not be confused with corrugation, which is another type of surface profile deficiency. Severity is based upon the effect of the settlement on vehicle control when traveling along the roadway at 60 km/hour (40 MPH), as discussed in step 1 of the monitoring procedure. Low-- Medium-- High-- noticeable effect upon ride, driver able to maintain vehicle control easily. some discomfort to passengers, driver able to maintain control with slight corrective action. definite effect upon ride quality, noticeable profile dip generally greater than 150 mm (6 inches). Poor ride, corrective action needed. Extent Level: Occasional-- less than 2 settlements/1.6 km (per mile) of roadway. Frequent-- Extensive-- 2 to 4 settlements/1.6 km (per mile) of roadway. more than 4 settlements/1.6 km (per mile) of roadway. A-14

167 Photo A-13. Settlement, Low Severity Photo A-14. Settlement, Medium Severity A-15

168 FLEXIBLE PAVEMENT Distress Type: Description: Corrugations Corrugations are a series of transverse ridges and valleys (or ripples) occurring at regular intervals along the pavement. Unstable bituminous mixture or poor base quality are associated with this distress. Severity Level: Low-- noticeable effect upon ride, but no significant reduction in comfort. Medium-- High-- moderate ride discomfort is noticeable, driver able to maintain vehicle control easily. vehicle vibration is severe, speed reduction is necessary for comfort and to maintain vehicle control. Extent Level: Occasional-- less than 10 percent of the section length is affected by this distress. Frequent-- Extensive-- between 10 and 30 percent of the section length is affected by this distress. greater than 30 percent of the section length is affected by this distress. A-16

169 Photo A-15. Corrugations in Flexible Pavement, Medium Severity A-17

170 FLEXIBLE PAVEMENT Distress Type: Description: Severity Level: Wheel Track Cracking Cracks located within or near the wheel tracks. For evaluation purposes each wheel track shall be considered 1 m (3 feet) in width. Wheel track cracking usually starts as intermittent, single longitudinal cracks progressing to multiple longitudinal cracking, and eventually interconnected or alligator cracking. Wheel track cracking usually results from fatigue failure of the asphaltic layer. Severity is based upon both crack width and multiplicity of the cracking. Both criteria must be satisfied when assigning severity level. Low-- Medium-- High-- single or intermittent multiple cracking with average crack width less than 6 mm (1/4 inch). single or multiple cracking (may also include regions of intermittent alligator cracking) with average crack width greater than 6 mm (1/4 inch) with little spalling or loose pieces. multiple cracking with extensive alligator cracking. Spalling is fairly common, with average crack width greater than 6 mm (1/4 inch), and some alligator blocks are easily removed. Extent Level: Extent is based upon percentage of the wheel track length within the section which exhibits cracking. Occasional-- Frequent-- Extensive-- less than 20 percent. between 20 and 50 percent. more than 50 percent. A-18

171 Photo A-16. Wheel Track Cracking in Flexible Pavement, Med. Severity Photo A-17. Wheel Track Cracking in Flexible Pavement, High Severity A-19

172 FLEXIBLE PAVEMENT Distress Type: Description: Block and Transverse Cracking Block cracks are interconnected cracks which divide the pavement into large rectangular pieces or blocks. Block size may range from 1 m by 1 m (3 ft. by 3 ft.) upwards to 3 m by 3 m (10 ft. by 10 ft.). Transverse cracking is cracks at approximately right angles to the pavement centerline. The occurrence of both block and/or transverse cracking is usually related to thermal shrinkage of the asphalt binder. Binder age hardening is also related to formation of these crack types. Severity Level: Low-- average crack width less than 6 mm (1/4 inch) with no spalling or distortion along crack edges. Medium-- average crack opened or spalled to a width between 6 mm to 25 mm (1/4 to 1 inch) along at least half its length. High-- average crack opened or spalled to a width greater than 25 mm (1 inch) along at least half its length. Extent Level: Occasional-- less than 20 percent of the section length is affected by this distress. Frequent-- Extensive-- between 20 and 50 percent of this section length is affected by this distress. greater than 50 percent of the section length is affected by this distress. A-20

173 Photo A-18. Block and Transverse Cracking in Flexible Pavement, Medium Severity Photo A-19. Block and Transverse Cracking in Flexible Pavement, High Severity A-21

174 FLEXIBLE PAVEMENT Distress Type: Description: Longitudinal Joint Cracking Deterioration or cracking of the longitudinal joints formed by separate passes of an asphalt paver, including shoulders and widening. Poor compaction along the longitudinal joint often results in the disintegration of material along the joint and may be accompanied by single or multiple cracking. Severity Level: Low-- single longitudinal crack with width less than 6 mm (1/4") and no spalling. Medium-- High-- single or multiple cracking 6 mm - 25 mm (1/4"-1") with some spalling. multiple cracking > 25 mm (1") wide with much spalling. Extent Level: Occasional-- less than 20%. Frequent-- between 20 and 50%. Extensive-- more than 50%. A-22

175 Photo A-20. Longitudinal Joint Cracking in Flexible Pavement, Medium Severity Photo A-21. Longitudinal Joint Cracking in Flexible Pavement, High Severity A-23

176 FLEXIBLE PAVEMENT Distress Type: Description: Edge Cracking Edge cracks are longitudinal or crescent shaped cracks usually within 0.3 m (1 foot) of the pavement edge line. Severity Level: Low-- tight cracks, width less than 6 mm (1/4 inch) with no break up or spalling. Medium-- High-- crack width greater than 6 mm (1/4 inch) with some spalling. multiple cracking with moderate spalling and average crack width greater than 6 mm (1/4 inch). Extent Level: Occasional-- cracking occurs along less than 20 percent of the pavement edge within the section. Frequent-- Extensive-- cracking occurs along 20 to 50 percent of the pavement edge within the section. cracking occurs along more than 50 percent of the pavement edge within the section. A-24

177 Photo A-22. Edge Cracking in Flexible Pavement, Medium Severity Photo A-23. Edge Cracking in Flexible Pavement, High Severity A-25

178 FLEXIBLE PAVEMENT Distress Type: Random Cracking Description: Random cracks are those cracks which are not categorized as one of the 4 previous types of cracks. For example, cracks which meander across or along the pavement would be classified as random cracks. Severity Level: Low-- average crack width less than 6 mm (1/4 inch), no spalling. Medium-- High-- average crack opened or spalled to a width between 6 mm to 25 mm (1/4 to 1 inch) along at least half of its length. average crack opened or spalled to a width greater than 25mm (1 inch) along at least half of its length. Extent Level: Occasional-- random cracks occur along less than 20 percent of the section. Frequent-- Extensive-- random cracks occur along 20 to 50 percent of the section. random cracks occur along more than 50 percent of the section. A-26

179 Photo A-24. Random Cracking in Flexible Pavement, Medium Severity A-27

180 APPENDIX B Description of Distresses in Composite Pavements [Composite Pavements have rigid bases (concrete or brick) and asphaltic surfaces] B-1

181 COMPOSITE PAVEMENT Distress Type: Description: Raveling Disintegration of the pavement from the surface downward due to the loss of aggregate particles. Raveling may occur as a result of asphalt binder aging, poor mixture quality segregation, or insufficient compaction. Severity Level: Low-- very little coarse aggregate has worn away. Loss of fine aggregate. Coarse aggregate exposed. Medium-- High-- surface has an open texture and is moderately rough with considerable loss of fine aggregate and some coarse aggregate removed. most of the surface aggregate has worn away or become dislodged. Surface is severely rough and pitted and may be completely removed in places. Extent Level: Occasional-- less than 20 percent of the surface area is raveling. Frequent-- Extensive-- between 20 and 50 percent of the surface area is raveling. more than 50 percent of the surface area is raveling. B-2

182 Photo B-1. Raveling in Composite Pavement, Medium Severity Photo B-2. Raveling in Composite Pavement, High Severity B-3

183 COMPOSITE PAVEMENT Distress Type: Description: Severity Level: Bleeding Bleeding or flushing is the presence of free asphalt binder on the pavement surface. Bleeding is caused by an excess amount of bituminous binder in the mixture and/or low air void content. Only 2 severity levels are defined. Medium-- High-- both coarse aggregate and free bitumen are noticeable at the pavement surface. surface appears black with very little aggregate noticeable. Extent Level: Occasional-- less than 10 percent of the length exhibits bleeding. Frequent-- Extensive-- between 10 and 30 percent of the length is bleeding. bleeding occurs in more than 30 percent of the length. B-4

184 Photo B-3. Bleeding, High Severity Photo B-4. Close-up view of Bleeding, High and Medium Severity High Severity on left shows most aggregates covered w ith asphalt and Medium Severity on right shows less aggregates covered with asphalt B-5

185 COMPOSITE PAVEMENT Distress Type: Description: Patching Patching is either the placing of asphalt concrete on the surface of the existing pavement or the replacement of the existing pavement in small isolated areas. Deductions shall be made for all patches present in the pavement which are the result of deterioration and/or maintenance since the last construction project. Large patched areas [greater than 12.5 m 2 (15 S.Y.)], such as spot overlays or wedge courses, shall be rated for condition as a part of the existing pavement rather than as patches. Severity Level: Low-- patch size < 0.1 m 2 (1 sq. ft.). Medium-- High-- patch size < 0.8 m 2 (1 sq. yd.). patch size > 0.8 m 2 (1 sq. yd.). Extent Level: Occasional-- < 10 patches/1.6 km (per mile). Frequent-- Extensive patches/1.6 km ((per mile). > 20 patches/1.6 km ((per mile). B-6

186 Photo B-5. Patching in Composite Pavement, Medium Severity Photo B-6. Patching in Composite Pavement, High Severity B-7

187 COMPOSITE PAVEMENT Distress Type: Description: Severity Level: Surface Disintegration or Debonding Loss of surface by debonding is the removal of the asphaltic surface layer from the underlying layer. The problem is most common with thin asphalt surface layers [less than 50 mm (2 inches)] and is caused by freeze-thaw action or poor bonding of the two layers during construction. Use the following table: Depth of Debonded Area Debonded Area <0.8 m 2 (1 sq. yd.) Debonded Area >0.8 m 2 (1 sq. yd.) < 25 mm (1") Low Medium > 25 mm (1") Medium High Extent Level: Occasional-- <5 debonded areas per 1.6 km (per mile). Frequent-- Extensive debonded areas per 1.6 km (per mile). >10 debonded areas per 1.6 km (per mile). B-8

188 Photo B-7. Surface Disintegration in Composite Pavement Photo B-8. Debonding in Composite Pavement, Medium Severity B-9

189 COMPOSITE PAVEMENT Distress Type: Description: Severity Level: Rutting Ruts are vertical deformations in the pavement surface along the wheel tracks. In severe cases pavement uplift may occur along the sides of the rut, but in most instances only a depression is noticeable. Rutting is caused by consolidation or lateral movement of any or all pavement layers, including subgrade, under traffic. Rutting severity is based upon rut depth, as approximated visually. Low-- Medium-- High-- barely noticeable, depth less than 6 mm (1/4 inch). readily noticeable, depth more than 6 mm (1/4 inch), less than 25 mm (1 inch). definite effect upon vehicle control, depth greater than 25 mm (1 inch). Extent Level: Occasional-- less than 20 percent of the section length is rutted. Frequent-- Extensive-- between 20 and 50 percent of the section length is rutted. more than 50 percent of the section length is rutted. B-10

190 Photo B-9. Rutting, Medium Severity Photo B-10. Rutting, High Severity B-11

191 COMPOSITE PAVEMENT Distress Type: Description: Corrugations Corrugations are a series of transverse ridges and valleys (or ripples) occurring at regular intervals along the pavement. Unstable bituminous mixture is associated with this distress. Severity Level: Low-- noticeable effect upon ride, but no significant reduction in comfort. Medium-- High-- moderate ride discomfort is noticeable, driver able to maintain vehicle control easily. vehicle vibration is severe, speed reduction is necessary for comfort and to maintain vehicle control. Extent Level: Occasional-- less than 10 percent of the section length is affected by this distress. Frequent-- Extensive-- between 10 and 30 percent of the section length is affected by this distress. greater than 30 percent of the section length is affected by this distress. B-12

192 Photo not available See Photo A-15 for similar distress in Flexible Pavement Photo B-10a. Corrugations in Composite Pavement B-13

193 COMPOSITE PAVEMENT Distress Type: Description: Severity Level: Pumping Pumping is the ejection of fine soil particles through pavement cracks, joints, or along pavement edges. Pumping can be identified by the presence of surface staining and base or subgrade material near joints or cracks. Shoulder disintegration at the pavement edge is often an indicator of pumping beneath the slab. Severity is based upon the rater's degree of certainty that pumping is occurring as indicated by visual evidence. L & M-- High-- Some staining of the surface around cracks or joints is noted. Rater is quite certain that pumping exists. Clear evidence that pumping exists. Excessive staining, medium severity or greater, faulting, corner breaks or punchouts. Rater is quite certain that pumping exists. Extent Level: Occasional-- Less than 10 of the joints and cracks exhibit pumping. Frequent-- Extensive-- 10 to 25 percent of the joints and cracks exhibit pumping. More than 25 percent of the joints and cracks exhibit pumping. B-14

194 Photo B-11. Pumping in Composite Pavement, Medium Severity Photo B-12. Pumping in Composite Pavement, High Severity B-15

195 COMPOSITE PAVEMENT Distress Type: Description: Shattered Slab Shattered slab is the breakup of the underlying rigid base made evident by surface reflection cracking and/or distortion. Reflection cracks in the asphaltic layer forming rectangular areas less than 1.5 m by 1.5 m (5 ft. by 5 ft.) may indicate that the underlying slab is broken up. Diagonal reflection cracks at transverse joints are indicative of corner breaks in the rigid base. Progressive deterioration will include distortion and faulting of the shattered area. This distress is caused by poor base support or fatigue of the concrete layer. Severity Level: Low-- cracks defining the shattered area are tight [less than 3mm (1/8 inch in width)] with little or no spalling. There is no faulting of the shattered area. Medium-- High-- crack width greater than 3 mm (1/8 inch) with some spalling. Moderate distortion which does effect ride quality somewhat. severe distortion and poor ride quality over the shattered area. Crack pattern indicates break up of the slab into small pieces [less than 0.8 m 2 (1 yd 2 )]. Extent Level: Occasional-- less than 2 shattered slab areas/1.6 km (per mile) of section length. Frequent-- Extensive-- between 2 and 5 shattered slab areas/1.6 km (per mile) of section length. more than 5 shattered slab areas/1.6 km (per mile) of section length. B-16

196 Photo B-13. Shattered Slab of Composite Pavement, High Severity B-17

197 COMPOSITE PAVEMENT Distress Type: Description: Severity Level: Settlement Settlement is a dip in the longitudinal profile of the pavement surface. Settlement shall be considered a distress when it causes a noticeable effect upon riding quality. Settlement should not be confused with corrugation, which is another type of surface profile deficiency. Severity is based upon the effect of the settlement on vehicle control when traveling along the roadway at 60 km/hour (40 MPH), as discussed in step 1 of the monitoring procedure. Low-- Medium-- High-- noticeable effect upon ride, driver able to maintain vehicle control easily. some discomfort to passengers, driver able to maintain control with slight corrective action. definite effect upon ride quality, noticeable profile dip generally greater than 150 mm (6 inches). Poor ride, corrective action needed. Extent Level: Occasional-- less than 2 settlements/1.6 km (per mile) of roadway. Frequent-- Extensive-- 2 to 4 settlements/1.6 km (per mile) of roadway. more than 4 settlements/1.6 km (per mile) of roadway. B-18

198 Photo B-14. Settlement in Composite Pavement, Medium Severity B-19

199 COMPOSITE PAVEMENT Distress Type: Description: Transverse Cracking A crack or break at approximately right angles to the pavement centerline. For composite pavements where the rigid base layer does not have transverse joints (CRC pavements for instance) all transverse cracking is evaluated regardless of location. For jointed bases, a separate evaluation is made of reflective cracks at 1) the joints; and 2) other (non-joint) transverse cracking. Usually all underlying base cracks and joints are eventually reflected through the flexible surface. Additional transverse surface cracking may result from thermal shrinkage and age hardening of the asphaltic layer. Note 1: A significant amount of joint repair and bituminous overlay of Jointed Concrete (JC) pavement has been completed in Ohio. The repair method usually included removal of original pavement at the joint for ± 1 m (3 feet) in each adjacent slab and replacing it with an asphalt or concrete patch. For projects which contain this type of repair, both transverse joints will be evaluated if visible. Note 2: Crack width is defined as the sum of all cracks if more than one is present at the location of measurement (measured as a continuous length from the beginning of the first crack to the end of the last crack). Severity Level: Unjointed Base or Jointed Base Low-- Medium-- crack width less than 6 mm (1/4 inch) with no spalling or distortion along crack edges. crack opened or spalled to a width between 6 mm and 25 mm (1/4 and 1 inch) over at least one half its length. High-- crack opened or spalled to a width greater than 25 mm (1 inch) over at least one half its length. B-20

200 Photo B-15. Unjointed Base, Transverse Cracking in Composite Pavement, Low Severity Photo B-16. Unjointed Base, Transverse Cracking in Composite Pavement, High Severity B-21

201 COMPOSITE PAVEMENT Extent Level: Jointed Base - Intermediate Transverse Cracking Extent level is based upon average crack spacing (CS) as given by the following formula: CS = L/ (Z + 1) Where: CS = average crack spacing in m (ft.), Z = average number of transverse cracks per panel, and L = transverse joint spacing in m (ft.). (Please Note: average CS is based on Step 2 observations). Occasional-- Frequent-- Extensive-- average transverse crack spacing greater than 4.5 m (15 feet). average spacing 3 to 4.5 m (10 to 15 feet). average crack spacing less than 3 m (10 feet). Extent Level: Unjointed Base Occasional-- average intermediate transverse crack spacing greater than 4.5 m (15 feet). Frequent-- average intermediate transverse crack spacing 3 to 4.5 m (10 to 15 feet). Extensive-- average intermediate transverse crack spacing less than 3 m (10 feet). Extent Level: Jointed Base-Joint Reflection Cracks Extent is based upon the estimated percentage of transverse joint length which has reflected through the asphalt surface. Except for new pavements or overlays the extent will likely be extensive. Occasional-- Frequent-- Extensive-- less than 20 percent. between 20 and 50 percent. more than 50 percent. B-22

202 Photo B- 17. Jointed Base, Reflection Cracking in Composite Pavement, Medium Severity Photo B- 18. Jointed Base, Reflection Cracking in Composite Pavement, High Severity B-23

203 COMPOSITE PAVEMENT Distress Type: Description: Longitudinal Cracking A crack or break approximately parallel to the pavement centerline. Longitudinal joints and pavement edges of underlying rigid base usually reflect through the asphalt surface as a result of thermal movement in the underlying slab. Poor paving lane joint construction can also result in a longitudinal crack. All types of longitudinal cracking (random, centerline, edge, etc.) are included in this distress classification for composite pavements. Note: Crack width is defined as the sum of all cracks if more than one is present at the location of measurement. Low-- Medium-- crack width less than 6 mm (1/4 inch) with no spalling or distortion along crack edges. crack opened or spalled to a width between 6 mm and 25 mm (1/4 and 1 inch) over at least one half its length. High-- crack opened or spalled to a width greater than 25 mm (1 inch) over at least one half its length. Extent Level: Based upon the average linear feet of longitudinal cracking per 30 m (per station of 100 feet length). Occasional-- Frequent-- Extensive-- less than 15 m/30 m (50 feet per station). between 15 and 45 m/30 m (50 and 150 feet per station). more than 45 m/30 m (150 feet per station). Complete reflective longitudinal cracking along the pavement centerline and edge [60 linear m/ 30 m (200 linear feet per station)] is termed extensive. B-24

204 Photo B- 19. Longitudinal Cracking in Composite Pavement, High Severity B-25

205 COMPOSITE PAVEMENT Distress Type: Description: Pressure Damage/Upheaval Upheaval is a bump or hump in the pavement surface at a transverse joint or crack. The upheaval is a result of thermal expansion in the underlying concrete base creating compressive forces. Severity Level: Low-- bump height less than 13 mm (½ inch), barely noticeable effect upon ride. Medium-- High-- bump height 13 to 25 mm (½ to 1 inch) with a readily noticeable effect upon ride quality. bump height greater than 25 mm (1 inch) severely reducing ride quality. Extent Level: Occasional-- upheaval is present along less than 20 percent of the joints. Frequent-- Extensive-- upheaval occurs along 20 to 50 percent of the joints. greater than 50 percent of the joints exhibit upheaval. B-26

206 Photo B- 20. Pressure Damage/Upheaval in Composite Pavement, Medium Severity B-27

207 COMPOSITE PAVEMENT Distress Type: Description: Severity Level: Extent Level: Crack Sealing Deficiency Crack sealing deficiency is crack sealing which is no longer effective in preventing intrusion of water or cracks which have never been sealed. Severity levels are not considered. Extent is based upon the percentage of crack length in the pavement surface which is not effectively sealed. Occasional-- Frequent-- Extensive-- less than 20 percent of the cracks along the pavement section are not effectively sealed. between 20 and 50 percent of the cracks along the pavement section are not effectively sealed. more than 50 percent of the cracks along the pavement section are not effectively sealed. B-28

208 Photo B-21. Crack Sealing Deficiency, Unsealed Cracks Photo B-22. Crack Sealing Deficiency, Cracks not sealed properly B-29

209 APPENDIX C Description of Distresses in Jointed Reinforced Concrete or Jointed Plain Concrete Pavements (JRC/JPC Pavements) C-1

210 JRC/JPC PAVEMENT Distress Type: Description: Surface Deterioration Disintegration or loss of concrete from the surface of the pavement. Includes scaling and abrasion. Scaling is the flaking away of the concrete surface. Abrasion is similar to scaling in that a loss of fine, surface aggregate occurs. Abrasion is usually a result of weathering and traffic wear and is normally confined to the wheel track area. Severity Level: Low-- Aggregate visible. Medium-- High-- Surface has an open texture and is moderately rough with considerable loss of fine aggregate and some coarse aggregate removed. Surface rough or pitted. Extent Level: Occasional-- Less than 20 percent of the surface area. Frequent-- Extensive-- 20 to 50 percent of the surface area. Equal to or greater than 50 percent of the surface area. This level includes continuous distress in both wheel tracks. C-2

211 Photo C-1. Surface Deterioration in Jointed Concrete Pavement, Medium Severity Photo C-2. Surface Deterioration in Jointed Concrete Pavement, High Severity C-3

212 JRC/JPC PAVEMENT Distress Type: Description: Severity Level: Popouts Cone shaped holes in the pavement surface with aggregates at the bottom and unrelated to joint or crack spalling. Aggregate quality is related to this type of distress. Popouts usually range from 25 to 100 mm (1 to 4 inches) in diameter and from 13 to 50 mm (½ to 2 inches) in depth. Severity levels are not considered. Extent Level: Occasional-- Less than 20 percent of the area is affected. Frequent-- Extensive-- 20 to 50 percent of the area is affected. More than 50 percent of the area is affected. C-4

213 Photo C-3. Popout in a Concrete Pavement, Plan and Cross-sectional Views Photo C-4. Popouts in a Jointed Concrete Pavement C-5

214 JRC/JPC PAVEMENT Distress Type: Description: Patching Patching is either the placing of additional material on the surface of the existing pavement or the replacement of existing pavement in isolated areas. Deductions shall be made for all patches present in the pavement which are made with asphalt concrete material and are the result of deterioration and/or maintenance since the last construction project. No deductions shall be made for existing patches which consist of sound concrete. Where deterioration exists with a concrete repair, the deterioration shall be rated as part of the pavement. Multiple patches found along a transverse joint or crack which do not interconnect shall be added together to represent the size of one patch. Multiple patches found along a longitudinal joint or crack which do not interconnect, but are within the same slab, shall be added together to represent the size of one patch. Severity Level: Low-- Patch size <0.1 m 2 (1 sq. ft.), and patches are not deteriorated. Medium-- High-- Patch size < 0.1 m 2 (1 sq. ft.), with deterioration present. Patch size > 0.1 m 2 (1 sq. ft.), regardless of deterioration. Extent Level: Occasional-- <10 patches/1.6 km (per mile). Frequent-- Extensive-- 10 to 20 patches/1.6 km (per mile). >20 patches/1.6 km (per mile). C-6

215 Photo C-5. Patching in Jointed Concrete Pavement, Low Severity Photo C-6. Patching in Jointed Concrete Pavement, High Severity C-7

216 JRC/JPC PAVEMENT Distress Type: Description: Severity Level: Pumping Pumping is the ejection of fine soil particles through pavement cracks, joints, or along pavement edges. Pumping can be identified by the presence of surface staining and base or subgrade material near joints or cracks. Shoulder disintegration at the pavement edge is often an indicator of pumping beneath the slab. Severity is based upon the rater's degree of certainty that pumping is occurring as indicated by visual evidence. L & M-- High-- Some staining of the surface around cracks or joints is noted. Rater is quite certain that pumping exists. Clear evidence that pumping exists. Excessive staining, medium severity or greater, faulting, corner breaks or punchouts. Rater is quite certain that pumping exists. Extent Level: Occasional-- Less than 10 of the joints and cracks exhibit pumping. Frequent-- Extensive-- 10 to 25 percent of the joints and cracks exhibit pumping. More than 25 percent of the joints and cracks exhibit pumping. C-8

217 Photo C-7. Pumping in Jointed Concrete Pavement, High Severity Photo C-8. Pumping in Jointed Concrete Pavement, Low Severity C-9

218 JRC/JPC PAVEMENT Distress Type: Description: Faulting Faulting is the difference in elevation between abutting slabs at transverse joints or cracks. Faulting is usually caused by a pumping action of underlying fine grained materials, settlement of soft subgrade, or from curling or warping of slabs due to temperature and moisture gradients. Note: If transverse cracks are faulted, write the letter "C" on the rating form. If both cracks and joints are faulted, write the letter "B". Otherwise, faulting indicates only joints. Severity Level: Low-- Less than 6 mm (1/4 inch) fault. Medium High-- 6 mm to 13 mm (1/4 to ½ inch) fault. Greater than 13 mm (½ inch) fault. Extent Level: Occasional-- Faulting occurs along less than 20 percent of the joints and cracks. Frequent-- Extensive-- Faulting occurs along 20 to 50 percent of the joints and cracks. More than 50 percent of the joints and cracks are faulted. C-10

219 Photo C-9. Sketch showing Faulting in Jointed Concrete Pavement Photo C-10. Faulting in Jointed Concrete Pavement C-11

220 JRC/JPC PAVEMENT Distress Type: Description: Severity Level: Settlement Settlement is a dip or depression in the longitudinal profile of the pavement surface. Settlement should be considered a distress when it causes a noticeable effect upon riding quality. Severity is based upon the effect of the settlement or waves upon ride quality and vehicle control when traveling along the roadway at 60 km/hour (40 MPH, step 1 of the monitoring procedure). Low-- Medium-- High-- Noticeable effect upon ride, driver able to maintain vehicle control easily. Some discomfort to passengers, driver able to maintain control with slight corrective action. Definite effect upon ride quality. Noticeable profile dips in settlement areas greater than 150 mm (6 inches). Waves cause rocking of vehicle similar to motion created at moderately faulted jointed crack pavements. Extent Level: Occasional-- Less than 2 settlement/1.6 km (per mile) of roadway. Frequent-- Extensive-- 2 to 4 settlement areas/1.6 km (per mile) of roadway. More than 4 settlements/1.6 km (per mile) of roadway. C-12

221 Photo C-11. Settlements in Jointed Concrete Pavement, Medium Severity C-13

222 JRC/JPC PAVEMENT Distress Type: Description: Transverse Joint Spalling Joint spalling is the break up or disintegration of the concrete at longitudinal or transverse pavement joints. A spall normally does not extend vertically through the slab but rather intersects the joint at an angle. Often joint spalling is the result of durability ("D") cracking of the pavement. The rater is asked to indicate on the rating form if the joint spalling is a result of "D" cracking. Durability ("D") cracking is a series of fine crescent-shaped cracks in the concrete surface which usually runs parallel to a joint or major crack and curve across slab corners. Cracking pattern is normally concave in relation to slab corners or joints. D-cracking can eventually lead to disintegration and spalling of the concrete near the joints or corners of the slab. Severity Level: Low-- Spalls less than 100 mm (4 inches) wide, measured to the center of the joint, with loss of material, or spalls with no loss of material and no patching. Medium-- High-- spalls 100 mm to 225 mm (4 to 9 inches) wide, measured to the center of the joint, with loss of material. Spalls greater than 225 mm (9 inches) wide, measured to the center of the joint, with loss of material. Extent Level: Occasional-- Less than 25 percent of the transverse joints are spalled. Frequent-- Extensive-- 25 to 75 percent of the transverse joints are spalled. More than 75 percent of the transverse joints are spalled. C-14

223 Photo C-12. Transverse Joint Spalling in Jointed Concrete Pavement, Low Severity Photo C-13. Transverse Joint Spalling in Jointed Concrete Pavement, High Severity C-15

224 JRC/JPC PAVEMENT Distress Type: Description: Severity Level: Joint Sealant Damage Joint sealant damage is any deterioration of the sealant which permits water or incompressibles to enter the joint. Damage includes disintegration, removal, pull out, hardening or debonding of the joint material from the adjoining slab edge. Severity levels are not considered for this distress. Extent Level: Occasional-- Less than 20 percent of the joints are not effectively sealed. Frequent-- Extensive-- 20 and 50 percent of the joints are not effectively sealed. Greater than 50 percent of the joints are not effectively sealed. C-16

225 Photo C-14. Joint Sealant Damage in Jointed Concrete Pavement Photo C-15. Joint Sealant Damage in Jointed Concrete Pavement C-17

226 JRC/JPC PAVEMENT Distress Type: Description: Severity Level: Extent Level: Pressure Damage Pressure damage may be spalling, crushing, or upheaval at transverse joints or cracks resulting from expansion of the concrete layer. Pressure induced spalling is differentiated from other joint spalling by the shape of the spalled area. Pressure spalls are usually 150 to 300 mm (6 to 12 inches) long measured from the crack or joint and up to 300 mm (12 inches) wide. Separate severity levels for pressure damage spalling are not defined. All pressure damage spalling is considered severe since this distress may be a predictor or more serious pressure distress (blow ups). Extent is based upon the number of transverse joints which exhibit pressure damage spalling. Occasional-- Frequent-- Extensive-- Less than 1/1.6 km (per mile). Between 1 and 3/1.6 km (per mile). More than 3/1.6 km (per mile). C-18

227 Photo C-16. Pressure Damage in Jointed Concrete Pavement Photo C-17. Pressure Damage in Jointed Concrete Pavement C-19

228 JRC/JPC PAVEMENT Distress Type: Description: Transverse Cracking A crack or break at approximately right angles to the pavement centerline. Some transverse cracks (hairline shrinkage cracks) are expected in reinforced concrete pavements which have large transverse joint spacing. Additional transverse cracking could be caused by repeated heavy traffic loading, thermal and moisture gradients and subgrade settlement or consolidation. Severity Level: Low-- Hairline or tight with little crack spalling. Medium-- High-- Crack opened or spalled at the surface to a width of 6 mm to 25 mm (1/4 inch to 1 inch) over a distance equal to at least one-half the crack length. Crack opened or spalled at the surface to a width greater than 25 mm (1 inch) over a distance equal to at least one-half the crack length. Extent Level: Extent level is based upon average crack spacing (CS) between intermediate transverse cracks as given by the following expression: CS = L / ( Z + 1 ) where: CS Z L = average crack spacing, m (ft), = average number of transverse cracks per panel, and = transverse joint spacing, m (ft). Average CS is based upon step 2 observations. Occasional-- Frequent-- Extensive-- CS > 4.5 m (15 ft). 3 m (10 ft) < CS < 4.5 m (15 ft). CS < 3 m (10 ft). C-20

229 Photo C-18. Transverse Cracking in Jointed Concrete Pavement, Low Severity Photo C-19. Transverse Cracking in Jointed Concrete Pavement, High Severity C-21

230 JRC/JPC PAVEMENT Distress Type: Description: Longitudinal Cracking A crack or break approximately parallel to the pavement centerline. This type of cracking is usually associated with subgrade settlement or insufficient bearing support. Severity Level: Low-- Hairline or tight cracks with little crack spalling. Medium-- Crack opened or spall at the surface to a width of 6 mm to 25 mm (1/4 inch to 1 inch) over a distance equal to at least onehalf the crack length. High-- Crack opened or spalled at the surface to a width greater than 25 mm (1 inch) over a distance equal to at least one-half the crack length. Extent Level: Occasional-- Less than 5 percent of the slabs have longitudinal cracking. Frequent-- Extensive-- Between 5 and 20 percent of the slabs have longitudinal cracking. More than 20 percent of the slabs have longitudinal cracking. C-22

231 Photo C-20. Longitudinal Cracking in Jointed Concrete Pavement, Medium Severity Photo C-21. Longitudinal Cracking in Jointed Concrete Pavement, Medium Severity C-23

232 JRC/JPC PAVEMENT Distress Type: Description: Corner Breaks A corner break is a crack that intersects transverse joints or cracks and a longitudinal edge diagonally. The leg size of the triangular break is usually greater than 300 mm (12 inches). Corner breaks can be differentiated from spalling by: (1) corner breaks extend vertically through the entire slab whereas spalls are only partial depth cracks, and (2) the triangle formed by a corner break is usually much larger than that of a spall. Severity Level: Low-- Crack width less than 6 mm (1/4 inch) with no spalling or settlement of the broken area. Medium-- High-- Crack width between 6 mm to 25 mm (1/4 inch to 1 inch) with some spalling and minor settlement of the broken area. Crack width greater than 25 mm (1 inch) and/or much spalling and settlement of the broken area. High severity may also be identified by shattering of the broken area by formation of smaller pieces within the corner break area. Extent Level: Occasional-- Less than 4 corner breaks/1.6 km (per mile). Frequent-- Extensive-- 4 and 10 corner breaks/1.6 km (per mile). More than 10 corner breaks/1.6 km (per mile). C-25

233 Photo C-22. Corner Break in Jointed Concrete Pavement, Medium Severity Photo C-23. Corner Breaks in Jointed Concrete Pavement, High Severity C-26

234 APPENDIX D Description of Distresses in Continuously Reinforced Concrete Pavements (CRCP) D-1

235 Distress Type: Surface Deterioration CRC PAVEMENT Description: Disintegration or loss of concrete from the surface of the pavement. Includes scaling and abrasion. Scaling is the flaking away of the concrete surface. Abrasion is similar to scaling in that a loss of fine, surface aggregate occurs. Abrasion is usually a result of weathering and traffic wear and is normally confined to the wheel track area. Severity Level: Low-- Aggregate visible. Medium-- High-- Surface has an open texture and is moderately rough with considerable loss of fine aggregate and some coarse aggregate removed. Surface rough or pitted. Extent Level: Occasional-- Less than 20 percent of the surface area. Frequent-- Extensive-- 20 to 50 percent of the surface area. Equal to or greater than 50 percent of the surface area. This level includes continuous distress in both wheel tracks. D-2

236 Photo D-1. Surface Deterioration in CRC Pavement, Medium Severity Photo D-2. Surface Deterioration in CRC Pavement, High Severity D-3

237 CRC PAVEMENT Distress Type: Description: Severity Level: Popouts Cone shaped holes in the pavement surface with aggregates at the bottom and unrelated to joint or crack spalling. Aggregate quality is related to this type of distress. Popouts usually range from 25 to 100 mm (1 to 4 inches) in diameter and from 13 to 50 mm (½ to 2 inches) in depth. Severity levels are not considered. Extent Level: Occasional-- Less than 20 percent of the area is affected. Frequent-- Extensive-- 20 to 50 percent of the area is affected. More than 50 percent of the area is affected. D-4

238 Photo D-3. Popout in CRC Pavement, Plan and Cross-section Views Photo D-4. Popouts in CRC Pavement D-5

239 CRC PAVEMENT Distress Type: Description: Patching Patching is either the placing of additional material on the surface of the existing pavement or the replacement of existing pavement in isolated areas. Deductions shall be made for all patches present in the pavement which are made with asphalt concrete material and are the result of deterioration and/or maintenance since the last construction project. No deductions shall be made for existing patches which consist of sound concrete. Where deterioration exists with a concrete repair, the deterioration shall be rated as part of the pavement. Multiple patches found along a transverse joint or crack which do not interconnect shall be added together to represent the size of one patch. Multiple patches found along a longitudinal joint or crack which do not interconnect, but are within the same slab, shall be added together to represent the size of one patch. Severity Level: Low-- Patch size <0.1 m 2 (1 sq. ft.), and patches are not deteriorated. Medium-- High-- Patch size <0.1 m 2 (1 sq. ft.)., with deterioration present. Patch size >0.1 m 2 (1 sq. ft.), regardless of deterioration. Extent Level: Occasional-- <10 patches/1.6 km (per mile). Frequent-- Extensive-- 10 to 20 patches/1.6 km (per mile). >20 patches/1.6 km (per mile). D-6

240 Photo D-5. Patching in CRC Pavement, Low Severity Photo D-6. Patching in CRC Pavement, High Severity D-7

241 CRC PAVEMENT Distress Type: Description: Severity Level: Pumping Pumping is the ejection of fine soil particles through pavement cracks, joints, or along pavement edges. Pumping can be identified by the presence of surface staining and base or subgrade material near joints or cracks. Shoulder disintegration at the pavement edge is often an indicator of pumping beneath the slab. Severity is based upon the rater's degree of certainty that pumping is occurring as indicated by visual evidence. L & M-- High-- Some staining of the surface around cracks or joints is noted. Rater is quite certain that pumping exists. Clear evidence that pumping exists. Excessive staining, medium severity or greater, faulting, corner breaks or punchouts. Rater is quite certain that pumping exists. Extent Level: Occasional-- Less than 10% of the joints and cracks exhibit pumping. Frequent-- Extensive-- 10 to 25% of the joints and cracks exhibit pumping. More than 25% of the joints and cracks exhibit pumping. D-8

242 Photo D-7. Pumping in CRC Pavement, Medium Severity Photo D-8. Pumping, High Severity D-9

243 CRC PAVEMENT Distress Type: Description: Severity Level: Settlement and Waves Because CRC pavements have short transverse crack spacing, these pavements can develop short waves or undulation as a result of poor support conditions, frost heave, or permanent deformation of the subgrade. Settlement is a dip or depression in the longitudinal profile of the pavement surface. Severity is based upon the effect of the settlement or waves upon ride quality and vehicle control when traveling along the roadway at 60 km/hour (40 MPH, (step 1 of the monitoring procedure). Low-- Medium-- High-- Noticeable effect upon ride, driver able to maintain vehicle control easily. Some discomfort to passengers, driver able to maintain control with slight corrective action. Definite effect upon ride quality. Noticeable profile dips in settlement areas greater than 150 mm (6 inches). Waves cause rocking of vehicle similar to motion created at moderately faulted jointed crack pavements. Extent Level: Occasional-- Less than 2 settlements/1.6 km (per mile) of roadway and/or wave along less than 20 percent of the section length. Frequent-- Extensive-- 2 to 4 settlement areas/1.6 km (per mile) of roadway and/or waves along 20 to 50 percent of the section length. more than 4 settlement areas/1.6 km (per mile) of roadway and/or waves along more than 50 percent of the section length. D-10

244 Photo D-9. Settlement in CRC Pavement D-11

245 CRC PAVEMENT Distress Type: Description: Transverse Crack Spacing A crack at approximately right angles to the pavement centerline. Transverse cracking in CRC pavements is normal. The cracking is detrimental if the spacing is less than or greater than that associated with good CRC performance. Optimum CRC transverse crack spacing is about 1.5 m 2.4 m (5 to 8 feet). Severity Level: Low-- Average crack spacing greater than 1 m (3 feet). Medium-- High-- Average crack spacing less than 1 m (3 feet), with few intersecting cracks. Intersecting cracks are transverse cracks which do not cross the entire pavement width but intersect other transverse cracks. Average crack spacing less than 1 m (3 feet), with many intersecting cracks. Extent Level: Extent is based upon the percentage of the section length having an undesirable transverse crack pattern. Occasional-- Frequent-- Extensive-- Less than 20 percent. 20 to 50 percent. Greater than 50 percent. D-12

246 Photo D-10. Transverse Cracks in CRC Pavement, Low Severity Photo D-11. Transverse Cracks in CRC Pavement, Medium Severity D-13

247 CRC PAVEMENT Distress Type: Description: Longitudinal Cracking A crack or break approximately parallel to the pavement centerline. This type of cracking is usually associated with subgrade settlement or insufficient bearing support. Severity Level: Low-- Hairline or tight cracks with little crack spalling. Medium-- High-- Crack opened or spall at the surface to a width of 6 to 25 mm (1/4 inch to 1 inch) over a distance equal to at least one-half the crack length. Crack opened or spalled at the surface to a width greater than 25 mm (1 inch) over a distance equal to at least one-half the crack length. Extent Level: Occasional-- Longitudinal cracking occurs along less than 5 percent of the section length. Frequent-- Extensive-- Longitudinal cracking occurs along from 5 to 15 percent of the section length. Longitudinal cracking occurs along more than 15 percent of the section length. D-14

248 Photo D-12. Longitudinal Cracking in CRC Pavement, Medium Severity Photo D-13. Longitudinal Cracking in CRC Pavement, High Severity D-15

249 CRC PAVEMENT Distress Type: Description: Severity Level: Punchouts or Edge Breaks A punchout or edge break is a cracked rectangular area usually along the outside pavement edge. A punchout requires formation of longitudinal crack (usually within the outer wheel track) which connects transverse cracks of the CRC pavement. The rectangular punchout area thus is defined by 2 transverse cracks, the longitudinal crack and the outside pavement edge. A punchout results from concrete that is over stressed because of short transverse crack spacing or poor support of the CRC pavement. Punchout areas which have been repaired should be evaluated for patching distress. This distress is rated only for Medium and High levels. Medium-- High-- Crack width greater than 6 mm (1/4 inch) with some spalling. Punchout area may be depressed up to 13 mm (½ inch). Punchout area is depressed more than 13 mm (½ inch) and/or is breaking up or shattering. Extent Level: Occasional-- Fewer than 2 punchouts/1.6 m (per mile) of section length. Frequent-- Extensive-- Between 2 and 5 punchouts/1.6 m (per mile) of section length. More than 5 punchouts/1.6 m (per mile) of section length. D-16

250 Photo D-14. Punchouts in CRC Pavement, Medium Severity Photo D-15. Punchouts in CRC Pavement, High Severity D-17

251 CRC PAVEMENT Distress Type: Description: Spalling Spalling in CRC pavements is the break up or disintegration of the concrete at transverse cracks. A spall normally does not extend vertically through the entire concrete layer but intersects the transverse crack at an angle. This distress may be caused by the presence of high percentage of reinforcing steel in the pavement. Severity Level: Low-- < 25 mm (1"), missing pieces. Medium-- High-- Distressed area 25 to 100 mm (1-4 inch) wide with most of the pieces missing. Distressed areas more than 100 mm (4 inch) wide with some or most of the pieces missing. Extent Level: Extent of this distress is based upon the percentage of transverse cracks which have spalled. Occasional-- Frequent-- Extensive-- Less than 20 percent of the cracks. Between 20 and 50 percent of the cracks. More than 50 percent of the cracks. D-18

252 Photo D-16. Spalling in CRC Pavement, Medium Severity Photo D-17. Spalling in CRC Pavement, High Severity D-19

253 CRC PAVEMENT Distress Type: Description: Severity Level: Extent Level: Pressure Damage Pressure damage may be spalling, crushing, or upheaval at transverse joints or cracks resulting from expansion of the concrete layer. Pressure induced spalling is differentiated from other joint spalling by the shape of the spalled area. Pressure spalls are usually 150 to 300 mm (6 to 12 inches) long measured from the crack or joint and up to 300 mm (12 inches) wide. Separate severity levels for pressure damage spalling are not defined. All pressure damage spalling is considered severe since this distress may be a predictor of more serious pressure distress (blow ups). Extent is based upon the number of transverse joints which exhibit pressure damage spalling. Occasional-- Frequent-- Extensive-- Less than 1 joint/1.6 km (per mile). Between 1 and 3 joints/1.6 km (per mile). More than 3 joints/1.6 km (per mile). D-20

254 Photo D-18. An Example of Pressure Damage in Jointed Concrete Pavement. Pressure Damage in CRCP is similar to as shown above. D-21