HOT MIX ASPHALT - Troubleshooting and Process Control (HMA-TPC)

Transcription

1 HOT MIX ASPHALT - Troubleshooting and Process Control (HMA-TPC) For Mix Design # 123-Z-2012 Gmm Gmb Density Air Voids VMA %A.C. INCREASES --- %A.C. DECREASES --- GRADATION FINE --- GRADATION COARSE --- P#200 (75 m) INCREASES --- P#200 (75 m) DECREASES --- Note: proportionality rules are theoretically-based mathematical concepts that hold true for a number of mixture volumetric properties. However, these concepts may vary between mix designs. HIGHWAY TECHNICIAN CERTIFICATION PROGRAM University of Wisconsin-Platteville 049 Ottensman Hall 1 University Plaza Platteville, WI Office Phone; Fax:

2 PREFACE The Hot Mix Asphalt Troubleshooting & Process Control training course was developed as a team effort with cooperation from the Wisconsin Department of Transportation and the asphalt highway construction industries. The following committee members and class instructors have been very instrumental, along with many others, as contributors in developing the content of this course manual: Judie Ryan, Consultant Brian Pitlik, Pitlik & Wick, Inc. Lance Mangles, Pitlik & Wick, Inc. Joe Kyle, American Asphalt of WI. Karl Runstrom, Northeast Asphalt John Jorgenson, Mathy Construction Pat Shuda, WisDOT North Central Region Ray Spellman, UW-Platteville WisDOT Technical Assistance Hotline Representative Barry Paye, WisDOT Bureau of Technical Services, WisDOT Technical Hot-Line Representatives SW Matthew.Smith@dot.wi.gov Madison Matt Smith SW Steven.Ames@dot.wi.gov LaCrosse Steve Ames SE Waukesha Jim Boggs NE Green Bay Brian Jandrin NC Patrick.Shuda@dot.wi.gov WI Rapids Patrick Shuda NC Dean.Gritzmacher@dot.wi.gov Rhinelander Dean Gritzmacher NW Amber.Beaver@dot.wi.gov Eau Claire Amber Beaver NW Thomas.Rossmann@dot.wi.gov Superior Tom Rossman BTS Jeffrey.Anderson@dot.wi.gov Madison Jeffrey Anderson

3 TABLE OF CONTENTS Intro - 2 Course Overview Introduction Course Prerequisites Certification Requirements Recertification Requirements Revocation/Suspension of Certification Highway Technician Certification Program Goal Course Syllabus Topic A Course Introduction Welcome... A-1 Introduction of Course Participants... A-1 What Do You Expect From This Training Course?... A-1 Duties and Responsibilities of a HMA-TPC... A-1 Comprehensive Survey... A-2 Acronyms for Asphalt... A-3 Topic B Quality Management Program What is Quality Management... B-1 WisDOT Quality Management Program, Standard Specification Section 460 WisDOT Construction and Materials Manual Section 8-36 Exercises... B-2 Topic C Overview of Mix Design Purpose of Asphalt Mix Design... C-1 Laboratory Design versus Field Production... C-1 Asphaltic Mix Design Report and Job Mix Formula... C-1 Asphalt Mix Design Report... C-4 Maximum Density Line Relationships... C-5 VMA, Voids in the Mineral Aggregate... C-6 Test Property Curves for HMA... C-9 Selection of Percent Asphalt Content from Air Voids Data... C-10 Selection of Percent Asphalt Content Satisfying All Design Criteria... C-10 Dust to Binder Ratio... C-11 Increase of P-200 During Mix Design... C-11 Asphaltic Mix Design Review Process... C-12 Mix Design Exercises... C-13 Topic D Aggregate Blending

4 Intro - 3 Aggregate Blending... D-1 Federal Highway Administration (FHWA) 0.45 Power Chart... D-6 Maximum Density Line... D-6 Aggregate Blending Exercises... D-8 Topic E Quality Control Organizational Plan Quality Control Organizational Plan... E-1 Request for Job Mix Formula Change... E-6 Job Mix Formula Adjustment... E-6 Quality Management Process Flow... E-8 Asphaltic Mixture Sampling Plan... E-8 Random Sampling Exercises... E-9 Topic F Data Entry Atwood Systems... F-1 WisDOT Software... F-2 Topic G Asphalt Mixing Plants Batch Mix Facility Components... G-2 Drum Mix Facility Components... G-2 Exercises on Asphalt Mixing Facilities... G-3 Topic H Process Control of Asphaltic Mixtures Process Control of Asphaltic Mixtures... H-1 Aggregate Gradation... H-1 Stockpile versus Cold Feed Gradation Data... H-1 Cold Feed versus Extraction Gradation Data... H-1 Asphalt Content... H-2 Nuclear Gauge... H-2 Significance of Gradation and Asphalt Content... H-3 Sources of Possible Problems in a B.M.F.... H-6 Sources of Possible Problems in a Drum Plant... H-7 Problems Associated with Aggregate... H-9 Factors or Causes Attributed to Aggregate Problems... H-10 Factors Attributed to Production (Plant) Problems... H-10 Causes Attributed to Production (Plant) Problems... H-11 Factors Attributed to Equipment-Related Problems... H-12

5 Intro - 4 Aggregate Diagnostic Problems... H-13 Gradation Variability... H-14 Mixture Diagnostic Problems... H-15 Change in Maximum Specific Gravity, Gmb Indicates... H-15 Process Control Problem Solving Using a Flow Chart... H-16 Exercises on Asphalt Mixing Facility... H-17 Topic I Troubleshooting Mixtures, Sampling and Testing, and Asphalt Problems Sampling and Testing Errors in Aggregate... I-1 Sampling and Testing Problems Associated With Asphaltic Mixtures... I-2 Factors Affecting Maximum Specific Gravity, Gmm... I-3 Exceeding Allowable Differences on Test Results... I-3 Calculations Using Theoretical Maximum Specific Gravity, Gmm... I-4 Topic J Process Control Relationships Control Charts... J-1 Gradation Master Band... J-1 Documentation... J-2 Relationships of Asphaltic Mixture Properties... J-2 Asphaltic Mixture Property General Guidelines... J-4 Predetermined Proportionality Rules for Asphalt Mixture Properties... J-4 Process Control Relationship Exercises... J-5 to J-15 Topic K Process Control Relationship Problems APPENDIX Appendix 1: Answers to Student Problems -- WisDOT Test Method No Appendix 2: Mechanics of Mix Design & Recycling Appendix 3: QMP Award, Corrections, Course Evaluation Appendix 4: WisDOT SS 460, General Requirements for Asphaltic Pavements

6 Course Overview Intro - 5 Introduction The Highway Technician Certification Program (HTCP) welcomes you to the Certified Asphaltic Technician TPC course. This course requires 20 hours of classroom attendance. The course content will cover Wisconsin Department of Transportation (WisDOT) standard part 4 specifications related to asphaltic pavements, aggregate blending, guide for quality management program activities, hot mix asphalt design methodology; types of asphalt plants, process control/troubleshooting techniques, and statistical quality control. Course Prerequisites Student candidates must have successfully completed one construction season of field experience in materials testing after certification as a Certified Asphaltic Technician IPT (including all prerequisites). A person may earn 2.0 continuing education units (CEUs) upon successful completion of this course. Certification Requirements The written examination will be limited to a maximum duration of two (2) hours. The written examination will be open book and open notes and will consist of true/false questions, multiple choice questions and essay problems. A student will be required to obtain a passing score of 70 percent to be certified as an Asphaltic Technician TPC. Recertification Requirements Recertification is mandatory every three (3) years. The HTCP will send a recertification notice to each certified technician and the firm or agency prior to the expiration date of the highest certification level(s) of certification obtained. The certified technician must apply for recertification before the expiration date of the highest level(s) obtained. Each certified technician is responsible for obtaining his/her recertification. Revocation/Suspension of Certification Upon written request from any individual, firm, agency, or contractor associated with the HTCP, the HTCP director will provide technical assistance in investigating any alleged report(s) of either certified technician incompetence or act(s) of malfeasance. The HTCP director will then notify WisDOT of the report findings concerning certified technician incompetence or misconduct. Highway Technician Certification Program Goal The principle goal of the Highway Technician Certification Program (HTCP) is to certify that individuals have demonstrated the abilities to engage in quality control/quality assurance activities in highway work contracted by the Wisconsin Department of Transportation (WisDOT).

7 Intro - 6 Course Syllabus 8:00-8:15 COURSE OVERVIEW Day 1 8:15-9:00 TOPIC A: Course Introduction 9:00-11:00 TOPIC B: Specifications a. WisDOT QC/QA 11:00 - NOON TOPIC C: Overview of Mix Design a. Method b. Report. NOON - 1:00 LUNCH BREAK 1:00-1:30 TOPIC D: Aggregate Blending 1:30-2:30 TOPIC E: Q.M.P. Guide/Procedures/Verification Guidelines Outline 2:00-3:30 TOPIC F: Q.M.P. Activities 3:30-4:30 TOPIC G: Plant Operation-Reference part II in U.S. Army Corps Handbook Hot-Mix Asphalt Paving a. Batch b. Drum 4:30-5:00 TOPIC H: Process Control - Mix Design Property Problems (What) a. Gradation b. Voids c. VMA d. % AC Day 2 8:00-9:30 TOPIC I: Process Control - Problem Causes (Why) a. Materials b. Manufacturing Process c. Test Methods 9:30 - NOON TOPIC J: Process Control - Problem Solutions (How) a. Materials (Blending/Handling) b. Manufacturing Process (Plant Calibration Operation) c. Test Methods (Calibration/Calculations) NOON - 1:00 LUNCH BREAK 2:30-5:00 TOPIC K: Asphaltic Mix Design Troubleshooting Exercises Day 3 8:00-9:00 TOPIC K: Asphaltic Mix Design Troubleshooting Exercises (Continued) 9:00-10:00 TOPIC L: Data Entry and General Review 10:00 - NOON Written Examination and Course Evaluation ADJOURN

8 TOPIC A: Course Introduction

9 TOPIC A: Introduction Page A-1 WELCOME! The HTCP welcomes you to the Hot Mix Asphalt Troubleshooting & Process Control training course. First of all, please make sure you have satisfied all course prerequisites before completing this course. Certification will be granted only if you successfully complete this course and have satisfied all course prerequisites. Introduction of Course Participants As a Hot Mix Asphalt IPT Process Control Technician, you have gained valuable work experience by testing the overall quality of asphalt paving mixtures. The intent of this course is for the participants to have an opportunity to gain a wealth of knowledge by sharing their work experiences with others. At this time, you will be asked to introduce yourself, company name, years of service to the asphalt industry, and your present occupational duty. What Do You Expect From This Training Course? This is your opportunity, as a course participant, to ask the course instructor to cover any other topics related to asphalt paving mixtures. Please list and identify any additional related asphalt paving mixture topics below: Duties and Responsibilities of a Hot Mix Asphalt Troubleshooting & Process Control Technician: The duties and responsibilities of a Hot Mix Asphalt Troubleshooting & Process Control Technician involve: Knowing which samples and tests are required, being able to perform them, and computing the test data results Knowing who is responsible for sampling and testing asphalt

10 TOPIC A: Introduction Page A-2 Knowing the proper frequency of sampling and testing and being able to sample and test as required by specification Knowing the mathematical random number process for selecting a sample location and when it is required by specification Knowing the specification requirements and evaluating test results in relation to these specifications Being able to properly prepare, maintain and analyze control charts and controlling the production process by making troubleshooting adjustments that comply to the asphaltic mixture specifications. Being able to maintain records in an organized manner and documenting sampling and testing performed and actions taken as a result of sampling and testing required by specification

11 TOPIC A: Introduction Page A-3 Acronyms for Asphalt Acronyms Pertaining to Hot-Mix Asphalt AASHTO AC AMRL ASTM CA CAA ESAL FAA G b G mb G mm G sa G sb G se HMA JMF MEPDG NAPA NCAT NCHRP NMAS P b P be P ba P s QC QMP QV RAM RAP RAS SGC SHA SHRP SMA SSD TSR VFA VFB VMA VTM or VA WAPA WHRP WMA American Association of State Highway & Transportation Officials Asphalt Cement (Liquid Binder) AASHTO Materials Research Laboratory American Society for Testing & Materials Contractor Assurance Coarse Aggregate Angularity Equivalent Single Axle Load Fine Aggregate Angularity Specific Gravity of the Binder Bulk Specific Gravity (Asphaltic Mixture) Maximum Specific Gravity of the Mixture Apparent Specific Gravity (Aggregate) Bulk Specific Gravity (Aggregate) Effective Specific Gravity (Aggregate) Hot-Mix Asphalt Job Mix Formula Mechanistic and Empirical Pavement Design Guide National Asphalt Pavement Association National Center for Asphalt Technology National Cooperative Highway Research Program Nominal Maximum Aggregate Size % Binder Effective % Binder % Binder Absorption % Stone Quality Control Quality Management Program Quality Verification Recycled Asphalt Materials Recycled Asphalt Pavement Recycled Asphalt Shingles Superpave (or SHRP) Gyratory Compactor State Highway Agency Strategic Highway Research Program Stone Matrix Asphalt Surface Saturated Dry Tensile Strength Ratio Voids Filled with Asphalt Voids Filled with Binder Voids in Mineral Aggregate Voids in Total Mix (Air Voids) Wisconsin Asphalt Pavement Association Wisconsin Highway Research Program Warm Mix Asphalt

12 TOPIC B: Quality Management Program

13 TOPIC B: Specifications and Construction and Materials Manual Page B-2 What is Quality Management? Wisconsin Department of Transportation (WisDOT) construction projects require compliance with specifications. Different materials require different testing and at varying frequencies. In the past, WisDOT had the responsibility for checking materials compliance with the specifications. Thus, contractors did not always accept responsibility for controlling their own production process. Because of an expanding emphasis on quality, WisDOT has employed a system that relies on contractor Quality Control and Department Product Verification. Within this concept, the contractor is contractually required to perform a uniform and detailed process control called quality control (QC). WisDOT will also test a specified minimum number of samples taken for product quality verification (QV). Both QC and QV personnel will be required to be certified. Occasionally, WisDOT will conduct equipment and process inspections and comparative tests to validate the Quality Management Program. This latter operation is referred to as independent assurance testing. One of the main responsibilities of an HMA-TPC Technician is to know the contract requirements and specifications for each particular job. As an HMA-TPC Technician, you may be administering more than one contract at a time. BE FAMILIAR WITH THE SPECIFIC DETAILS OF EACH CONTRACT!!!

14 460.1 Description Section 460 Hot Mix Asphalt Pavement (1) This section describes HMA mixture design, providing and maintaining a quality management program for HMA mixtures, and constructing HMA pavement. Unless specifically indicated otherwise, references within 460 to HMA also apply to WMA Materials General (1) Furnish a homogeneous mixture of coarse aggregate, fine aggregate, mineral filler if required, SMA stabilizer if required, recycled material if used, warm mix asphalt additive or process if used, and asphaltic material Aggregates General. (1) Provide coarse aggregates from a department-approved source as specified under Obtain the engineer's approval of the aggregates before producing HMA mixtures. (2) Furnish an aggregate blend consisting of hard durable particles containing no more than a combined total of one percent, by weight, of lumps of clay, loam, shale, soft particles, organic matter, adherent coatings, and other deleterious material. Ensure that the aggregate blend conforms to the percent fractured faces and flat & elongated requirements of table If the aggregate blend contains materials from different deposits or sources, ensure that material from each deposit or source has a LA wear percent loss meeting the requirements of table Freeze-Thaw Soundness (1) If the aggregate blend contains materials from different deposits or sources, ensure that material from each deposit or source has a freeze-thaw loss percentage meeting the requirements of table and Aggregate Gradation Master Range Revise table to increase VMA by 0.5% for E-0.3 and E-3 mix designs with 12.5 and 9.5 mm aggregates. This change was implemented in ASP 6 effective with the December 2014 letting. (1) Ensure that the aggregate blend, including recycled material and mineral filler, conforms to the gradation requirements in table The values listed are design limits; production values may exceed those limits. TABLE AGGREGATE GRADATION MASTER RANGE AND VMA REQUIREMENTS PERCENTS PASSING DESIGNATED SIEVES SIEVE NOMINAL SIZE 37.5 mm 25.0 mm 19.0 mm 12.5 mm 9.5 mm SMA 12.5 mm SMA 9.5 mm 50.0-mm mm mm 90 max mm 90 max mm 90 max mm 90 max mm 90 max mm µm % MINIMUM VMA [1] 15.0 [2] Not For Contract Administration [1] [2] 14.5 for E-0.3 and E-3 mixes for E-0.3 and E-3 mixes. (2) Unless the contract designates otherwise, ensure that the nominal size of the aggregate used in the mixture conforms to and the following: PAVEMENT LAYER NOMINAL SIZE Effective with the December 2015 Letting Standard Specifications

15 Lower layer pavement mm Upper layer pavement mm Stone matrix layer pavement mm Asphaltic Binders (1) The department will designate the grade of asphaltic binder in the contract. The contractor may use virgin binder, modified binder, a blend of virgin and recovered binder, or a blend of modified and recovered binder. Ensure that the resultant asphaltic binder conforms to the contract specifications Additives Hydrated Lime Antistripping Agent (1) If used in HMA mixtures, furnish hydrated lime conforming to ASTM C977 and containing no more than 8 percent unhydrated oxides. Percent added is by weight of the total dry aggregate Liquid Antistripping Agent (1) If used in HMA mixtures, add liquid antistripping agent to the asphaltic binder before introducing the binder into the mixture. Provide documentation indicating that addition of liquid antistripping agent will not alter the characteristics of the original asphaltic binder performance grade (PG) Stone Matrix Asphalt Stabilizer (1) Add an organic fiber, an inorganic fiber, a polymer-plastic, a polymer-elastomer, or approved alternate stabilizer to all SMA mixtures. If proposing an alternate, submit the proposed additive system, asphaltic binder, and stabilizer additive, along with samples of the other mixture materials to the department at least 14 days before the project let date. The department will approve or reject that proposed alternate additive system no later than 48 hours before the project let date. (2) Use a single additive system for all SMA pavement in the contract Warm Mix Asphalt Additive or Process (1) Use additives or processes from the department's approved products list. Follow supplier or manufacturer recommendations for additives and processes when producing WMA mixtures Recycled Asphaltic Materials (1) The contractor may use recycled asphaltic materials from FRAP, RAP, and RAS in HMA mixtures. Stockpile recycled materials separately from virgin materials and list each as individual JMF components. (2) Control recycled materials used in HMA by evaluating the percent binder replacement, the ratio of recovered binder to the total binder. Conform to the following: MAXIMUM ALLOWABLE PERCENT BINDER REPLACEMENT RECYCLED ASPHALTIC MATERIAL LOWER LAYERS UPPER LAYER RAS if used alone RAP and FRAP in any combination RAS, RAP, and FRAP in combination[1] [1] When used in combination the RAS component cannot exceed 5 percent of the total weight of the aggregate blend Recovered Asphaltic Binders (1) Establish the percent of recovered asphaltic binder from FRAP, RAP, and RAS for the mixture design according to AASHTO T164 using the appropriate dust correction procedure. If production test results indicate a change in the percent of recovered asphaltic binder, the contractor or the engineer may request a change in the design recovered asphaltic binder. Provide the department with at least 2 recent extraction samples supporting that change. Ensure that those samples were prepared according to CMM 8-65 by a WisDOT qualified laboratory. Not For Contract Administration (2) The contractor may replace virgin binder with recovered binder up to the maximum percentage allowed under without changing the asphaltic binder grade. If using more than the maximum allowed under , furnish test results indicating that the resultant binder meets the grade the contract originally specified HMA Mixture Design (1) For each HMA mixture type used under the contract, develop and submit an asphaltic mixture design according to the department's test method number 1559 as described in CMM 8-66 and conforming to the Effective with the December 2015 Letting Standard Specifications

16 requirements of table and table The values listed are design limits; production values may exceed those limits. The department will review mixture designs and report the results of that review to the designer according to the department's test method number TABLE MIXTURE REQUIREMENTS Mixture type E E - 1 E - 3 E - 10 E - 30 E - 30x SMA ESALs x 10 6 (20 yr design life) < < < < < 30 >= 30 LA Wear (AASHTO T96) 100 revolutions(max % loss) revolutions(max % loss) Soundness (AASHTO T104) (sodium sulfate, max % loss) Freeze/Thaw (AASHTO T103) (specified counties, max % loss) Fractured Faces (ASTM 5821) (one face/2 face, % by count) Flat & Elongated (ASTM D4791) (max %, by weight) Fine Aggregate Angularity (AASHTO T304, method A, min) Sand Equivalency (AASHTO T176, min) Gyratory Compaction / 65 / 75 / / / / /90 5 (5:1 ratio) 5 (5:1 ratio) 5 (5:1 ratio) 5 (5:1 ratio) 5 (5:1 ratio) 5 (5:1 ratio) 20 (3:1ratio) Gyrations for N ini Gyrations for N des Gyrations for N max Air Voids, %V a (%G mm N des ) 4.0 (96.0) 4.0 (96.0) 4.0 (96.0) 4.0 (96.0) 4.0 (96.0) 4.0 (96.0) % G mm N ini <= 91.5 [1] <= 90.5 [1] <= 89.0 [1] <= 89.0 <= 89.0 <= 89.0 % G mm N max <= 98.0 <= 98.0 <= 98.0 <= 98.0 <= 98.0 <= 98.0 Dust to Binder Ratio [2] (% passing 0.075/P be ) Voids filled with Binder (VFB or VFA, %) Tensile Strength Ratio (TSR) (ASTM 4867) 4.0 (96.0) [4] [5] [4] [3] [4] [3] [4] [3] [4] [3] [4] no antistripping additive with antistripping additive Draindown at Production Temperature (%) 0.30 [1] The percent maximum density at initial compaction is only a guideline. Not For Contract Administration [2] For a gradation that passes below the boundaries of the caution zone (ref. AASHTO MP3), the dust to binder ratio [3] limits are For 9.5mm and 12.5 mm nominal maximum size mixtures, the specified VFB range is 70-76%. [4] For 37.5mm nominal maximum size mixes, the specified VFB lower limit is 67%. [5] For 25.0mm nominal maximum size mixes, the specified VFB lower limit is 67%. Effective with the December 2015 Letting Standard Specifications

17 Quality Management Program General (1) Provide and maintain a QC program defined as all activities, including mix design, process control inspection, sampling and testing, and process adjustments related to producing and placing HMA pavement conforming to the specifications. The contractor may also provide an optional CA program. (2) The department will provide product quality verification as follows: 1. By conducting verification testing of independent samples. 2. By periodically observing contractor sampling and testing. 3. By monitoring required control charts exhibiting test results and control parameters. 4. By the engineer directing the contractor to take additional samples at any time during production. (3) Refer to CMM 8-36 for detailed guidance on sampling, testing, and documentation under the QMP Contractor Testing Required Quality Control Program Personnel Requirements (1) Provide HTCP-certified sampling and testing personnel. Provide at least one full-time HMA technician certified at a level appropriate for sampling and production control testing at each plant site furnishing material to the project. Before mixture production begins, provide an organizational chart in the contractor's laboratory. Include the names, telephone numbers, and current certifications of all personnel with QC or CA responsibilities. Keep the chart updated. (2) Ensure that sampling and testing personnel are minimally qualified as follows [1] : - HMA technician certified at a level appropriate for sampling and production control testing. - HMA ACT [2]. [1] After informing the engineer, a non-certified person under the direct observation of a certified HMA technician may sample for a period not to exceed 3 calendar days. [2] A certified HMA technician must coordinate and take responsibility for the work an ACT performs. No more than one ACT can work under a single certified technician. (3) Have a certified HMA technician ensure that all sampling and testing is performed correctly, analyze test results, and post resulting data. (4) Have an HMA technician certified at a level appropriate for process control and troubleshooting or mix design available to make necessary process adjustments Laboratory Requirements (1) Conduct QC testing in a facility conforming to the department's laboratory qualification program. (2) Ensure that the laboratory has at least 320 square feet of workspace and has a telephone for exclusive use by QMP personnel. Ensure that all testing equipment conforms to the equipment specifications applicable to the required testing methods Required Sampling and Testing Contracts with 5000 Tons of Mixture or Greater (1) Furnish and maintain a laboratory at the plant site fully equipped for performing contractor QC testing. Have the laboratory on-site and operational before beginning mixture production. Not For Contract Administration (2) Obtain random samples and perform tests according to CMM Obtain HMA mixture samples from trucks at the plant. Perform tests the same day taking the sample. (3) Retain the split portion of the contractor HMA mixture and blended aggregate samples for 14 calendar days at the laboratory site in a dry, protected area. The engineer may decrease this 14-day retention period. At project completion the contractor may dispose of remaining samples if the engineer approves. (4) Use the test methods identified below, or other methods the engineer approves, to perform the following tests at a frequency greater than or equal to that indicated: Blended aggregate gradations: Drum plants: Effective with the December 2015 Letting Standard Specifications

18 - Field extraction by CMM 8-36 WisDOT Test Method Belt samples, optional for virgin mixtures, obtained from stopped belt or from the belt discharge using an engineer-approved sampling device and performed according to AASHTO T11 and T27. Batch plants: - Field extraction by CMM 8-36 WisDOT Test Method Asphalt content (AC) in percent: AC by calculation. AC by nuclear gauge reading, optional. AC by inventory, optional. Bulk specific gravity of the compacted mixture according to AASHTO T166. Maximum specific gravity according to AASHTO T209. Air voids (V a ) by calculation according to AASHTO T269. VMA by calculation according to AASHTO R35. (5) Test each design mixture at a frequency at or above the following: TOTAL DAILY PLANT PRODUCTION FOR DEPARTMENT CONTRACTS SAMPLES in tons PER DAY [1] 50 to to to to greater than 4200 see footnote [2] [1] Frequencies are for planned production. If production is other than planned, conform to CMM [2] Add a random sample for each additional 1500 tons or fraction of 1500 tons. (6) Also conduct field tensile strength ratio tests according to ASTM D4867 on all mixtures requiring an antistripping additive. Test each full 50,000 ton production increment, or fraction of an increment, after the first 5000 tons of production. Perform required increment testing in the first week of production of that increment. If field tensile strength ratio values are either below the spec limit or less than the mixture design JMF percentage value by 20 or more, notify the engineer. The engineer and contractor will jointly determine a corrective action Contracts with Less Than 5000 Tons of Mixture (1) Conform to modified as follows: - The contractor may conduct QC tests in an off-site laboratory. - No field tensile strength ratio testing is required Contracts with Less Than 500 Tons of Mixture (1) The engineer may waive QC testing on contracts with less than 500 tons of mixture. If testing is waived, acceptance will be by visual inspection unless defined otherwise by contract change order. (2) If HMA density testing is waived under , QC testing is also waived Temporary Pavements (1) The engineer may waive all testing for temporary pavements, defined for this purpose as pavements that will be placed and removed before contract completion Documentation Records (1) Document all observations, inspection records, mixture adjustments, and test results daily. Note observations and inspection records in a permanent field record as they occur. Record all process adjustments and JMF changes. Submit copies of the running average calculation sheets for blended Not For Contract Administration Effective with the December 2015 Letting Standard Specifications

19 aggregate, mixture properties, and asphalt content along with mixture adjustment records to the engineer each day. Submit testing records and control charts to the engineer in a neat and orderly manner within 10 days after paving is completed. (2) Continue charts, records, and testing frequencies, for a mixture produced at one plant site, from contract to contract Control Charts (1) Maintain standardized control charts at the laboratory. Record contractor test results on the charts the same day as testing. Post CA test results on the charts as data becomes available. Record data on the standardized control charts as follows: - Blended aggregate gradation tests in percent passing. Of the following, plot those sieves the design specifications require: 37.5-mm, 25.0-mm, 19.0-mm, 12.5-mm, 9.5-mm, 2.36-mm, and 75-µm. - Asphalt material content in percent. - Air voids in percent. - VMA in percent. (2) Plot both the individual test point and the running average of the last 4 data points on each chart. Show QC data in black with the running average in red and CA data in blue. Draw the warning limits with a dashed green line and the JMF limits with a dashed red line. The contractor may use computer generated black-and-white printouts with a legend that clearly identifies the specified color coded components Control Limits (1) Conform to the following control limits for the JMF and warning limits based on a running average of the last 4 data points: ITEM JMF LIMITS WARNING LIMITS Percent passing given sieve: 37.5-mm +/ / mm +/ / mm +/ / mm +/ / mm +/ / mm +/ / µm +/ /- 1.5 Asphaltic content in percent Air voids in percent +/ /- 1.0 VMA in percent [1] [1] VMA limits based on minimum requirement for mix design nominal maximum aggregate size in table (2) Warning bands are defined as the area between the JMF limits and the warning limits Job Mix Formula Adjustment (1) The contractor may request adjustment of the JMF according to the department's test method number Have an HMA technician certified at a level appropriate for process control and troubleshooting or mix design submit a written JMF adjustment request. Ensure that the resulting JMF is within specified master gradation bands. The department will have a certified Hot Mix Asphalt, Mix Design, Report Submittals technician review the proposed adjustment and, if acceptable, issue a revised JMF. Not For Contract Administration (2) The department will not allow adjustments that do the following: - Exceed specified JMF tolerance limits. - Reduce the JMF asphalt content unless the production VMA running average meets or exceeds the minimum VMA design requirement defined in table for the mixture produced. (3) Have a certified Hot Mix Asphalt, Troubleshooting, Process Control technician make related process adjustments. If mixture redesign is necessary, submit a new JMF, subject to the same specification requirements as the original JMF. Effective with the December 2015 Letting Standard Specifications

20 Corrective Action (1) When running average values trend toward the warning limits, consider taking corrective action. Document all corrective actions undertaken. Include all test results in the contract files and in running average calculations. (2) Notify the engineer if running average values exceed the warning limits. If two consecutive running average values exceed the warning limits, stop production and make adjustments. Do not restart production until after notifying the engineer of the adjustments made. Do not calculate a new running average until the fourth test after the required production stop. (3) If the process adjustment improves the property in question so that the running average after 4 additional tests is within the warning limits, the contractor may continue production with no reduction in payment. (4) If the adjustment does not improve the properties and the running average after 4 additional tests stays inside the warning bands, the mixture is nonconforming and subject to pay adjustment. (5) If the contractor fails to stop production and make adjustments when required, all mixture produced from the stop point to the point when the running average is back inside the warning limits is nonconforming and subject to pay adjustment. (6) The department will reduce payment for nonconforming QMP HMA mixtures, starting from the stop point to the point when the running average is back inside the warning limits, as follows: PAYMENT FOR MIXTURE PRODUCED WITHIN PRODUCED OUTSIDE ITEM WARNING BANDS JMF LIMITS Gradation 90% 75% Asphalt Content 85% 75% Air Voids 70% 50% VMA 90% 75% [1] For projects or plants where the total production of each mixture design requires less than 4 tests refer to CMM [2] Payment is in percent of the contract unit price for both the HMA Pavement and Asphaltic Material bid items. The department will reduce pay based on the nonconforming property with lowest percent pay. The asphaltic material quantity is based on the JMF asphalt content. The department will administer pay reduction under the Nonconforming QMP Asphaltic Material and the Nonconforming QMP HMA Mixture administrative items. (7) If the running average values exceed the JMF limits, stop production and make adjustments. Do not restart production until after notifying the engineer of the adjustments made. Continue calculating the running average after the production stop. (8) If the air voids running average of 4 exceeds the JMF limits, the material is nonconforming. Remove and replace unacceptable material at no additional expense to the department. The engineer will determine the quantity of material to replace based on the testing data using the methods in CMM 8-36 and an inspection of the completed pavement. If the engineer allows the mixture to remain in place, the department will pay for the mixture and asphaltic material at 50 percent of the contract price. (9) If the running average of 4 exceeds the JMF limits for other properties, the department will pay 75 percent of the contract price for mixture and asphaltic material if the engineer allows the mixture to remain in place. The engineer will determine the quantity of material subject to pay reduction based on the testing data and an inspection of the completed pavement Optional Contractor Assurance General (1) CA testing is optional and is conducted to further validate production testing. The contractor may offer CA data to provide an additional piece of information for the following: Not For Contract Administration 1. Process control decisions. 2. Troubleshooting possible sampling, splitting, or equipment problems. 3. Limiting liability, as defined in CMM 8-36, for nonconforming product as a result of department verification testing. These provisions do not supersede department's rights under [1] [2] Effective with the December 2015 Letting Standard Specifications

21 Personnel Requirements (1) Ensure that an HTP-certified HMA technician certified at a level appropriate for mixture production control testing performs all CA testing and data analysis. Personnel performing CA testing cannot perform QC testing for the same materials Laboratory Requirements (1) Conduct CA testing in a facility conforming to the department's laboratory qualification program. Furnish and maintain a laboratory fully equipped for performing selected CA tests. If the a single laboratory is providing CA and QC data for the same materials, ensure that a separate set of equipment is used to prepare CA samples and run CA tests Testing (1) For the CA program, use the test methods enumerated here in , other engineer-approved methods, or other methods the industry and department HMA technical team recognizes. The contractor may select tests at its option. If using tests in limiting liability, as provided in CMM 8-36, data must exist for the property in question. (2) Perform selected testing as follows: - Bulk specific gravity (Gmb) of the compacted mixture according to AASHTO T166 based on the average of 2 specimens. - Maximum specific gravity (Gmm) according to AASHTO T Air voids (Va) by calculation according to AASHTO T VMA by calculation according to AASHTO R35. (3) There is no specified frequency for CA testing. (4) The department will compare CA samples to QC samples. Obtain CA samples by retaining a QC split portion conforming to the "rule of retained" requirements, as provided in CMM Alternatively the contractor may have CA personnel take an additional sample during production Documentation (1) Report CA test results to the engineer and the contractor's field staff within 2 business days after receiving the samples Allowable Differences (1) Differences between the QC and CA split sample test results are acceptable in limiting liability, as provided in CMM 8-36, if within the following limits: ITEM ALLOWABLE DIFFERENCES Percent passing 12.5 mm sieve 6.0 Percent passing 9.5 mm sieve 6.0 Percent passing 4.75 mm sieve 5.0 Percent passing 2.36 mm sieve 4.0 Percent passing 600-µm sieve 3.5 Percent passing 75-µm sieve 2.0 Bulk specific gravity of the compacted mixture Maximum specific gravity Department Testing Quality Verification Program General (1) The engineer will conduct QV tests to determine the quality of the final product and measure characteristics that predict relative performance. Not For Contract Administration Personnel Requirements (1) The department will provide at least one HTCP-certified HMA technician, certified at a level appropriate for sampling and mixture production control testing, to observe QV sampling of project mixtures. (2) An HMA technician certified at a level appropriate for sampling and mixture production control testing, or an HMA ACT working under the HMA certified technician, will split samples and do the testing. An HMA technician certified at a level appropriate for sampling and mixture production control testing must Effective with the December 2015 Letting Standard Specifications

22 coordinate and take responsibility for the work an ACT performs. No more than one ACT can work under a single certified technician. (3) An HMA technician certified at a level appropriate for sampling and mixture production control testing will ensure that all sampling and testing is performed correctly, analyze test results, and post resulting data. (4) The department will make an organizational chart available at the testing laboratory and to the contractor before mixture production begins. The department's chart will include names, telephone numbers, and current certifications of all QV testing personnel. The department will update the chart with appropriate changes, as they become effective Laboratory Requirements (1) The department will furnish and maintain a facility for QV testing conforming to the department's laboratory qualification program requirements and fully equipped to perform QV testing. In all cases, the department will conduct testing in a separate laboratory from the contractor's laboratory Department Verification Testing Requirements (1) HTCP-certified department personnel will obtain random samples by directly supervising HTCP-certified contractor personnel sampling from trucks at the plant. The department will sample according to CMM Sample size must be adequate to run the appropriate required tests in addition to one set of duplicate tests that may be required for dispute resolution. The engineer will split the sample for testing and retain the remaining portion for additional testing if needed. (2) The department will verify product quality using the test methods enumerated here in (2), other engineer-approved methods, or other methods the industry and department HMA technical team recognizes. The department will identify test methods before construction starts and use only those methods during production of that material unless the engineer and contractor mutually agree otherwise. (3) The department will perform all testing conforming to the following standards: Bulk specific gravity (G mb ) of the compacted mixture according to AASHTO T166. Maximum specific gravity (G mm ) according to AASHTO T209. Air voids (V a ) by calculation according to AASHTO T269. VMA by calculation according to AASHTO R35. (4) The department will randomly test each design mixture at the following minimum frequency: FOR TONNAGES TOTALING: Less than 501 tons... no tests required From 501 to 5,000 tons... one test More than 5,000 tons... add one test for each additional 5,000-ton increment Documentation (1) The engineer will document all observations during QV sampling, and review QC mixture adjustments and QC/CA test results daily. The engineer will note results of observations and inspection records in a permanent field record as they occur Acceptable Verification Parameters (1) The engineer will provide test results to the contractor within 2 mixture-production days after obtaining the sample. The quality of the product is acceptably verified if it meets the following limits: - Va is within a range of 2.7 to 5.3 percent. - VMA is within minus 0.5 of the minimum requirement for the mix design nominal maximum aggregate size. (2) If QV test results are outside the specified limits, the engineer will investigate immediately through dispute resolution procedures. The engineer may stop production while the investigation is in progress if the potential for a pavement failure is present. (3) If production continues for that mixture design, the engineer will provide additional retained sample testing at the frequency provided for in CMM This supplemental testing will continue until the material meets allowable differences or as the engineer and contractor mutually agree. Not For Contract Administration Effective with the December 2015 Letting Standard Specifications

23 Dispute Resolution (1) When QV test results do not meet the specified limits, the bureau's AASHTO accredited laboratory and certified personnel will referee test the retained portion of the QV sample and the retained portion of the nearest available previous QC sample. (2) The department will notify the contractor of the referee test results within 3 business days after receipt of the samples. (3) The department will determine mixture conformance and acceptability by analyzing referee test results, reviewing mixture project data, and inspecting the completed pavement all according to CMM Corrective Action (1) Remove and replace unacceptable material at no additional expense to the department. (2) The department will reduce pay for the tonnage of nonconforming mixture, as determined during QV dispute resolution, if the engineer allows that mixture to remain in place. If production of that mixture design continued during the investigation, the department will also adjust pay for that mixture forward to the next conforming QV or QC/CA point. The department will pay for the affected mixture at 50 percent of the contract price. The department will adjust pay for both the mixture and the asphaltic material Independent Assurance Testing (1) The department will evaluate both the contractor and department testing personnel and equipment as specified in Construction General (1) Construct HMA pavement conforming to the general provisions of Thickness (1) Provide the plan thickness for lower and upper layers limited as follows: NOMINAL MINIMUM LAYER MAXIMUM LOWER MAXIMUM UPPER MAXIMUM SINGLE SIZE THICKNESS LAYER THICKNESS LAYER THICKNESS LAYER THICKNESS [3] in inches in inches in inches in inches 37.5 mm mm mm mm [1] [2] mm [1] [2] 2 3 [1] SMA mixtures use nominal size 12.5 mm or 9.5 mm. [2] SMA mixtures with nominal sizes of 12.5 mm and 9.5 mm have no maximum lower layer thickness specified. [3] For use on cross-overs and shoulders HMA Pavement Density Maximum Density Method Minimum Required Density (1) Compact all layers of HMA mixture to the density table shows for the applicable mixture, location, and layer. Not For Contract Administration Effective with the December 2015 Letting Standard Specifications

24 LOCATION LAYER TABLE MINIMUM REQUIRED DENSITY [1] PERCENT OF TARGET MAXIMUM DENSITY MIXTURE TYPE E-0.3, E-1, and E-3 E-10, E-30, and E-30x SMA [5] TRAFFIC LANES [2] LOWER 91.5 [3] 92.0 [4] UPPER SIDE ROADS, CROSSOVERS, TURN LANES, & RAMPS SHOULDERS & APPURTENANCES LOWER 91.5 [3] 92.0 [4] UPPER LOWER UPPER [1] The table values are for average lot density. If any individual density test result falls more than 3.0 percent below the minimum required target maximum density, the engineer may investigate the acceptability of that material. [2] Includes parking lanes as determined by the engineer. [3] Minimum reduced by 2.0 percent for a lower layer constructed directly on crushed aggregate or recycled base courses. [4] Minimum reduced by 1.0 percent for lower a layer constructed directly on crushed aggregate or recycled base [5] courses. The minimum required densities for SMA mixtures are determined according to CMM Pavement Density Determination (1) The engineer will determine the target maximum density using department procedures described in CMM The engineer will determine density as soon as practicable after compaction and before placement of subsequent layers or before opening to traffic. (2) Do not re-roll compacted mixtures with deficient density test results. Do not operate continuously below the specified minimum density. Stop production, identify the source of the problem, and make corrections to produce work meeting the specification requirements. (3) A lot is defined in CMM 8-15 and placed within a single layer for each location and target maximum density category indicated in table The lot density is the average of all samples taken for that lot. The department determines the number of tests per lot according to either the linear sublot system or the nominal tonnage system defined in CMM (4) A certified nuclear density technician, or a nuclear density ACT working under a certified nuclear density technician, will locate samples and perform the testing. A certified nuclear density technician must coordinate and take responsibility for the work an ACT performs. No more than one ACT can work under a single certified technician. The responsible certified technician will ensure that sample location and testing is performed correctly, analyze test results, and provide density results to the contractor weekly Waiving Density Testing (1) The engineer may waive density testing for one or more of the following reasons: 1. It is impracticable to determine density by the lot system. 2. The contract contains less than 750 tons of a given mixture type placed within the same layer and target maximum density category. (2) If the department waives density testing notify the contractor before paving. The department will accept the mixture by the ordinary compaction procedure as specified in (3) If HMA QC testing is waived under , density testing is also waived. Add subsection to define requirements for paving at temperatures below 40 degrees. This change was implemented in ASP 6 effective with the January 2015 letting Cold Weather Paving Cold Weather Paving Plan (1) Submit a written cold weather paving plan to the engineer at the preconstruction meeting. In that plan outline material, operational, and equipment changes for paving when the air temperature approximately Not For Contract Administration Effective with the December 2015 Letting Standard Specifications

25 3 feet above grade, in shade, and away from artificial heat sources is less than 40 F. Include the following: - Use a department-accepted HMA mix design that incorporates a warm mix additive from the department's approved products list. Do not use a foaming process that introduces water into the mix. - Use additional rollers. (2) Engineer written acceptance is required for the cold weather paving plan. Engineer acceptance of the plan does not relieve the contractor of responsibility for the quality of HMA pavement placed in cold weather except as specified in 450.5(5) Cold Weather Paving Operations (1) Do not place asphaltic mixture when the air temperature approximately 3 feet above grade, in shade, and away from artificial heat sources is less than 40 F unless a valid engineer-accepted cold weather paving plan is in effect. (2) If the national weather service forecast for the construction area predicts ambient air temperature less than 40 F at the projected time of paving within the next 24 hours, confirm or submit revisions to a previously engineer-accepted cold weather paving plan for engineer validation. Upon validation of the plan, the engineer will allow paving for the next day. Once in effect, pave conforming to the engineeraccepted cold weather paving plan for the balance of that work day or shift regardless of the temperature at the time of paving Measurement (1) The department will measure the HMA Pavement bid items acceptably completed by the ton as specified in Revise to specify measurement for a new HMA Cold Weather Paving bid item. This change was implemented in ASP 6 effective with the January 2015 letting. (2) The department will measure HMA Cold Weather Paving by the ton of HMA mixture for pavement placed conforming to an engineer-accepted cold weather paving plan Payment General Revise (1) to add a new HMA Cold Weather Paving bid item. This change was implemented in ASP 6 effective with the January 2015 letting. (1) The department will pay for measured quantities at the contract unit price under the following bid items: ITEM NUMBER DESCRIPTION UNIT HMA Pavement Type E-0.3 TON HMA Pavement Type E-1 TON HMA Pavement Type E-3 TON HMA Pavement Type E-10 TON HMA Pavement Type E-30 TON HMA Pavement Type E-30X TON HMA Pavement Type SMA TON Incentive Density HMA Pavement DOL HMA Cold Weather Paving TON HMA Pavement General (1) The department will pay for the HMA Pavement bid items at the contract unit price subject to one or more of the following adjustments: Not For Contract Administration 1. Disincentive for density of HMA pavement as specified in Incentive for density of HMA pavement as specified in or Reduced payment for nonconforming smoothness as specified in Reduced payment for nonconforming QMP HMA mixtures as specified in (2) Payment for HMA Pavement Type E-0.3, E-1, E-3, E-10, E-30, and E-30x is full compensation for providing HMA mixture designs; for preparing foundation; for furnishing, preparing, hauling, mixing, Effective with the December 2015 Letting Standard Specifications

26 placing, and compacting mixture; for QMP testing and aggregate source testing; for warm mix asphalt additives or processes; and for all materials except asphaltic materials. (3) Payment for HMA Pavement Type SMA, is full compensation for providing HMA mixture designs; for preparing foundation; for furnishing, preparing, hauling, mixing, placing, and compacting the mixture; for QMP testing and aggregate source testing; and for all materials including asphaltic materials and warm mix asphalt additives and processes; for stabilizer, hydrated lime, and liquid antistripping agent if required. (4) If provided for in the plan quantities, the department will pay for a leveling layer, placed to correct irregularities in an existing paved surface before overlaying, under the pertinent paving bid item. Absent a plan quantity, the department will pay for a leveling layer as extra work. (5) Except for SMA mixes, the department will pay for asphaltic materials separately under the Asphaltic Materials bid items as specified in Except for SMA mixes, hydrated lime or liquid antistripping agent, when required, is included in the contract price for the asphaltic material. (6) If the department waives density testing under , the department will not adjust pay under either or (7) Restore the surface after cutting density samples as specified in (1) at no additional cost to the department Disincentive for HMA Pavement Density (1) The department will administer density disincentives under the Disincentive Density HMA Pavement and the Disincentive Density Asphaltic Material administrative items. If the lot density is less than the specified minimum in table 460-3, the department will reduce pay based on the contract unit price for both the HMA Pavement and Asphaltic Material bid items for that lot as follows: DISINCENTIVE PAY REDUCTION FOR HMA PAVEMENT DENSITY PERCENT LOT DENSITY PAYMENT FACTOR BELOW SPECIFIED MINIMUM (percent of contract price) From 0.5 to 1.0 inclusive 98 From 1.1 to 1.5 inclusive 95 From 1.6 to 2.0 inclusive 91 From 2.1 to 2.5 inclusive 85 From 2.6 to 3.0 inclusive 70 More than 3.0 [1] [1] Remove and replace the lot with a mixture at the specified density. When acceptably replaced, the department will pay for the replaced work at the contract unit price. Alternatively the engineer may allow the nonconforming material to remain in place with a 50 percent payment factor. Revise (2) to waive density disincentives for pavement placed in cold weather because of a department-caused delay. This change was implemented in ASP 6 effective with the January 2015 letting. (2) The department will not assess density disincentives for pavement placed in cold weather because of a department-caused delay as specified in 450.5(5) Incentive for HMA Pavement Density (1) If the lot density is greater than the minimum specified in table and all individual air voids test results for that mixture placed during the same day are within +1.0 percent or percent of the design target in table 460-2, the department will adjust pay for that lot as follows: Not For Contract Administration INCENTIVE PAY ADJUSTMENT FOR HMA PAVEMENT DENSITY PERCENT LOT DENSITY ABOVE SPECIFIED MINIMUM PAY ADJUSTMENT PER TON [1] From -0.4 to 1.0 inclusive $0 From 1.1 to 1.8 inclusive $0.40 More than 1.8 $0.80 [1] The department will prorate the pay adjustment for a partial lot. (2) The department will adjust pay under the Incentive Density HMA Pavement bid item. Adjustment under this item is not limited, either up or down, to the bid amount the schedule of items shows. Effective with the December 2015 Letting Standard Specifications

27 (3) The department will restrict incentive payment for shoulders paved integrally with the traffic lane, if the traffic lane does not meet incentive requirements, the department will not pay incentive on the integrally paved shoulder. Add to specify payment for a new HMA Cold Weather Paving bid item. This change was implemented in ASP 6 effective with the January 2015 letting Cold Weather Paving (1) Payment for HMA Cold Weather Paving is full compensation for additional materials and equipment specified for cold weather paving under including costs for preparing, administering, and following the contractor's cold weather paving plan. The department will not pay for HMA Cold Weather Paving for HMA placed on days when the department is assessing liquidated damages. (2) If HMA pavement is placed under and the HMA Cold Weather Paving bid item is not in the contract, the department will pay for the additional costs specified in (1) as extra work. The department will pay separately for HMA pavement under the appropriate HMA Pavement bid items. Not For Contract Administration Effective with the December 2015 Letting Standard Specifications

28 Construction and Materials Manual Chapter 8 Section 36 Materials Testing, Sampling, Acceptance QMP - HMA July 2014 Page 1 Wisconsin Department of Transportation Materials sampling and testing methods and documentation procedures prescribed in chapter 8 of the CMM are mobilized into the contract by standard spec and standard spec Hot Mix Asphalt (HMA) Quality Management Program sampling, testing, materials properties, and documentation as prescribed in CMM 8-36 are called into the contract by standard spec General This section addresses the standard specification for Quality Management Program (QMP), Asphaltic Mixture. The QMP for Hot Mix Asphalt (HMA) is detailed in standard spec The following information is provided as additional reference, interpretation, and guidance for procedures outlined in those specifications. Overview - WisDOT QMP Requirements: - Personnel and required certifications CMM and standard spec ) - Laboratory facilities (CMM and standard spec ) - Random sampling and sampling frequency (CMM and standard spec ) - Required testing (and calculated properties) (CMM and standard spec ) - Mixture bulk specific gravity (G mb ) - Mixture maximum specific gravity (G mm ) - Air voids (V a ) - VMA (voids in mineral aggregate) - Aggregate gradation - Percent binder content - Documentation (CMM and standard spec ) - Records - Control charts - Control limits (standard spec ) - Warning bands - Job mix formula adjustments (CMM and standard spec ) - Corrective action (standard spec ) - Optional contractor assurance (CMM and standard spec ) - Verification program (CMM and standard spec ) The following sections identify and further attempt to clarify procedures used during field production of HMA under the QMP Definitions Rule of Retained: Split samples for comparison testing are retained. In order to test a retained portion of any sample, communications must occur between the department and contractor QMP teams. The department has ownership of QMP required split samples. There is implied joint ownership between contractor and department on any additional QC samples recorded. Limiting Liability: Additional assurance testing can be performed to validate contractor production data. Identifies conforming material for consideration during the dispute resolution process in determining any need for price adjustments (does not exclude price reductions within contractor QMP). Mixture production days: Days of production of a specific design mixture being tested under QMP. No more than two working days is intended for getting test results. Working days: Calendar day, except Saturdays, Sundays, and department-specified holidays. Non-Conforming materials: Mixture not meeting acceptable verification parameters, but allowed to be left in

29 CMM 8-36 QMP - HMA place with appropriate payment reduction. Unacceptable materials: Mixture not meeting acceptable verification parameters and being required to be removed and replaced. Teams: Personnel listed on QMP organizational charts Personnel Requirements (Through HTCP) The following list summarizes minimum personnel requirements and associated certifications to satisfy QMP Asphalt activities. 1. QC: Production process - Sampling and testing: HMATech at a level recognized for mixture production testing (formerly known as HMATech 1). - Production process changes: HMATech at a level recognized for production process control and troubleshooting (formerly known as HMATech 2). - Mix design: at a level recognized for doing mix design work (formerly known as HMATech 3). 2. CA: Production assurance - Sampling and testing: HMATech at a level recognized for mixture production testing (formerly known as HMATech 1). - In the event other properties are being evaluated, have an appropriate certification. 3. QV: Department quality verification - Sampling and testing: at a level recognized for mixture production testing (formerly known as HMATech 1). - Production process change review: at a level recognized for doing mix design work (formerly known as HMATech 3) Laboratory Requirements The laboratory must be: - Furnished with equipment to comply with daily testing and communication requirements (calibrated testing equipment, phones, faxes, copy machines, etc.). - Located at the plant site and operational before production. - A Wisconsin Laboratory Qualification Program participant. Any laboratory producing air void test data to comply with QMP requirements must have a Superpave Gyratory Compactor (SGC). The intent is for the G mm and G mb materials to be tested at the same facility CA Laboratory A separate set of equipment must be used (inclusive of SGC) to compare QC split samples Sampling Hot Mix Asphalt At the beginning of each day the contractor determines the anticipated tonnage to be produced. The frequency of sampling (minimum number of required tests for the day s anticipated production) is defined by the latest (QMP) HMA mixture standard spec A test sample is obtained randomly from each sublot. Example 1 The approximate location of each sample within the prescribed sublots is determined by selecting random numbers using ASTM Method D-3665 or by using a calculator or computerized spreadsheet that has a random number generator. The random numbers selected are used in determining when a sample is to be taken and will be multiplied by the sublot tonnage. This number will then be added to the final tonnage of the previous sublot to yield the approximate cumulative tonnage of when each sample is to be taken. To allow for plant start-up variability, the procedure calls for the first random sample to be taken at 50 tons or greater per production day (not intended to be taken in the first two truckloads). Random samples calculated for July 2014 Page 2

30 0-50 ton should be taken in the next truck (51-75 ton). Example 2 CMM 8-36 QMP - HMA Required Sample Sublot Sample Tonnage Range Random No. ASTM D-3665 Sublot Sample Ton (Random No. x Sublot ton) End of Previous. Range Cumulative Sample Tonnage RN x 600= RN x 900= RN x 1200= This procedure is to be used for any number of samples per day. If production doesn t allow obtaining the next randomly generated sample, then an arbitrary sample will be taken whenever practical to fulfill the sampling frequency requirement defined in standard spec (5) (Document reasons for any non-compliance). Note: If this scenario occurs by definition this sample qualifies as being a random sample within the QMP program frequency requirements. It s intended that the plant operator not be advised ahead of time when samples are to be taken. If the plant operator is involved in recording a Pb (%AC) to match up with the mix sample tonnage, then notification need not be earlier than 60 minutes before the mix sample being taken. If belt samples are used during troubleshooting, the blended aggregate will be obtained when the mixture production tonnage approximates the sample tonnage. For plants with storage silos, this could be up to 60 minutes in advance of the mixture sample that s taken when the required tonnage is shipped from the plant. QC Sample: CA Sample: QV Sample: - Sample size only requires one test portion and one retained portion. - Must be a companion/split sample with QC (for direct data comparison). - If an arbitrary CA sample is taken, the QC team must test the companion split in order to be considered for limiting liability. - Must be directly observed by the engineer. - Engineer takes immediate possession. - The initial split of QV and QV-retained, can be performed by using a quartermaster. If the contractor performs this split, the engineer, before taking possession, must directly observe it Sampling from the Truck Box Sampling will be the contractor's responsibility. Truck box sampling presents some safety hazards because it is necessary to climb atop the truck box and stand on the hot mixture while sampling. Special care should be exercised by the contractor or his designated representative as the sample is procured to prevent falls or burns. A shovel or other department approved sampling device should be of such size and configuration that the sample can be obtained without spilling or roll off. Note: To satisfy this requirement with a flat bottom shovel, it is necessary to attach 2- to 4-inch vertical sides to the shovel. July 2014 Page 3

31 CMM 8-36 QMP - HMA Sample Location in Truck Figure 1 Truck Box Sampling When the last batch has been dumped into the truck box, the sampler must establish a reference point on the surface of the load, either at the high point, if a conical shape exists, or near the middle of the truck box if the surface shows no such conical shape. Then at least three incremental sample points should be established about midway between the previously established point and the sides if the truck and equally spaced around the load as seen below in Figure 1. The sampling shovel or other approved device can be inserted into the upper two to three inches of mixture to extract the sample increments QC Sample Sizes: - Minimum sample sizes are referenced below and are guidance for meeting requirements for test completion. Mixture NMAS Sample Size < 12.5mm (1/2") 70 lb 19.0mm mm (3/4" 1") 100 lb > 37.5mm ( 1-1/2") 160 lb - The total sample for larger NMAS (nominal maximum aggregate size) mixtures will be enough to provide the required minimum testing sample size as defined in Figure 3. - The retained split must be half of the QC sample CA Sample Sizes: Test sample size may vary based on the tests chosen, but still needs to be large enough to accommodate a split for parallel testing and data comparison QV Sample Sizes: Use same guidance as QC sample size (trouble shooting may involve need for a gradation) Sample Identification The contractor is responsible for obtaining and splitting samples. When the sample is an aggregate sample it must be split, placed in bags with plastic liners, and labeled as directed below. When a mixture sample is procured, it must be quartered, place in a bag, and labeled as directed below. Figure 2 provides an example label. The label must include the following items. 1. Contractor Testing Lab and Certified Technician Name 2. QC, QC-ret, QV, QV-ret 3. State project ID 4. Date 5. Sample number 6. Type of asphaltic mixture 7. State mix design ID (250-XXXX-YR) July 2014 Page 4

32 CMM 8-36 QMP - HMA 8. Percent binder 9. Daily tonnage sampled 10. Current G sb Figure 2 Example of Sample Labeling NOTE: The cumulative/total tons representing mix design production are to be recorded on the QC data sheets Reduction of HMA Samples to Testing Size For QC sample reduction the HMA sample in the containers is mixed and quartered. The quartering process should then proceed as follows: Step 1: 1. Quarter the sample into Test and Retained samples. Place entire sample on table, quickly re-mix and quarter to minimize temperature loss. Quarter the Test & Retained samples as shown on Figure 3. For 1/2" mixes start with at least a total of 70 lbs of HMA. Figure 3 Superpave Sample, 70 lbs 2. Diagonal quarters, as indicated on the sketch, must be combined to form the retained sample (A + C) and the test sample (B + D). The retained sample must be bagged, labeled, and stored in a safe dry place. The retained samples may be tested using the rule of retained (see Definitions section). 3. The test sample (B + D) is then further quartered for the specified tests. Continue the quartering process in Step 2 for the test materials until individual samples are in the oven Step 2: The 35 lbs of HMA material for testing from Step 1 is to be further reduced for testing according to the following sketch (see Figure 4). July 2014 Page 5

33 CMM 8-36 QMP - HMA Figure 4 Superpave Sample, (35 lbs) Figure 5 Minimum Testing Sample Sizes For QV (and some CA) samples a Solvent Extraction Gradation (WisDOT Test Method1560) isn t routinely required Use of Alternative Sampling / Quartering Devices (ex: Quartermaster) Use of other devices to assist in the sampling and quartering procedures may be used with approval of the department. The Quartermaster is one such device. A picture of a Quartermaster device is shown in Figure 6. Figure 6 Quartermaster Quartering Device July 2014 Page 6

34 CMM 8-36 QMP - HMA Example Required Testing and Calculated Properties Note: If calculations result in a need to round from an exact half (x.x50), round even. Example: becomes 14.2 and becomes QC Tests QC testing must be completed, and data posted, on the day the sample was taken or as approved by the engineer. For administration of projects requiring only one, two, or three single tests per mix design, apply the following tolerances table for mixture evaluation: - Va = % - VMA = from required minimums for Table AC = within 0.34 of JMF For results not meeting the above ranges, apply pay in accordance with the Produced Outside JMF Limits guidance listed in standard spec (6) CA Tests CA tests, by definition in the standard specifications, are at the contractor s option. A failure to limit liability of one tested property does not jeopardize the limiting liability of all properties. It should be noted that CA testing not completed before department QV samples are taken might not impact recommendations made during dispute resolution unless other communications have occurred between QC/QV teams. The contract language mentions two working days after the sample has been obtained by the contractor as the time within which the CA personnel must respond with data to the QC team. The intent is to provide information and feedback to the QC team as soon as practical in case there is data disagreement. The interpretation is to mean that the time starts when the QC team procures the sample (ex: a QC/QC-ret sample obtained on day 4 and intended to be tested, would need to be selected by CA on day 4, 5 or 6, with results reported no later than day 6). If the QC-retained mixture sample temperature is 230F or higher when delivered to the testing facility, quartering may start immediately. If the temperature is below 230F, place in a 300F oven, until workable for quartering, not to exceed two hours. Microwaves are not to be used to reheat an HMA sample. If the difference between the QC and CA test results are outside the allowable differences, the reason must be investigated immediately CA Data Analysis CA test results are evaluated according to the flow chart Evaluation of CA Test Results, located at the end of this procedure QV Tests The following tests are to be performed in determining product Quality Verification: -Bulk specific gravity of the mixture (G mb per AASHTO T 166) -Maximum specific gravity of the mixture (G mm per AASHTO T 209) -Air voids (Va per AASHTO T 269, calculation) -Voids in the mineral aggregate (per AASHTO R 35, using current field G sb ) July 2014 Page 7

35 CMM 8-36 QMP - HMA WisDOT Test Method No (Revised ) Scope 1. This is a quick method to determine the gradation of the aggregate from an asphaltic mixture when the asphalt content of the mixture is known Apparatus 1. Pans (approximately 12 by 8 by 3 deep), bowls (approximately 10 quarts) or pails (approximately 10 quarts). 2. Balance must be an electronic type with a 5-20 kg capacity and sensitivity to 0.1g. 3. Solvent must be a biodegradable, high flash and nontoxic asphalt extractant Procedure 1. Obtain a representative sample of the mixture. Note that the mixture sample size needs to be larger than the specified minimums required for the mixture aggregate size when determining the gradation (this is in order to account for the weight of the binder being washed out). Dry the sample for 10 to 20 minutes in an oven at 275 F ± 20 F (124C 146C), weigh and record to the nearest 0.1 gram. RAP stockpile samples must be heated until dry, approximately 30 to 60 minutes. 2. Determine the percent asphalt being added to the mixture at the time the sample was obtained (could be from the settings of the asphalt plant for plant produced mixtures) and record. For RAP stockpile samples, use the asphalt content shown for the RAP on the mixture design. 3. Place warm mixture in a pan, pail or bowl and cover with solvent (due to the flammability potential of the solvents, it s not recommended to heat the solvent prior to adding to the mixture sample). Gently agitate the sample, frequently, with a spoon or spatula. Keeping the sample warm during the soaking process will aid in extracting the binder from the aggregate. Continue to soak and agitate the sample for 15 to 30 minutes (30 to 60 minutes for RAP mixtures or RAP stockpiles samples). Note: Excessive soaking time in the solvent will require more water washes and will cause more smoking during the drying operation. 4. Decant the solvent, pouring over a No. 8 sieve nested over a No. 200 sieve. Dispose of the used solvent by an approved method. Add water, agitate and decant over the same sieves. Continue washing with water until the wash water is clear (straw). Material retained on either of the sieves is washed back into the sample. Decant off any excess water. Care should be taken to avoid the loss of particles. Note:It has been the Wisconsin experience that, on average, two full-strength solvent washes, before proceeding with the final water wash will aid in extracting the binder from the aggregate when using RAP mixtures. 5. Dry the sample to a constant weight in an oven or on a hot plate. Stir the cleaned aggregate sample during the drying process to free trapped moisture. Avoid excessive temperature in the drying process. 6. Conduct a sieve analysis on the extracted aggregate (AASHTO Test Method T 27) in order to identify the gradation of the sample Calculation 1. Calculate the total dry weight of the aggregate as follows: Wagg = Wmix * (1-(AC%/100)) July 2014 Page 8

36 Where: Wagg = Total dry weight of the aggregate CMM 8-36 QMP - HMA Wmix = Total dry weight of the mixture determined in section 3.1 AC% = Percent asphalt determined in section Calculate the gradation as required using the dry weight of aggregate (Wagg) as determined above Report 1 The results of the sieve analysis should be reported to the nearest 0.1 percent. 2 Field experience has demonstrated that high flash solvent performs better when applied to an asphaltic mixture sample that is warm. Always follow the specified pre-soaking and rinse conditions. Document anytime in which high flash solvent is soaked other than the prescribed pre-soaking duration. Always comply with the specified test and safety procedures HMA Compaction - AASHTO T Preheat specimen molds (charging funnels, spatulas, etc.) to 300F. 2. Heat sample, in an open container, to a compaction temperature of 275F + 5F in an oven between 285F 320F for no more than 1 hour. If binder modifiers or additives are used, compact to the supplier s temperature recommendations. After quartering to test size, if the mix sample is within the proper compaction temperature range, then the specimen can be compacted without further heating. 3. Place specimen protection disc into the bottom of the mold and charge the mold with the mix sample. The sample size should be enough to attain a final specimen height of 115mm + 5mm and is unique to the mix design. For Wisconsin aggregates and designs a range of g is generally appropriate. Charging the mold should be accomplished in one lift action or motion so as to avoid segregating the sample inside the mold. Additional funnels or scoop chutes may be used in order to accomplish this. 4. Lightly level off the top of the sample and place a specimen protection disc on top. 5. Load the mold into the SGC and compact to the appropriate N des for the mixture type being produced by applying 600kPa 18kPa, at an internal angle of After compaction is completed the specimen is extruded, protection papers removed, the briq is labeled, and cooling by fan is required for a period of 1 hr, not to exceed 2 hrs. If the mixture is extremely fine or tender, then the initial 5-10 minutes of cooling should take place while the specimen is only partially extruded to aid in handling. 7. Height measurements should be recorded and retained with each specimen. 8. Reheat the mold for a minimum of 5 minutes if reusing for the second specimen. All SGCs being used for QMP specimen preparation will conform to the requirements for calibration as listed in the departments Laboratory Qualification Program. Recalibration may be necessary if the testing variation between labs exceeds allowable differences or when a continued bias exists in the data attributed to the preparation of the specimen Bulk Specific Gravity (G mb ) AASHTO T 166 Determine bulk specific gravity, G mb, using AASHTO T166. Weigh the specimens in air and record (designated this weight as A). - Immerse the specimens in 77 2F water bath for 3 to 5 minutes. - Weigh in water, and record (designating this weight as C). - Surface dry the specimens by blotting quickly with a damp towel and then weigh in air (include any water that may drain from voids in specimens), and record (designating this weight as B). - Calculate the G mb to three decimal places (0.001). Determine the average bulk specific gravity for both specimens. If one of the individual specimens deviates by more than ±0.015 from the average, results are considered suspect and a new set of specimens is to be compacted from the contractor retained sample (following the rule-of-retained). If a or greater variability exists between QC and reheated samples (matching QC-retained portion), then a G mb Reheat Correction Factor is to be determined to aid in troubleshooting. G mb Reheat Correction Factor (Calc d to 0.001) = G mb (Un-reheated) / G mb (Reheated) July 2014 Page 9

37 CMM 8-36 QMP - HMA Then apply the correction factor to the reheated sample by: Corr G mb = G mb (Reheated) When comparing the uncorrected G mb to the corrected G mb, if the difference is less than 0.005, then the correction factor will not be used Maximum Specific Gravity of the Mixture (G mm ) - AASHTO T 209 Determine maximum specific gravity, G mm, using AASHTO T Use the appropriate sample size Figure 5. - Subject the G mm sample to the same heating condition and time period as the G mb material. - Begin to cool the sample. While sample is cooling, break up sample to pieces no greater than ¼, and continue to cool to an ambient room temperature. - Place material into a calibrated container and determine the actual dry weight of the sample. - Add 77F water to cover the sample. - Apply required vacuum for minutes, agitating material every 2 minutes minimum. - After the vacuum time period, completely fill the container with 77F water and determine the volume of the sample. - Bowl Method: by suspending the container underwater and weighing - Flask Method: by weighing the container filled with water and sample (in air). - Correct the G mm with a dryback test procedure or by applying a dryback correction factor if aggregates have a moisture absorption of > 2.0% (see next subsection). - Calculate the G mm to three decimal places, Dryback Procedure (Corrected G mm ) for Absorptive Aggregates (AASHTO T 209, Supplemental Procedure for Porous Aggregates) - Run a dryback procedure on Day 1-Sample 1, and determine a dryback correction factor for that test. Average the test dryback correction factor with the design JMF dryback correction factor and apply to the test data for a new G mm. If the new average correction factor changes the G mm by less than then use the design JMF dryback correction factor until otherwise determined by additional testing. - Run a dryback procedure every other day of production on the first test sample, or any time there is a change in binder content greater than 0.1%, or a change in component blend percentages greater than 10% (or 20% combined), using the same averaging method as above to validate the original design JMF dryback correction factor. - If any average dryback correction factor changes the G mm by more than 0.010, check for math or testing error first, otherwise a new dryback correction factor must be established by running drybacks on the next three samples. Average the new dryback correction factors and establish that average as the new JMF dryback correction factor. - If a or greater variability exists between QC and reheated samples (matching QC-retained portion), then a G mm reheat correction factor is to be determined to aid in troubleshooting. It should be calculated to G mm Reheat Correction Factor = G mm (Un-reheated) / G mm (Reheated) - Then apply the correction factor to the reheated sample: Corrected G mm = G mm (reheated) * correction factor. - When comparing the uncorrected G mm to the corrected G mm, if the difference is less than 0.005, then the correction factor will not be used Air Voids (%V a ) AASHTO T 269 The air void (%V a ) determination is a relationship between maximum specific gravity (G mm ) and bulk specific gravity (G mb ). Calculate to one decimal place. July 2014 Page 10

38 CMM 8-36 QMP - HMA Voids in Mineral Aggregate (VMA) VMA is calculated using the aggregate bulk specific gravity, G sb, from the contractor mix design (unless a blend change has occurred in which case a new Gsb will be calculated), the asphalt content (P b determined by ), and the average SGC specimen bulk specific gravity, G mb, as follows (calculate and record to 0.1.): 100 P b = P s (or % stone) Aggregate Effective Specific Gravity, (G se ) In the G se calculation, the volume of the aggregate includes all the aggregate internal void spaces except those that absorb asphalt. Calculate and record to three decimal places (0.001). Where: - G mm = end of previous days average. - P b = end of previous days tank stick. - G b = binder specific gravity from the mix design. Calculate this G se at the beginning of each day and use that value for current day s calculations. If there is a change in binder content then recalculate a new G se with the next available sample (consider it being nonrandom) and average with the previous G se : Where: - G mm = current sample test result. - P b = reflecting the intended change (assumed). - G b = from the mix design. A change in binder source or grade requires a check of the G b Percent of Asphalt Content (Pb) Option is to use a plant gauge reading method and record and chart the Pb reading as close to representing the sample as possible. When calculating the Pb (an additional option for record and charting) use the following equation: Where: - G mm = current sample test result. - Gse = previous day. - G b = mix design. Pb method selected should be used consistently to chart and calculate any related mixture properties for project. Plant gauge readings may involve a calibration procedure and use of a correction/correlation factor. July 2014 Page 11

39 CMM 8-36 QMP - HMA Additional Formulas and Example Calculations 1. Determining the asphalt absorption, P ba, for the following: Given: G se = G sb = G b = Determining the effective asphalt content, P be, of the asphaltic mixture for the following: Given: P b = 5.3 P ba = 0.8 P s = Determining the percent voids filled with asphalt (VFA) for the following compacted mixture: Given: VMA = 14.4 V a = Determining the dust to binder ratio (or DP: Dust Proportion): Given: Pbe = 4.5 % passing = Field Adjusted JMF The JMF may be adjusted in the field based on production test results according to the procedures in WisDOT method When the JMF asphalt content is changed by 0.2% or more (start new running average for G mm ), the compaction target maximum density for the day of the target change can be calculated using the most recent G se and percent asphalt binder (P b ) for the new JMF and G b (binder specific gravity) at 77/77 F from the mix design Field TSR Tests The tensile strength ratio is determined according to the procedures in ASTM Method D After manufacturing the specimens at the plant, they may be tested in an offsite laboratory. Use distilled water for saturating and soaking the test specimens RAP Sampling And Testing The requirement for aggregate gradation testing prior to incorporation to the mix has been eliminated. July 2014 Page 12

40 CMM 8-36 QMP - HMA RAM Stockpile Samples The minimum test sample size must be determined from extracted aggregate gradation size per AASHTO T164. That has been divided into aggregate gradation numbers as follows: Nominal Max Size (mm) Minimum Weight of Test Sample (grams) When test results indicate that a change has occurred in the RAM asphalt content, a change in the design RAM asphalt percentage may be requested by the contractor or the engineer. The request will include at least two recent RAM extractions and also identify all applicable mix designs to be affected. For each affected mix design a new Pbr (Percent binder replacement will be calculated and reported). The requested change will be reviewed for the department by an HTCP Certified HMA Technician at a level recognized for mix design, and a revised JMF can be issued HMA Quality Management Program Documentation The contractor is responsible for documenting all observations, records of inspection, and test results on a daily basis. Results of observations and records of inspection must be noted as they occur in a permanent field record. The testing records and control charts must be available in the QC laboratory at the asphalt plant. The contractor must maintain standardized control charts. Test results obtained by the contractor must be recorded on the control charts the same day the tests are conducted. The aggregate gradation test data must be recorded on the standardized control charts for all randomly selected production samples tested. Sieve sizes for aggregate gradation tests must include the maximum aggregate sieve size, the NMAS sieve, and any following sieves falling below: 1" (25.0mm), 3/4"(19.0mm), 1/2"(12.5mm), 3/8"(9.5mm), # 4 (4.75mm), #8(2.36mm), # 16 (1.18mm), # 30 (600μm), # 50 (300μm) # 100 (150μm) and # 200(75μm) Documentation QC Records In addition to the requirements of the Records subsection of the standard specification, the contractor must provide: - A cumulative tonnage value to the engineer on a daily basis. - Random number generation results and associated tonnage for QMP sampling - Binder Inventories (inclusive of incremental tonnages used to calculate binder usage for test samples and documentation validating calibration checks) - When submitting charts and running average calculation sheets the contractor mix design ID and WisDOT 250 report number must be included on each sheet. Full name of qualified sampler, tester and qualified lab locations should be on individual sample test property worksheets. - Blend change history - Individual sample test property worksheets (Note: More detailed information may be requested or observed during actual production for evaluation purposes. In order to verify compliance with appropriate test procedure requirements, this information needs to be made available during that on-site evaluation). Records should be the original (handwritten or electronic) documents. However, the original source documents should be maintained in the project records. If the data is entered directly into an electronic document then that is acceptable as the source document. If the original document is handwritten and then transferred to an electronic document, the original handwritten document should be maintained as the source document. When supplying the original "source" document, a scanned copy is acceptable. Electronic documents are considered to be acceptable during construction, but the original documents need to be submitted after project completion for final project closeout CA Records When CA testing is completed a CA worksheet is filled out and sent to the QV team. Results from CA testing are posted on the QC charts for the appropriate property. The CA data point should be represented by a unique symbol (ex: blue X ). July 2014 Page 13

41 CMM 8-36 QMP - HMA QV Records Results of QV testing are posted to the appropriate QC charts for air voids and VMA and represented with a unique symbol (ex: red "X") Quality Verification Program Monitoring Contractor QMP Pre-Construction The QV team is responsible for obtaining the following information: - Obtain WisDOT test number of the quality test report for the aggregate source being used. If source quality testing hasn t been completed, notify the department s Bureau of Technical Services laboratory. - Obtain the WisDOT test number of the mix design intended for use or a copy of the contractor's mix design, the review report, if available, from department s Materials Tracking system, and any contract special provisions. - Verify that the QC team personnel have the proper certifications. - Verify that the QC Laboratory facility is WisDOT qualified and has the equipment required by the QMP specification (inclusive of communication devices). Review any procedures for determining reheat correction factors and for the G mm dry back correction factor (if applicable). Discuss any necessary calibrations, or pending recalibrations, for the gyratory compactor and what procedure will be used During Production During production, the QV team should, as often as they feel necessary: 1. Random Sampling: - Check the QC procedures for proper random number generation for all samples. - Verify the QC team is aware they are not to inform the plant before the random sampling will occur. 2. Samples: - Ensure all required samples are being taken for mixture properties and blended aggregate gradations. - Ensure that proper sampling and splitting procedures are being used and the field sample size is large enough to accomplish required testing. - Ensure that stockpile samples are taken and tested for reclaimed asphaltic pavement (RAP) when applicable. - Ensure tensile strength ratio (TSR) tests have been conducted at proper intervals when using anti-stripping agents. - Ensure that the retained samples (mix and blended aggregate) are properly labeled and stored in a dry protected area. 3. Testing: - Observe the reduction of the field samples to test size. - Observe the testing procedures paying attention to temperature of test samples before compaction, compaction efforts, times allotted between tasks, dry backs, etc. - Review data calculations. 4. Control charts: - Check to see that required control charts are present and up to date. - Check to see that control limits and warning bands are accurately drawn. - Check to see that the proper values are being plotted correctly. 5. Documentation: - Check to see that records of compliance are being documented and are up to date. - Check to see that adjustments to mixtures and JMF changes are noted on field records. - Check to see that records have been provided to the QV team on a daily basis Verification Sampling Product quality verification sampling is the responsibility of the department s QV team. July 2014 Page 14

42 CMM 8-36 QMP - HMA Design Mixtures Samples from the truck box will be taken by a member of the contractor QC team, and directly observed by the QV team member. In addition, if the initial split (QV / QV-retained) is performed by the contractor, it is also to be directly observed by the QV team member. The QV team will determine and document the random sampling procedure employed for mixture verification samples. Any or all of the following methods may be used: - Production tonnage. - Specific week during production. - Specific day-of-the-week during production. - Time-of-day. If some other method is used, it should be mutually agreed upon between the QV and QC teams and documented before taking place. The contract language specifies two mixture production days after the sample has been obtained by the contractor as the time within which the QV personnel must respond to the QC team relative to the agreement of data results. The intent is to provide information and feedback to the QC team as soon as practical in case there is data disagreement and the potential need to stop mix production. If the QV mixture sample temperature is 230 degrees F or higher when delivered to the testing facility, quartering may start immediately. If the temperature is below 230F, place in a 300F oven, until workable for quartering, but not to exceed two hours. Microwaves are not to be used to reheat an HMA sample Determining Acceptable Verification Parameters Whenever a flag has been raised by disagreement of QV test results with the defined acceptable parameters, immediate investigation will occur using additional testing, troubleshooting, and dispute resolution actions Additional Testing WisDOT s Bureau of Technical Services laboratory is to test QV-retained and nearest available backward QCretained sample. Example 4 A QV sample taken after QC test 5-3 falls outside acceptable parameters. The WisDOT BTS lab tests retained portion of non-compliant QV sample, along with QC-ret sample 5-3. If that retained sample doesn t exist, the next nearest backward sample is 5-2, etc. If there are no backward retained QC samples, then liability for that mixture may include back to production start-up. The QV team is to provide QC retained split sample testing on the nearest any forward QC sample as soon as practical, and continue at a minimum frequency of 1 in 10 until the QC and QV team mutually agree that the problem has been solved in a forward direction. If comparison testing is being performed by the department to resolve a dispute as demonstrated in CMM , acceptable verification parameters for air voids and VMA will both be determined unless otherwise mutually agreed on by the contractor and the engineer to focus on the material property in dispute (ex. G mm, VMA, etc.). This is to allow something other than a full set of testing when trying to resolve a dispute focused on one testing parameter. In addition, when the QV team is back on the site to obtain the additional QC-retained samples, another QV sample will be taken. Example 5 The QV sample taken after QC test 5-3 falls outside acceptable parameters. The QV team returns to the plant site on day 7 and obtains QC-ret sample 5-4 for testing, QC-ret 5-3 to send to the WisDOT-BTS lab, and directs a new QV sample be taken representing day Troubleshooting The following points are to be considered and re-checked: - Calculations. - QC data trends. - Any CA testing trends or bias. - Equipment calibration records. July 2014 Page 15

43 CMM 8-36 QMP - HMA - Sampling and splitting observations/notes. - Proper use of re-heat correction factors Dispute Resolution For the test results of the QV retained portion, the contract language specifies two working days after receipt of the sample. The receipt day refers to receipt of the sample at the department s Bureau of Technical Services AASHTO accredited laboratory. The intent is to provide test information and feedback to the QC/QV team as soon as practical and targeting within 7 working days of the date of the QV sample. At the completion of dispute resolution testing (QV-ret and nearest backward QC-ret) the WisDOT - Bureau of Technical Services AASHTO accredited laboratory personnel dealing with asphalt mix designs will determine and recommend a range of non-compliant tons based on, but not limited to, the following information: - Project QC data and production trends. - Project CA data. - Any additional forward testing. - JMF changes and cause for change. - Differences between QV, QC and CA comparison testing (single points and running averages). - Affected mixture properties in conjunction with intended application. - Design mixture production and performance history. In determining unacceptable or non-compliant materials, the department s Bureau of Technical Services AASHTO accredited laboratory personnel dealing with asphalt mix designs will provide documentation to the QV team recommending tonnages to be affected. A standard recommendation will be assessed based on data meeting established tolerance levels for split sample testing. A standard recommendation will be assessed based on data meeting the following established tolerance levels for split sample testing: - Gmm Warning Band Limit (WBL): less than or equal to Gmb Warning Band Limit (WBL): less than or equal to Gmm Job Mix Formula Limit (JMFL):less than or equal to Gmb Job Mix Formula Limit (JMFL): less than or equal to The general process flow chart for dispute resolution is shown in Figure 7. Example scenarios are provided in Figure 8. In the event that the range of liability is determined to be at the QV tonnage point (isolated problem), a standard pay adjustment equivalent to 50 tons will be assessed, unless QMP Quality Control pay adjustments are controlling (standard spec ). There is no intent to use multiple pay adjustments, but the lowest percent pay will supersede others. The QV team will further complete documentation responsibilities by determining the dollar amount for any affected mixture tonnage and will forward that information to appropriate project personnel and the QC team. Figure 9 is an example of a spreadsheet used to calculate pay adjustments. July 2014 Page 16

44 CMM 8-36 QMP - HMA Figure 7 HMA Dispute Resolution Flow Chart Footnotes: 1. If the QV "FAILS" during production, pull additional QV sample. 2. If the QC-ret sample does not meet JMFL tolerances (regardless of air voids and VMA), tonnages in question continue forward and backwards until a CA sample has been established to limit liability. 3. If no CA sample limit of liability has been established, the potential is such that the tonnage subject to a pay adjustment can be from the beginning of mix design production to the end. 4. When assessing tonnages for pay reductions, keep the following items in mind: - Consider start-up (1 or 2 day paves). - Look at running averages, did contractor recognize the need for a change, and did they respond to that need? - Consider sample tonnage,how close to start-up are the QC test results? - How far "out" is the sample, is there an explanation/documentation/communication as to why? - Consider making tonnage increments half-way between sample tonnages that were tested. July 2014 Page 17

45 CMM 8-36 QMP - HMA Figure 8 HMA Verification Dispute Resolution Scenarios July 2014 Page 18

46 CMM 8-36 QMP - HMA Figure 8 Example of HMA Verification Dispute Resolution Scenarios (cont'd) July 2014 Page 19

47 CMM 8-36 QMP - HMA Figure 9 Adjustment Calculation Example Footnote: 1. Contact Bureau of Technical Services, Materials Laboratory Unit 2 for further assistance. July 2014 Page 20

48 CMM 8-36 QMP - HMA Evaluation of CA Test Results July 2014 Page 21

49 CMM 8-36 QMP - HMA Evaluation of QV Test Results July 2014 Page 22

50 TOPIC B: Specifications and Construction and Materials Manual Page B-3 Exercises on WisDOT Standard Specification Section Quality Management Program 1. What are the aggregate stockpile gradation requirements (testing and documentation)? 2. In what instances is the contractor required to stop mixture production? 3. What payment reduction percentage is applied to air voids produced within the warning bands? 4. What is the maximum percent wear loss at 500 revolutions for an E-3 mixture? 5. What is the minimum FAA requirement for an E-10 mixture? 6. What is the minimum percent VMA for a 12.5 mixture? 7. What is the acceptable range for fine aggregates passing the 75 micron sieve (#200) in a 19.0 mm mix?

51 TOPIC C: Asphaltic Mix Design

52 TOPIC C: Asphaltic Mix Design Page C-1 Purpose of Asphalt Mix Design The purpose of the mix design is to determine the optimum asphalt content for a specific blend of aggregates to satisfy a given set of specification parameters. The goal of asphalt mix design is to produce an asphalt pavement with specific desirable characteristics. Those characteristics include workability, stability, durability, impermeability, flexibility, fatigue resistance, rut resistance, and skid resistance. Laboratory Design versus Field Production The laboratory mix design system is in place to determine the correct proportions of asphalt cement and aggregate required to produce an asphalt mix with the properties and characteristics needed to withstand the effects of traffic and the environment for many years. Mix design is performed in the laboratory using the Superpave method. This laboratory procedure is created to simulate and predict the effects of traffic on the materials selected. Until the late 1990's, the most common mix design method was the Marshall method, used by about 75 percent of state highway departments, as well as by the U.S. Department of Defense and the Federal Aviation Administration. By the mid-1990's state departments of transportation began to implement the Superpave7 (Superior Performing Asphalt Pavement) method of mix design, also developed under SHRP. While laboratory procedures are developed and used for their predictive capabilities, mixture properties and characteristics may differ between laboratory-produced mixes and plantproduced mixes. (Refer to Figure 5.1, table) Asphalt Mix Design and Job Mix Formula At the conclusion of the laboratory work involved in developing the asphalt mix design, the designer s recommended aggregate structure, the optimum amount of asphaltic binder and its associated mix properties are often referred to as the Job Mix Formula (JMF). The Mix Design Report is documentation of the laboratory evaluation performed while selecting the aggregate structure and asphalt content to be used. The selected material recommendations are then reviewed for meeting specification requirements. The mix design report requirements are specified in WisDOT Test Method 1559 Laboratory Standard Method of Asphaltic Mix Design. This report is also a handy tool for mixture troubleshooting in the field.

53 TOPIC C: Asphaltic Mix Design Page C-2 While the complete mix design contains greater detail about the materials, test trials and completed trial results, the job mix formula provides the actual target values intended for field production. The JMF targets also indicate the baseline values for applying specification tolerance bands in order for the producer to track and maintain quality control.

54 TOPIC C: Asphaltic Mix Design Page C-3 Figure 5.1

55 TOPIC C: Asphaltic Mix Design Page C-4 Figure 5.2 Example Asphalt Mix Design Report

56 TOPIC C: Asphaltic Mix Design Page C-5 Maximum Density Line Relationship The maximum density line is a tool used to analyze and evaluate relationships between the JMF gradation and the voids in mineral aggregates (VMA). A mixture on top of the maximum density line is finer, and inversely, a mixture below the maximum density line is coarser. The VMA will increase as the gradation moves further from the maximum density line whether coarser or finer. The distance on either side of the maximum density line is controlled by the aggregate gradation master range or JMF limits. Most of VMA is determined on the finer end of the grading band. If VMA (goes up) = VTM (goes up), then VMA (goes down) = VTM (goes down) Caution, sometimes a sand or camel hump on the JMF gradation blend may appear at or near the No. 30 sieve. The sand or camel hump at the No. 30 sieve will make an asphaltic mixture very difficult to lay down and place and also may attribute to a tender asphaltic mixture. The sand or camel hump is usually caused by the use of natural river sands. The natural river sands are mostly one-sized particles, which attribute to problems on the No. 30 sieve.

57 TOPIC C: Asphaltic Mix Design Page C-6 VMA, Voids in the Mineral Aggregate Voids in the mineral aggregate (VMA) is the volume of intergranular void space between the aggregate particles of a compacted paving mixture that includes the air voids and the effective asphalt content, expressed as a percent of the total volume of the sample. The purpose of the VMA criteria is to allow enough space for the asphalt in the mixture to provide durability in the asphalt pavement.

58 TOPIC C: Asphaltic Mix Design Page C-7

59 TOPIC C: Asphaltic Mix Design Page C-8

60 TOPIC C: Asphaltic Mix Design Page C-9 Test Property Curves for HMA A Certified Asphalt Technician TPC must be able to analyze and interpret test property curves associated with the HMA design method used. The test property curves are established as best fit graphical plots, and analyzed in relation to the optimum asphalt binder content chosen. Once the optimum binder content is chosen to meet the air void requirement, then all other properties are checked against the specification requirements for compliance. Selection of Design Asphalt Binder Content Using Test Property Curves V a VMA VFA % binder Blend 3 DP %% binder % binder % binder %G mm at N ini %G mm at N max % binder % binder 1 The plotted data also provides additional predictive information useful when considering making changes to the mixture. Regarding the bottom 2 sketches, % Gmm at Nini and % Gmm at Nmax, these properties are actually measured at optimum binder content.

61 TOPIC C: Asphaltic Mix Design Page C-10 Selection of Percent Asphalt Content From the Air Voids Data The design percent AC is selected by knowing the specified Voids in the Total Mixture (VTM) requirement for the type of mixture being produced. The VTM requirement for WisDOT Superpave E-mixtures is 4.0 percent so the designer can go to the air void graph and find the point representing 4.0% air voids, then move across the graph to the intersecting point on the air voids curve and drop to the bottom of the chart to select the percent asphalt content. In the example below, the percent AC (or percent binder, Pb) would be 5.5%. Selection of Percent Asphalt Content Satisfying All Design Criteria The percent AC selected for this E mm mixture is 5.5 percent. All of the calculated and measured asphaltic mixture properties at this asphalt content are evaluated by comparing them to the specified mix design criteria, for example: Asphalt Mix Design Data WisDOT HMA Mix Design at Optimum A.C. Content = 5.5% Requirements VTM or Air Voids (%) = OK VMA (%) = min. OK VFB (%) = OK Th. Max. Sp. Cr. = NA Bulk Sp. Gr. = NA Tensile Strength Ratio = min. OK Recommended Mixing Temp = 275 F -300 F Dust to Asphalt Ratio = OK This E-3 asphalt mix design satisfies all WisDOT requirements for this type of mixture.

62 TOPIC C: Asphaltic Mix Design Page C-11 Dust to Binder Ratio The dust to binder ratio indicates, between 0.6 and 1.2, the most economical proportion to economize asphalt cement in the mixture. An asphalt mix designer is wasting asphalt cement in the mixture if no P-200 mesh material is added, and again, the opposite is true if too much asphalt cement is added. The dust to binder ratio is calculated as follows, using the effective binder content (Pbe) JMF P-200 = 4.9 JMF Pb = 5.5 Pbe = 5.2 (accounts for the absorbed binder) Dust Proportion = P200/Pbe = 4.9/5.2 = 0.9 Increase of P-200 During Mix Design Some asphalt mix designers like to increase the P-200 by some percentage to compensate for anticipated degradation in dryer/drum mixer during production. Be careful when conducting your gradation analysis to use the original P-200 percentage when sampling aggregates off the conveyor belt or stockpile. Anytime you are performing WisDOT 1560 extractions, make sure your P-200 value is referenced from the asphalt mix design report for plant produced mix JMF P Typically P-200 is 1.0 to 1.5% higher in plant produced mix than would be expected from blended stock pile gradations due to aggregate degradation. What happens when the aggregates are conveyed into the dryer/drum mixer of an asphalt plant? At a batch plant, this unit is called a dryer, and at a drum mix plant, it is called a drum mixer. These units are necessary parts of the hot-mix operation for they dry and heat aggregates coming from the cold feed conveyor belts. Cold aggregate is fed into the upper end of the dryer/drum mixer and is picked up by steel angles or flights mounted on the inside of the drum. As the large dryer/drum mixer rotates, the aggregates are picked up by the flights and are dropped. During the drying process, degradation occurs to the aggregates, causing an increase in P-200 for plantmixed aggregate. The main reason for adding the additional percentage of P-200 during the asphalt mix design process is to avoid collapsing VMA and low air voids at project start-up.

63 TOPIC C: Asphaltic Mix Design Page C-12 Asphaltic Mix Design Review Process The asphaltic mix design must be submitted to WisDOT Bureau of Highway Construction Asphalt Mix Design area before project start-up. A WisDOT Certified HMA-MD is responsible for the review. You can contact Judie Ryan at the following address: Jeffrey Anderson, Certified HMATEC-MD WisDOT - Bureau Technical Services 3502 Kinsman Blvd. Madison, WI Phone: (608) Fax: (608) According to Laboratory Standard Method of Asphalt Mix Design, WisDOT Test Method No. 1559, the Asphalt Mix Design report shall be submitted to WisDOT Bureau of Highway Construction Asphalt Mix Design along with a copy to the pertinent district office. Upon receipt of the report and any required material samples to the central office laboratory, a review will be completed and notification of specification compliance will be sent to the submitting lab. Further detail of the report submittal process is listed in the appendix (WisDOT 1559).

64 TOPIC C: Asphaltic Mix Design Page C-13 Superpave Method of Mix Design Chapter Exercises 1. What is the most important factor in predicting asphaltic mixture performance? 2. What should the in-place air voids be for an E-10 mixture? 3. Air voids between and % after two to three years of traffic loading will provide optimum pavement performance. 4. The higher the FAA value, the higher the is. References Hot Mix Asphalt Paving Handbook, US Army Corps of Engineers in conjunction with AASHTO, FAA, FHWA, NAPA, APEA, NACED Hot Mix Asphalt for the Undergraduate, FHWA-RD A Guide for Hot Mix Asphalt Pavement, TAS 30 - NAPA Mix Design Methods for Asphalt Concrete and Other Hot Mix Types, MS-2, Sixth edition, Asphalt Institute

65 1 TOPIC D: Aggregate Blending

66 TOPIC D: Aggregate Blending Page D-1 Aggregate Blending The HMA-TPC Technician will encounter nonuniform stockpile situations, which will require stockpile gradation JMF blends to be recalculated. Being able to compute new stockpile aggregate percentages to identify a new Job Mix Formula (JMF) blend is necessary for asphalt mixture property process control. Procedure for blending of two or more aggregate stockpiles is called the trial and error method. The trial and error method is accomplished by following the steps shown below: Step 1. Step 2. Obtain a gradation analysis from each stockpile or cold feed bin. Samples may be procured from the stockpiles or cold feed bin conveyor belts. All sampling and testing procedures must conform to the prescribed specification methods. The gradation analysis results are only as representative as the sampling method. Obtain the specified JMF limits for each sieve from the aggregate gradation master range. The aggregate gradation master ranges are obtained from Wisconsin standard specification, Section as shown: Sieve Size 25mm 19mm 12.5mm 9.5mm 1-1/2" (37.5 mm) 100 1" (25 mm) /4" (19.0 mm) /2" (12.5 mm) /8" (9.5 mm) No. 4 (4.75 mm) No. 8 (2.36 mm) No. 30 (600 micron) No. 50 (300 micron) No. 200 (75 micron) Enter the specified aggregate gradation master ranges in the upper and lower JMF limits for each specified sieve size in the left corner of the worksheet. Also, enter the specified aggregate gradation master range for the JMF limits in the lower right corner. (See Figure Blending Worksheet Example.) Step 3. Step 4. Select a target value. The goal of aggregate blending is to combine two or more aggregate stockpile sources to meet the specified JMF limits for each sieve. (See Figure Blending Worksheet Example.) Guess the proportion. A percent of each stockpile, incorporated into the asphaltic mixture, is guessed to try to satisfy all of the JMF limits. All of the guessed percentages relating to each stockpile must total 100 percent. (See Figure 6.1 Blending Worksheet Example.)

67 TOPIC D: Aggregate Blending Page D-2 SIEVE SIZE LOWER RANGE BLENDING WORKSHEET UPPER RANGE AGG #1 AGG #2 AGG #2 AGG #4 AGG # ¾ ½ / NO STEP 1 NO NO NO No NO NO STEP 4 SIEVE 50% 50% % % % % STEP 5 STEP 2 ¾ ½ 3/8 NO. 4 NO. 8 NO. 16 NO. 30 No. 50 NO. 100 NO (.50)=50 100(.50)= = 100 = 100 ok (.50)= (.50)= = 83.8 = (.50)= (.50)= = 56.5 = (.50) = (.50)= = 36.7 = ok (.50)= (.50)= = 28.9 = 28.9 ok STEP (.50)= (.50)= _15.4 = 16.4 = 16.4 ok (.50)= (.50)= = 8.3 = 8.3 ok (.50)= (.50)= = 3.6 = 3.6 ok 3-8 Figure 6.1 Blending Worksheet Example

68 TOPIC D: Aggregate Blending Page D-3 Step 5. Calculate the combined gradation. Each gradation must be multiplied by the guessed percentage to determine the new percentage value. Once the new percentage values have been calculated, each sieve row is added together to determine the new JMF blend. The trial and error method may become very tedious and time consuming. A time saving measure is to calculate two or three key sieves, such as 3/4, No. 8 and No If the combined key sieve aggregates satisfy the JMF limit requirements, then calculate the other sieves to see whether the combined aggregate blend does satisfy all other JMF limits. (See Figure 6.1- Blending Worksheet Example.) Step 6. If the combined aggregate blend does not satisfy all the JMF limit requirements, try again. (See Figure 6.1- Blending Worksheet Example.) Let s try an example: (See Figure Blending Worksheet Example.) Step 1. Step 2. Step 3. Obtain a gradation analysis from each stockpile or cold feed bin. Obtain the aggregate gradation master range specification limits for a MV3 asphaltic mixture. Select a target value. Usually the target is midrange of the JMF specification limits. Step 4. Guess the proportions. Let s try aggregate #1-50% and aggregate #2-50%. Remember the sum of percents must total 100 percent (50% + 50% = 100%). Step 5. Calculate the combined gradation, for example: Sieve AGG#1 AGG#2 JMF Blend (50%) (50%) 3/4 100 x.50 = x.50 = = 100 No x.50 = x.50 = = 28.9 No x.50 = x.50 = = 3.6 Analyze all data to determine if the combined aggregate gradation meets the specified JMF limits. In the 50/50 blend, all sieves meet the JMF limit specification except the 1/2" and 3/8" sieves. Step 6. Try again. The combined aggregate blend does not satisfy all the JMF limit parameters. Repeat procedure with another guess. Example 2: Refer to Figure Blending Worksheet Example. Let s try AGG #1 = 20% and AGG #2 = 80%. The reasoning for the trial is because the 1/2" and 3/8" sieves were lower than the JMF specification limits. Raising the percent AGG #2 to 80 percent should increase the percent passing on the 1/2" and 3/8" sieve. Let s try once again. The combination of 20 percent AGG #1 and 80 percent AGG #2 does satisfy the combined aggregate gradation master band (See Figure Blending Worksheet Exercise.)

69 TOPIC D: Aggregate Blending Page D-4 BLENDING WORKSHEET STEP 6 SIEVE 20% 80% % % % % ¾ 100(.20)=20 100(.80)= = 100 = 100 ok 100 ½ 67.5(.20)= (.80)= = 93.5 = 93.5 ok /8 16.6(.20)= (.80)= = 80.3 = 80.3 ok NO (.20)= (.80)= = 57.4 = 57.4 ok NO (.20)= (.80)= = 45.0 = 45.0 ok NO (.20)= (.80)= = 35.8 = 35.8 na NO (.20)= (.80)= = 25.0 = 25.0 ok 7-40 No (.20)= (.80)= = 12.2 = 12.2 ok 5-25 NO (.20)= (.80)= = 6.4 = 6.4 na NO (.20)= (.80)= = 4.8 = 4.8 ok 3-8 SIEVE % % % % % % ¾ ½ 3/8 NO. 4 NO. 8 NO. 16 NO. 30 No. 50 NO. 100 NO. 200 Figure 6.2 Blending Worksheet Example

70 TOPIC D: Aggregate Blending Page D-5

71 TOPIC D: Aggregate Blending Page D-6 Federal Highway Administration (FHWA) 0.45 Power Chart The FHWA 0.45 power chart is used to plot and analyze a gradation analysis. The FHWA 0.45 power chart is a very useful tool for evaluating the aggregate gradation versus voids in mineral aggregate (VMA) property. The upper and lower JMF specification limits for the specified aggregate gradation, combined or single aggregate gradation, and the maximum density line shall be plotted on the FHWA 0.45 power chart. (See Figure FHWA 0.45 Power Chart.) Maximum Density Line The maximum density line in Wisconsin is a straight line plotted from the origin through the first sieve which has material retained. For example, in Figure FHWA 0.45 Power Chart, the 1/2" sieve is identified as the first sieve having material retained. The maximum density line is drawn from 0.0 origin through the 1/2" sieve at 93.5 percent. (The maximum density curve drawn through the actual percent passing at the nominal maximum sieve has proven effective in evaluating many Wisconsin mix designs.)

72 TOPIC D: Aggregate Blending Page D-7 Figure 6.3 Federal Highway Administration (FWA) 0.45 Power Chart

73 TOPIC D: Aggregate Blending Page D-8 AGGREGATE BLENDING EXERCISES 1. Combine three (3) aggregates to meet a gradation specification. Refer to Figures 6.4 and Blending Worksheet Problem for JMF blending of three aggregates. 2. Combine four (4) aggregates to meet a gradation specification. Refer to Figures 6.5, and Blending Worksheet Problem for JMF blending of four aggregates. The aggregate gradation master ranges are obtained from Wisconsin Standard Specification, as shown: Sieve Size 1 2 (19.0 mm) 3 (12.5 mm) 4 1-1/2" (37.5 mm) 100 1" (25 mm) /4" (19.0 mm) /2" (12.5 mm) /8" (9.5 mm) No.4 (4.75 mm) No.8 (2.36 mm) No.30 (600 micron) No.50 (300 micron) No.200 (75 micron) FHWA 0.45 POWER CHART EXERCISES 1. Use the results of aggregate blending problem # 1 to plot the maximum density line, JMF limits, and gradation analysis on an FHWA 0.45 Power Chart. Refer to Figure 6.6 FHWA 0.45 Power Chart to plot the data. 2. Use the results of aggregate blending problem # 2 to plot the maximum density line, JMF limits, and gradation analysis on an FHWA 0.45 Power Chart. Refer to Figure 6.7 FHWA 0.45 Power Chart to plot the data.

74 TOPIC D: Aggregate Blending Page D-9 SIEVE SIZE LOWER RANGE UPPER RANGE AGG #1 AGG #2 AGG #3 AGG #4 AGG # ¾ ½ / NO NO NO NO No NO NO SIEVE % % % % % % ¾ ½ 3/8 NO. 4 NO. 8 NO. 16 NO. 30 No. 50 NO. 100 NO. 200 Figure 6.4 Blending Worksheet Problem

75 TOPIC D: Aggregate Blending Page D-10 SIEVE BLENDING WORKSHEET % % % % % % ¾ ½ 3/8 NO. 4 NO. 8 NO. 16 NO. 30 No. 50 NO. 100 NO. 200 SIEVE % % % % % % ¾ ½ 3/8 NO. 4 NO. 8 NO. 16 NO. 30 No. 50 NO. 100 NO. 200 Figure Blending Worksheet Problem

76 TOPIC D: Aggregate Blending Page D-11 SIEVE SIZE LOWER RANGE UPPER RANGE AGG #1 AGG #2 AGG #3 AGG #4 AGG # ¾ ½ / NO NO NO NO No NO NO SIEVE % % % % % % ¾ ½ 3/8 NO. 4 NO. 8 NO. 16 NO. 30 No. 50 NO. 100 NO. 200 Figure 6.5 Blending Worksheet Problem

77 TOPIC D: Aggregate Blending Page D-12 SIEVE % % % % % % ¾ ½ 3/8 NO. 4 NO. 8 NO. 16 NO. 30 No. 50 NO. 100 NO. 200 SIEVE % % % % % % ¾ ½ 3/8 NO. 4 NO. 8 NO. 16 NO. 30 No. 50 NO. 100 NO. 200 Figure Blending Worksheet Problem

78 TOPIC D: Aggregate Blending Page D-13 SIEVE BLENDING WORKSHEET % % % % % % ¾ ½ 3/8 NO. 4 NO. 8 NO. 16 NO. 30 No. 50 NO. 100 NO. 200 SIEVE % % % % % % ¾ ½ 3/8 NO. 4 NO. 8 NO. 16 NO. 30 No. 50 NO. 100 NO. 200 Figure Blending Worksheet Problem

79 TOPIC D: Aggregate Blending Page D-14 Figure 6.6 FHWA 0.45 Power Chart

80 TOPIC D: Aggregate Blending Page D-15 Figure 6.7 FHWA 0.45 Power Chart

81 TOPIC E: Quality Control Organizational Plan

82 TOPIC E: Quality Control Organizational Plan Page E-1 Quality Control Organization Plan According to the Quality Management Program, Asphaltic Mixture, the contractor shall provide and maintain a quality control program. The quality control program is defined as all activities, including mix design, process control inspection, sampling and testing, and necessary adjustments in the process that are related to the production and placement of a hot mix asphaltic pavement which meets the requirements of the specification. Shown below is an example of a quality plan: EXAMPLE QUALITY CONTROL PLAN Crushed Aggregate and Hot Mix Asphalt Project #: Project Location: County: Construction Supervisor: Project Engineer: Type of Work: Project Foreman: OCP Prepared by: THE COMMUNICATION LINK Telephone Company Fax Permanent Lab Telephone Permanent Lab Fax Project Foreman, Mobile & Pager Mobile & Portable Lab Telephone & Fax

83 TOPIC E: Quality Control Organizational Plan Page E-2 HTCP CERTIFIED PERSONNEL THE PRIMARY QUALITY CONTROL PERSONNEL THAT WILL BE WORKING ON THIS PROJECT Name Responsibilities Certified AGGTEC-I, HMA-IPT, HMA- Will be overseeing the general operation of the TPC, HMA-MD lab. Certified AGGTEC-I, AGGTEC-II, Will be overseeing the hot mix asphalt design HMA-IPT, HMA-TPC, HMA-MD, and testing for this project Superpave Upgrade Certified AGGTEC-I, HMA-IPT, HMA- TPC, NUCDENSITYTEC-1 Certified TRANSPORTATION MATERIAL SAMPLING Certified AGGTEC-I Certified AGGTEC-I, HMA-IPT, HMA- TPC, PROFILOGRAPH, NUCDENSITYTEC-1 Certified NUCDENSITYTEC-1 Certified NUCDENSITYTEC-1, PROFILER Will be the primary laboratory technician for this project. Will be performing aggregate production and placement samples, as well as the hot mix asphalt testing for this project. Will be certified AGGTEC- I in May and may perform aggregate sampling and testing work on this project. Aggregate plant operator and performs stockpile sampling during aggregate production. Aggregate plant operator and performs stockpile sampling during aggregate production. All laboratory personnel that may be working on this project have direct and open communication with each other, plant personnel, road crews, and company representatives through the project. LABORATORY AND EQUIPMENT REQUIREMENTS The permanent and portable laboratories are certified according to the Wisconsin Qualified Laboratory Program. The Quality Manual is available in the lab.

84 TOPIC E: Quality Control Organizational Plan Page E-3 During aggregate production and the hot mix asphalt design process, the laboratory facility used for testing will be the permanent laboratory facility. The lab is located. During hot mix asphalt placement, the laboratory facility used for testing will be the portable laboratory facility. The lab will be located, along with the Hot Plant, at Pit. The Pit is located on Road in the Town or City of. Aggregate placement testing will be performed at the laboratory we are working in at the time aggregate is being placed, either the permanent or portable laboratory. WisDOT personnel will be notified of which lab we will be working out of at that time. Retained samples, quality control charts, and process documentation will be maintained at the laboratory being worked in at that time. Control charts and testing documentation will be updated and completed daily. Laboratory equipment will be calibrated and inspected according to WisDOT and QMP procedures and/or by manufacturer s recommendations. All records are maintained in the Quality Manual, which is located in the lab. Equipment such as scales, sieves, and thermometers will be inspected daily for excess wear and/or damage. Before startup in the portable laboratory, the laboratory shall be leveled, the Superpave Gyratory Compactor shall be calibrated, and scales shall be checked with the weight set. Records shall be kept for these procedures and maintained in the Quality Manual. All sampling and testing procedures will be performed according to the Quality Management Procedural Manual and other WisDOT specifications and project documents. Stockpile samples of aggregates will be performed during the aggregate production. HOT MIX ASPHALT DESIGN This project requires a 12.5mm Superpave design and a 19.0mm Superpave design. The hot mix asphalt designs are not completed at this time. The designs will be started approximately, on the completion of the designs and approval by WisDOT Central Office; they will forward them to appropriate WisDOT District project. SOURCE #1 AGGREGATE SOURCES SOURCE #2

85 TOPIC E: Quality Control Organizational Plan Page E-4 SOURCE STUDIES: Pit has been determined to be satisfactory according to WisDOT test number. (soundness = 0.4%, wear = 2.75%, 13.0%) Pit has been determined to be satisfactory according to WisDOT test number. (soundness = 1.0%, wear = 4.1%, 18.3%) PROCESS CONTROL INSPECTION AND ADJUSTMENT AGGREGATE PRODUCTION PLANT The aggregate production plant operator and crew perform control inspection of the crushing equipment and site on a daily basis. This includes inspecting the general condition of the equipment, adjusting the jaw and cone settings, observing screen conditions, monitoring fugitive dust control and site appearance, and observing changes in the raw material and in stockpiling conditions. Aggregate process adjustments may include screen changes, jaw and cone setting adjustments, and addition or rejection of sand. Process adjustments will be made according to results obtained from laboratory analyses. HOT MIX ASPHALT PLANT The hot plant operator and crew perform control inspection of the hot plant equipment and site on a daily basis. This includes inspecting the general condition of equipment, inspecting the drum end seals and ductwork, and calibrating the asphalt and aggregates zero and span scales. Hot mix asphalt process adjustments may include gradation changes, moisture changes, and % asphalt cement changes. Process adjustments will be determined by laboratory analyses and recorded by laboratory personnel. LABORATORY The on-site laboratory includes a water supply, electrical power, telephone, fax, and all of the necessary equipment and supplies to perform quality control testing as specified in the QMP provisions. Laboratory technicians perform control inspection of laboratory equipment on a daily basis. This includes inspecting the general condition of equipment, performing maintenance and calibrations, if necessary, maintaining quality control charts and process documentation, and maintaining open communication with project personnel.

86 TOPIC E: Quality Control Organizational Plan Page E-5 WisDOT standard specification, Personnel Requirements, specifically states under Contractor s Quality Control that the contractor shall have an HMA-TPC Technician available to make any necessary process adjustments. An organizational chart, including names, telephone numbers, and current certification of all those responsible for the quality control program shall be posted in the contractor s laboratory prior to the beginning of asphaltic mixture production. This chart shall be updated with appropriate changes as they become available!! See an example of a completed Quality Control Organizational Chart in Figure 4.1 An example of the Quality Control Organizational Chart has been provided for your company s use - See Figure 4.2. The quality control organizational plan, required by WisDOT specification, will be one of your most important communication tools. The quality control organizational plan will be the first step in developing a quality control team. The first section of the quality control organizational plan must list actual personnel working on the specific project or job. For instance, the first section of the list must include names of the certified technicians, along with their level of pertinent certification and expiration dates, plant foreman, paving foreman, and project manager. The second section of the chart may include the company s regional manager(s). The third section of the chart may involve corporate personnel, such as vice president, quality control manager, and HMA-MD certified people. Finally, the last portion of the chart may include a list of certified QV personnel, the project engineer, and the construction supervisor. Remember, the whole concept of QC/QV revolves around the aspect of partnering. As an HMA- TPC Technician, you have a responsibility to communicate with the QC/QV teams as a start to the decision-making process. It is a very good idea before project start-up to schedule a preconstruction meeting to begin positive open communication channels between the QC and QV teams. Open communication channels are essential to every QC/QV project relationship. Usually an HMA-TPC Technician is responsible for multiple projects, so make sure you carry a copy of each organization s quality control plan for each specific project. For instance, a problem may arise, and you may be able to solve the particular instance by phone or fax machine. Sometimes it is possible to troubleshoot a project using a fax to analyze the data without ever actually visiting the plant site. Again, COMMUNICATION will aid you in process control troubleshooting decisions.

87 TOPIC E: Quality Control Organizational Plan Page E-6 Request for Job Mix Formula Change The JMF represents the control limits on a control chart. Each specified sieve is regulated by JMF tolerances. Refer to WisDOT Standard Specifications, Section , for the actual JMF tolerances. Job Mix Formula Adjustment A request for a job mix formula adjustment may be made to the engineer by the contractor. The requested change will be reviewed by the WisDOT department HMA-MD Technician. If acceptable, a revised job mix formula shall be issued. The number of adjustments will be limited according to the current WisDOT department policy. Adjustments to conform to actual production shall not exceed the tolerances specified for the job mix formula limits. Regardless of such tolerances, the adjusted job mix formula shall be within the mixture specification master gradation bands. Should a redesign of the mixture become necessary, new job mix formula asphalt content may only be reduced if the production voids in mineral aggregate meets or exceeds the minimum voids in mineral aggregate design requirement for the mixture being produced. The request for JMF change must be requested in writing. See Figure 1 - Example - Request for JMF Change Form. The request for JMF change form should have a list of items as per Figure 1. The purpose of the JMF change form is to provide verification and records of the new JMF requests. The JMF change form is a permanent project record and shall be maintained as part of the project records. CMM Job Mix Formula (JMF) Changes During a construction season, JMF blend single aggregate component percentages are not allowed to go to zero (elimination). Elimination or addition of any new aggregate components requires a new mix design. No JMF change requests are to occur prior to completion of three individual production tests. Prior production test results need not be tied to state work. The contractor will notify the engineer of the proposed change in written form using a "Request for JMF Change" (Figure 1). Comments must include the sample test number that indicates when the change is to become effective. Production changes or formal requests for JMF changes may not cause any target value to exceed mix design requirement limits of standard spec table 460-1or standard spec table 460-2, however production tolerances may allow for field mixture properties to exceed those targets. The requested change may become effective at a test point up to four individual tests before the test when the request was formally made. Documentation that the contractor and engineer had discussed a possible JMF Change must exist for the change to occur at a point prior to the test number on the formal request. Further changes, subsequent to the original property change, will not be granted until six additional individual test points (within the normal sampling frequency) for the affected mix (test) property have been generated. Each JMF sieve will be considered as an individual mix (test) property. Control chart(s) for the affected property(ies) will accompany the "Request for JMF Change" (Figure 1). An example JMF mix design worksheet is shown in Figure 2. WisDOT Policy JMF Changes for Asphaltic Mixtures WisDOT Test Method 1559/WisDOT Lab Standard

88 TOPIC E: Quality Control Organizational Plan Page E-7

89 TOPIC E: Quality Control Organizational Plan Page E-8 Quality Management Process Flow A quality management process flow has been developed to guide the appropriate sequence of events for troubleshooting a QC/QV project. In summary, the quality management process guide consists of two main branches, QC and QV team. The first step is to conduct a preconstruction meeting to review all quality management specifications before project start-up. For example, WisDOT standard specification states The contractor shall furnish and maintain a laboratory at the plant site. The laboratory shall be furnished with the necessary equipment and supplies for performing contractor quality control testing. During the preconstruction meeting, topics of discussion should be the desired location, utility hook-ups, and date(s) laboratory will be set up prior to project start-up. The main purpose of the quality management process flow is to establish open communication channels and ensure each team, QC and QV, understands its specific responsibilities and occupational duties. Asphaltic Mixture Sampling Plan As an HMA-IPC Technician, you have experienced: Random sampling of asphaltic mixtures Sampling from stockpiles and off conveyor belts Sampling asphalt mixture from a truck box Reduction of asphaltic mixture samples to test size

90 TOPIC E: Quality Control Organizational Plan Page E-9 Random Sampling Exercises 1. Who is responsible for making a JMF adjustment in the field? 2. The production for one day will be 2700T. How many samples are required? 3. Determine the tonnage sampling plan for 2700 tons. Tonnage Increment x Sample No. Range Random # Random # +Prev. Increm. Final Sample Ton

91 TOPIC F: Data Entry Note: Check the CMM link to verify the latest version

92 TOPIC F: Data Entry F-1 MATERIAL DATA REPORTING FOR QC, QA, QV, IA ON HIGHWAY CONSTRUCTION PROJECTS The above is from the Atwood Systems website:

93 Atwood Systems Software in use by Wisconsin Department of Transportation PRODUCT NAME DESCRIPTION USAGE DEPLOYMENT TARGET J Project Tracking ( PT ) Manages all phases of a project. FIT provides field data to this WISDOT Staff. system. WISDOT LAN Materials Tracking (MTS) Manages all materials testing and reporting. MIT provides field data WISDOT Staff. to this system. Data collected is sent to Project Tracking via Atwood. WISDOT LAN Field Information Tracking (FIT) Provides data collected from project sites and merged data from Field WISDOT Staff. Manager. Contractors. Data collected is sent to Project Tracking via Atwood. Materials Information Tracking ( MIT ) Captures QV, QA, IA and Verification test reporting for a multitude of WISDOT Staff. materials. Field job sites Field job sites MRS Hot Mix Asphalt Asphalt QC data collection by Lot and Sub-lot by date. Used by Contractors. Used by Contractors. Field job sites MRS Portland Cement Concrete Concrete pavement, structures ( by lot I sub-lot and thickness QC data collection. Used by Contractors. Field job sites MRS International Roughness Index Pavement smoothness QC 1 QA data collection. WISDOT Staff. Contractors. Field job sites Page 1

94 eguide Generates Sampling and Testing Guide WISDOT Staff. Contractors. Atwood Web Site Highway Quality Management System Data management and reporting web site. Hosts all QMP data; materials reports. WISDOT Staff. Contractors. Atwood Web Site Activity Reporting System Reports on project activity and material test results. WISDOT Staff. Atwood Web Site Data Management System Manages data replication I synchronization from field sites to MTS and Project Tracking. Atwood Systems Atwood Systems Page2

95 Construction and Materials Manual Chapter 8 Section 10 Materials Testing, Sampling, Acceptance Materials - General Wisconsin Department of Transportation Materials sampling and testing methods and documentation procedures prescribed in chapter 8 of the CMM are mobilized into the contract by standard spec and standard spec Control of Materials Approval of Materials Used in Work The service life of a highway is dependent upon the quality of the materials used in its construction, as well as the method of construction. Control of materials is discussed in standard spec The spec provides that only materials conforming to the requirements of the contract must be used, and the contractor is responsible for furnishing materials meeting specified requirements. Only with permission of the engineer can the contractor provide materials that have not been approved, as long as the contractor can provide evidence that the material will be approved later. The department's intention is to hold payment of items until the required materials information is provided by the contractor. The standard specs encourage recovered and recycled materials to be incorporated into the work to the maximum extent possible, consistent with standard engineering practice. Standard spec and Wisconsin statute require the use of American made materials to the extent possible. On federally funded projects, all steel products must be produced in the United States, and manufacturing and coating processes must be performed in the U.S. These "Buy America" requirements are discussed in CMM (12) Material Coordinators Section revised to correct material coordinator designations Contractor and Department Designated Materials Persons Standard spec requires the contractor to designate a Contractor's Project Materials Coordinator (CPMC) who will be responsible for submitting all contractor materials information to the engineer. The department should also designate a WisDOT Project Materials Coordinator (WPMC) who will be in direct contact with the contractor's designee. Standard spec requires the CPMC to communicate with all subcontractors to ensure that sampling, testing, and associated documentation conforms to the contract. The contract also makes the CPMC responsible for submitting materials information from the prime contractor and subcontractors to the WPMC, promptly reporting out-of-specification test results, collecting and maintaining all required materials certifications, and regularly communicating with the WPMC regarding materials issues on the contract. The WPMC should provide a project-specific sampling and testing guide (EGuide) to the contractor at the preconstruction conference. The EGuide is created by clicking on the "Systems Links" tab and following "Site Log-In" sub-tab for EGuide (a username and password are required): Both the CPMC and WPMC should review and supplement the E-guide before work operations begin to ensure that testing methods, frequencies, and documentation requirements conform to the contract. The CPMC and WPMC are charged with working together throughout the life of the contract to ensure that contract materials requirements are met and any issues that might arise related to either non-conformance or non-performance are dealt with promptly. The ultimate goal is to make sure that problems with materials are brought to light and timely corrective action taken before those materials problems compromise the quality or acceptability of the completed work. The CPMC should coordinate contractor materials related activities and do the following: - Establish methods and work expectations with the WPMC. - Provide all QMP test data and control charts from the prime contractor and subcontractors. - Deal with all materials-related concerns from the WPMC. The WPMC is responsible for administration of the contract with regards to contract materials requirements and should do the following: - Communicate or meet weekly with the CPMC to discuss outstanding materials issues on the contract. - Monitor the submittals from the CPMC to ensure timeliness and completeness. May 2015 Page 1

96 CMM 8-10 Materials - General - Review contractor submittals to verify materials requirements are met. - Inform the Project Leader of non-conforming materials issues and discuss actions to be taken. - Prepare materials documentation for inclusion into the project files. Materials coordinators' training is available and recommended for all contractor and department personnel who work with materials on WisDOT projects. The training provides details about the department's materials acceptance process as well as the roles and responsibilities of project materials coordinators. Materials coordinators' training can be accessed at: Approval of Materials All materials used in a project are subject to the engineer's approval before incorporation into the work. Approval of materials is discussed in standard spec Approval is generally accomplished by material tests and/or analysis. This can be done by using approved product lists, certification, or sampling and testing. Unless the contract specifies otherwise, the contractor must follow manufacturer's recommended procedures for products incorporated into the work. Refer to CMM 8-45 for details of acceptance types Quality Management Program Sampling and testing on WisDOT projects is performed according to the Quality Management Program (QMP). QMP is presented in CMM 8-30 and the following CMM sections Independent Assurance Program The Independent Assurance Program (IAP) is an element of the Quality Management Program intended to ensure that test data from project acceptance testing is reliable, including sampling procedures, testing procedures, and testing equipment. Quality verification (QV), quality assurance, (QA), and quality control (QC) are integral parts of the IAP. Further information about the Independent Assurance Program can be found in CMM Quality Verification (QV) Quality verification (QV) sampling is done by a department representative, and is taken independently from the quality control samples to validate the quality of the material Quality Assurance (QA) Under the quality assurance (QA) program, a department representative observes sampling and testing performed by the contractor, by testing split samples. Further detail about quality verification and quality assurance is provided in CMM Quality Control (QC) Quality control for materials testing includes all contractor/vendor operational techniques and activities that are performed or conducted to fulfill the contract requirements Nonconforming Materials General The department does not want material not meeting contract specifications incorporated into the work. Standard spec gives the engineer the authority to either reject nonconforming materials or to allow the nonconforming materials to remain in place. If materials are found to be unacceptable before or after placement into the work, the engineer may reject the materials, and the contractor must remove the materials from the site at no cost to the department. Materials that have been tested and approved at their source or otherwise previously approved, but have become damaged or contaminated before use in the work, are also subject to rejection by the engineer. To ensure consistency in the decisions made for acceptance of non-conforming material or workmanship, the engineer should involve the region oversight engineer before finalizing any decision. This will help keep central office informed about contractor or material problems that may require action with a change in specifications or discipline of a contractor. If any technical questions remain about the acceptance or rejection of nonconforming materials refer to the appropriate technical expert in the Bureau of Technical Services Nonconforming Materials Allowed to Remain in Place Deciding Whether or not to Allow Material to Stay in Place Good engineering judgment is required when making decisions on nonconforming materials. The engineer may choose to approve nonconforming materials, allow them to remain in place, and adjust the contract price. When making the decision to direct the contractor to remove and replace the materials versus leave the materials in place, it's important to consider the following: May 2015 Page 2

97 CMM 8-10 Materials - General - Long-term consequences on quality and durability. - Implications on the project's life cycle costs, service life, serviceability, and maintenance. - Socioeconomic, environmental, and aesthetic considerations. - Impacts on traffic, staging, and construction timeframes Deciding Whether or Not to Apply Price Reduction After the engineer has decided to allow nonconforming materials to remain in place, he or she must carefully evaluate each situation in deciding whether to take a price reduction. The goal is to achieve consistency statewide in administering price reductions for nonconforming materials that are allowed to remain in place. Results of retests and related quality tests should be considered. The following list includes some examples of the types of factors the engineer must consider to decide if a price reduction is warranted and how much it should be: - Has the contractor been conscientious to provide quality by carefully controlling materials and construction operations? - Has the contractor been proactive and made good use of QC data to maintain and improve quality? - Did the engineer provide the contractor with non-conforming test results within the contractual timeframe, if specified? - If timeframes are not specified, did the engineer provide non-conforming test results in time for the contractor to make process or materials corrections? - Upon becoming aware of a materials quality problem, has the contractor responded quickly to correct it? - Is the nonconforming test an isolated incident or a recurring situation? - How does the nonconforming test compare to the rest of the project data: - Have material test results been well within specification requirements or consistently at the very limit of what is acceptable? - How many tests are nonconforming vs. how many tests have passed? - How far out of spec is the non-conforming test? Price Reductions Specified in the Contract with Administrative Items If price reductions are included in the specifications or special provisions for certain nonconforming items, the price reductions should be administered using the appropriate 800 series administrative items. Since the price reductions are included in the contract language, the engineer can add the 800 series items to the contract without going through the complete change order process. Approval by a DOT representative and contractor representative are not necessary, though it's good practice to communicate the changes to all parties. Further guidance on the 800 series administrative items is provided in CMM For payment of nonconforming items with associated administrative items, pay for the installed quantity and bid price of the work item under the original bid item. The pay reduction will be accounted for using the administrative item. Compute the price reduction by multiplying the quantity of nonconforming material by the original unit price and the percent price reduction. The pay units of all administrative items are DOL. Document all calculations, and pay for the (negative) total calculated price reduction as the pay quantity, with 1 dollar as the pay unit. Example 1 - Contractor placed total of 19,000 SY of Concrete Pavement 9 inch SY (12' x 500') is 1/8" - 1/2" under plan thickness - Standard spec directs to pay 80% contract price for this range (20% reduction) - Bid unit cost is $35/SY Using original bid item, pay 19,000 SY at $35/SY = $655,000 Compute price reduction = 670 SY x $35 x = -$4,690 Add the administrative item Nonconforming Thickness Pavement to the contract, with unit price of $1.00 Pay quantity of -$4,690 Net pay = $655,000 - $4,690 = $650,310 Paying for nonconforming items this way allows for clean tracking of as-built quantities. The use of May 2015 Page 3

98 Construction and Materials Manual Chapter 8 Section 45 Materials Testing, Sampling, Acceptance Materials Testing and Acceptance - General Wisconsin Department of Transportation Materials sampling and testing methods and documentation procedures prescribed in chapter 8 of the CMM are mobilized into the contract by standard spec and standard spec Acceptance Procedures, Documentation, and Reporting Documentation and reporting for materials acceptance is equal in importance to Item Record Account documentation. The basis of acceptance for contract materials is accomplished in several ways, depending on the material. The type of reporting and documentation is a function of the acceptance type. Materials test reporting and documentation is to be done using the WisDOT electronic Materials Tracking System (MTS). The MTS is a computerized filing and reporting system for construction materials tests and documents. All construction materials tested and inspected for WisDOT projects are reported on the MTS. The overall MTS has three basic components, the MTS (LAN/WAN attached), Materials Information Tracking System (MIT), and the Materials Tracking website. Region and central office laboratory personnel can enter data directly into the Oracle database via a Local Area Network (LAN) attachment provided through the MTS. The MIT is used for entering tests from the field. The engineer should follow these guidelines for material documentation: - Inspect all manufactured products as soon as possible after delivery. - Include all approved lists, certified sources, and pre-qualified products. - Record in the project record relevant inspection information. - Verify that products delivered match the certifications, approved list, etc. - Review all Certifications of Compliance and Certified Reports of Test and Analysis. - Reference all Certifications, shop inspection reports, and other external documents using the MTS/MIT prefix 900 report. All materials documentation and reporting must be completed and entered in the MTS no more than 60 working days after the work completion date. Manufactured products must be inspected at the job site as soon as possible after arrival for evidence of damage or noncompliance even though these materials are covered by prior inspection testing or certification. Those materials normally source inspected, but which arrive at the job without appropriate marking, indicating that they have been accepted at the source, must be field inspected or tested and the basis for acceptance must be documented in the inspector s diary Materials Testing and Acceptance Guide The Materials Testing and Acceptance Guide, CMM 8-50 details many of the sampling, testing, and documentation requirements for various materials. The instructions shown in this guide are recommended minimum requirements. In many cases, it may be appropriate to increase the frequency and scope of certain testing and acceptance activities in order to properly administer the materials specifications. In all cases, it is appropriate to closely observe produced materials for visual evidence of changes in quality and to then adjust testing frequencies, as required, to adequately evaluate their quality. Sampling and testing procedures of certain unique materials are described in the standard specs and other contract documents. The instructions in this guide are intended to supplement those in other contract documents E-Guide E-Guide is an automated system that produces condensed sampling, testing and documentation guidance for material requirements for a project. It generates the guidance in two basic ways. For the project bid items, the system automatically generates guidance. For non-standard special provision (SPV) items, the system requires manual input of the SPV material requirements contained in the project proposal. CMM 8-50 should be cross checked when an E-Guide is developed since it contains detailed information and it breaks material information out by type. The E-Guide system for developing a project specific sampling and testing guide is available at: The WisDOT project material coordinator shall prepare the E-Guide and provide a copy to the contractor's material coordinator. Consult the region materials engineer or region person responsible for construction July 2014 Page 1

99 CMM 8-45 Materials Testing and Acceptance - General materials for guidance when developing the E-Guide. The E-Guide does not supersede material requirements in the Standard Spec or the CMM. The contractor is contractually bound to supply the information if required in the Standard Spec, CMM or Special Provisions. The region materials engineer or region person responsible for this area must be consulted regarding doubts as to the adequacy of compliance of source inspected materials, need for field inspection and reports, waiver of testing, unlisted items, evaluation of certifications, or other questions regarding acceptance procedures. Table 1 below defines the general documentation requirements for each materials acceptance type. Table 2 provides the MTS prefixes for all material types. Figure 1, Figure 2, and Figure 3 show example test reports. July 2014 Page 2

100 CMM 8-45 Materials Testing and Acceptance - General Table 1 Documentation Requirements for Different Acceptance Types Documentation Required Acceptance Type MIT/MTS Document MTS Documentation Time Line Remarks MTS Report. Verification tests- C.O. Laboratory Various MTS prefixes as appropriate. See Table 2 for a list of prefixes. No later than one week after completion of test. Test entry by C.O. Lab personnel. Materials Diary entry MTS reference report. Approved Product Lists- WisDOT Reference on MTS prefix 900 or 155 No later than 60 days after contract work completion date. Test entry by project personnel. Form DT 1823, Report of Shop Inspection. MTS reference report. Materials Diary entry. Source or Shop Inspection Reference on MTS prefix 900 or 155 No later than 60 days after contract work completion date. Test entry by project personnel. Source sampled materials tested and reported by C.O. personnel (see verification tests C.O. Lab above). Cert. of Compliance MTS reference report. Materials Diary entry. Manufacturers Certification of Compliance Reference on MTS prefix 900 or 155 No later than 60 days after contract work completion date. See note below [1]. Cert. Report of Test MTS reference report. Materials Diary entry Certified Report of Test Reference on MTS prefix 900 or 155 No later than 60 days after contract work completion date. See note below [1]. Verification tests-mts Report. Field Sampling and Testing Aggregates- MTS prefix 162, 217 HMA- MTS prefix 254 HMA Nuclear Density- MTS prefix 262 Concrete Cylinders MTS prefix 130 Earth Work Density- MTS prefix 232 No later than one week after completion of test. All aggregate and HMA QV testing done must be entered by the qualified lab doing the testing. When QV and Companion Cylinder testing is done the data must be entered by the qualified laboratory doing the testing. Quality Management Program (QMP) Quality Control (QC) tests. MTS Report. MRS Report (Structures Masonry Data)- contractor entry. MRS Report (IRI ride data) contractor entry. Field Sampling and Testing MTS Report 155 No later than 60 days after contract work completion dateprefix 155 data. MRS data is to be input by the contractor as it is developed. Refer to Figure 1, Figure 2, and Figure 3 for examples of prefix 155 reports for verification of contractor QMP and QC testing. [1] Certifications must be evaluated promptly for adequacy, completeness, and compliance with the specifications. The certification reviewer must make appropriate notations, initial, and date the document when the review is completed. July 2014 Page 3

101 TOPIC G: Asphalt Mixing Plants

102 TOPIC G: Asphalt Mixing Plants Page G-2 An HMA-TPC Technician should know the basic functions of a batch and drum mix facility operation. While conducting troubleshooting visits at the batch or drum mix facilities, the asphalt plant foreman should be notified by the HMA-TPC Technician of any problems that could be associated with the asphaltic mixture. The plant foreman has been trained to know almost every specific detail of the asphalt plant operation. Always work with the plant foreman on problems. Let him/her handle adjustments, check-ups, repairs and tuning. Again, remember to work out problems as a team. Please reference the Hot Mix Paving Handbook, Section 5

103 TOPIC G: Asphalt Mixing Plants Page G-3 Exercises on Asphalt Mixing Plants 1. How is the AC measured with a batch plant? 2. Where is the AC and hot aggregate mixed together in a batch plant? 3. How is the AC measured with a drum plant? 4. Where is the AC added in a drum plant?

104 TOPIC H: Process Control of Asphaltic Mixtures

105 TOPIC H: Process Control of Asphaltic Mixtures Page H-1 Process Control of Asphaltic Mixtures The HMA-TPC Technician is faced with two available options to begin troubleshooting an asphalt mixing plant. First of all, the asphalt mixture consists of aggregates, asphalt cement, and air voids. The process control of an asphalt mixing plant is divided into two types of problems: Aggregate gradation Asphalt content Aggregate Gradation Let s discuss aggregate gradation for a moment. examined carefully: There are three areas which need to be Stockpiles Stockpiles can be checked by analyzing the process control data from the stockpile as it was built or by sampling and testing the stockpile to obtain the gradation data. Cold feed A cold feed belt sample may be taken somewhere between the cold feed bins and the rotating drum/dryer for aggregate gradation determination. Extraction An extraction may be taken from the plant-produced asphaltic mixture to determine aggregate gradation. The extraction procedure should be performed by WisDOT method The extraction gradation is of most importance because it relates to the end product. Once the gradation data has been collected from the stockpile, cold feed, and extraction by WisDOT 1560, the data can be analyzed as follows: Stockpile vs. Cold Feed Gradation Data Each stockpile gradation can be mathematically blended to identify the appropriate JMF. Once the JMF has been established in the stockpiles, then the JMF blend may be compared to the cold feed gradations. At this point, you may be able to identify a problem that may be affecting the asphaltic mixture, such as segregation, degradation, improper load-out, etc. Cold Feed vs. Extraction Gradation Data During a process control troubleshooting inspection, the cold feed sample of the blended aggregates should be sampled simultaneously with the plant-produced asphaltic mixture. Usually it is advisable to wait one hour after sampling the cold feed blended sample before sampling the asphalt extraction sample. Once the samples have been procured simultaneously, the aggregate gradations may be used to determine a correlation between the aggregate test data. For instance, you may notice a higher percentage fines in the extraction sample. Excessive fines in the extraction gradation could indicate:

106 TOPIC H: Process Control of Asphaltic Mixtures Page H-2 Degradation in rotating dryer/drum High input of mineral filler (if applicable) High input of baghouse dust Aggregate problem (too soft) Bin spillover in No. 8 chip bin Segregation Contamination Change of stockpile material Asphalt Content Process control problems may also be associated with the asphalt content in an asphaltic mixture. Sources of asphalt content information are developed from: Calculations using G mm Nuclear gauge (optional) Nuclear Gauge The alternate method for determining the asphalt content is by nuclear gauge (optional method). Nuclear gauges are very expensive but produce very reliable results when properly calibrated.

107 TOPIC H: Process Control of Asphaltic Mixtures Page H-3 Significance of Gradation and Asphalt Content Gradation can affect: 1. Individual Sieve Percent Passing Each sieve percent passing must meet the specified JMF tolerances. As an HMA- TPC Technician, you may encounter a stockpile that has been depleted. The material supplier would like to deliver material from a pit two miles away which has a very similar gradation analysis. CAUTION: Even though the material has a similar gradation analysis, use of the material will probably result in a change of asphaltic mixture properties. The asphaltic mixture properties will be affected by: a. Change in crushing manufacturing process b. Change in particle shape VMA is affected by particle shape. c. Change in effective specific gravity, GSE A moderate change in the GSE value may indicate a material source change. 2. Test Results a. Bulk Specific Gravity, Gmb As the gradation moves away from the Maximum Density Line (MDL) Gmb decreases due to increased VMA. Inversely as gradation approaches the Maximum Density Line Gmb increases. b. Theoretical Maximum Specific Gravity, Gmm Gmm can be affected by gradation changes since different size elements in a blend may have significantly different Gsb. This is the reason we recalculate blended Gsb when aggregate blend percentage have been adjusted. 3. Volumetric Properties a. Voids in Mineral Aggregate, VMA VMA is a function of gradation, particle shape and asphalt content. If asphalt content and particle shape remain constant, as the gradation approaches the MDL inter-granular space is reduced resulting in a lower calculated VMA. b. Voids in Total Mix, VA (Air Voids) Air voids are defined as the VMA of compacted mixture that is not filled with asphalt. If asphalt content remains constant and VMA falls due to a change in gradation air voids will be reduced as well. 4. Performance Asphaltic Concrete performance can be affected by changes in gradation. Gradation changes that lead to high voids can cause the mix to be difficult to compact, high in place air voids allow the mix to remain permeable and the

108 TOPIC H: Process Control of Asphaltic Mixtures Page H-4 asphalt to age prematurely. High voids also contribute to rutting. Low voids can lead to excessive asphalt content and mixture that ruts or flushes.

109 TOPIC H: Process Control of Asphaltic Mixtures Page H-5 Asphalt content can affect: 1. Individual Sieve Percent Passing Asphalt content changes that are not accounted for when performing extraction using WisDOT 1560 can skew gradation calculations. Most notably the percent P#200 and a decrease in Asphalt content may be misinterpreted as a decrease in P# Test Results a. Bulk Specific Gravity, Gmb As asphalt content increases, Gmb increases; inversely, as asphalt content decreases, Gmb decreases. b. Theoretical Maximum Specific Gravity, Gmm As asphalt content increases, then Gmm decreases: inversely, as asphalt content decreases, the Gmm increases. 3. Asphalt content will affect mixture characteristics by: a. Voids in Total Mixture, VTM A decrease in asphalt content, means an increase in air voids; inversely, an increase in asphalt content means a decrease in air voids. b. Voids in Mineral Aggregate, VMA With an increase in asphalt content, VMA decreases to a point and then as more asphalt is added VMA can increase. VMA decreases initially as asphalt is added due to reduced friction between the aggregate particles. Once the volume of asphalt exceeds the volume of the voids in the mineral structure the asphalt crowds out aggregate and VMA will appear to increase. c. Performance Performance relies heavily on the percent air voids in the mixture and asphalt film thickness on the aggregate. Excessive in place air voids accelerates aging of the asphaltic mixture, leading to fatigue cracking. High voids can also be a contributing factor in pavement rutting. Proper asphalt content allows the mixture to be compacted readily in place, reducing the incidence of rutting and reducing the infiltration of air and water which can lead to loss of flexibility and adhesion of the binder. Over asphalting a mixture typically leads to low stability of the mixture and mixtures that will rut, shove and bleed under.

110 TOPIC H: Process Control of Asphaltic Mixtures Page H-6 Exercises Involving Process Control of Asphaltic Mixtures Sources of Possible Problems in a Batch Mix Facility 1. Cold Feed Bin Spillover 2. Incorrect Calibration Percentage for Each Cold Feed Bin 3. Finer Material Sticking to Cold Feed Bin Gates 4. Cold Feed Bins Run Empty 5. Moisture Content of Aggregate Stockpile Aggregate material flows differently as moisture increases or decreases in stockpiles. For instance, a plant is calibrated with the material at 1.5 percent moisture content. During the night, three to four inches of rain fall. Stockpile samples should be taken and new aggregate moistures determined. The new moisture content of the same aggregate material is at 5.5 percent. The material will flow differently at a rate of 5.5 percent moisture content. The higher percent moisture content will influence the flow rate of the finer material the most. 6. Slippage of Conveyor Belts Belts may loosen and cause feed problems. 7. Computer Control The environment of an asphalt plant is less than ideal for computer operation, dust, humidity, temperature variations, vibration and voltage fluctuation can all affect computer function. Errors can also occur in the entry of production parameters as well and should be considered. 8. Aggregate Scales Aggregate scales should be calibrated on the mixing platforms regularly. Scale zero should be noted daily as failure to return to zero can indicate several issues, failing load cells, blocked scales, etc. 9. Segregation Segregation is caused by improper load-out techniques, non-uniform feed on conveyor belts, change in moisture content levels of material and during unloading from silos, pugmills, trucks and pavers. 10. Sampling and Testing Errors These errors occur because of a failure to follow proscribed laboratory procedures, and temperatures. Double check all equipment and temperatures before making adjustments to the production process. Occasionally data entry and calculation errors can be misleading, use extreme care when entering test data.

111 TOPIC H: Process Control of Asphaltic Mixtures Page H-7 Sources of Possible Problems in a Drum Plant Sources of Possible Problems in a Batch Mix Facility 1. Cold Feed Bin Spillover 2. Incorrect Calibration Percentage for Each Cold Feed Bin 3. Finer Material Sticking to Cold Feed Bin Gates 4. Cold Feed Bins Run Empty 5. Moisture Content of Aggregate Stockpile As noted above aggregate flow rates can be affected by the moisture content of the aggregate. In the case of a drum mix plant moisture changes can also influence asphalt content if the change is not compensated for in the mix control system. 6. Slippage of Conveyor Belts Belts may loosen and cause feed problems. 7. Computer Control The environment of an asphalt plant is less than ideal for computer operation, dust, humidity, temperature variations, vibration and voltage fluctuation can all affect computer function. Errors can also occur in the entry of production parameters as well and should be considered. 8. Aggregate Scales Aggregate scales should be calibrated on the mixing platforms regularly. Scale zero should be noted daily as failure to return to zero can indicate several issues, failing load cells, blocked scales, etc. Asphalt is metered according to the aggregate weight from the belt scale, improper scale readings will lead to improper asphalt content. 9. Asphalt meters Improper calibration of the asphalt meter causes the mix to be over or under asphalted. Signal wires from the meter to the blending system can be distorted by improper shielding of the cord from sources of electromagnetic interference. 10. Segregation

112 TOPIC H: Process Control of Asphaltic Mixtures Page H-8 Segregation is caused by improper load-out techniques, non-uniform feed on conveyor belts, change in moisture content levels of material and during unloading from silos, pugmills, trucks and pavers. 11. Sampling and Testing Errors These errors can occur because of a failure to follow proscribed laboratory procedures, and temperatures. Double check all equipment and temperatures before making adjustments to the production process. Occasionally data entry and calculation errors can be misleading, use extreme care when entering test data.

113 TOPIC H: Process Control of Asphaltic Mixtures Page H-9 Problems Associated with Aggregate Many problems associated with aggregates can be minimized by careful attention to handling and stockpiling the aggregates during production. It is a good idea before project start-up to know the method(s) of stockpile construction. Review the quality control/quality assurance data to discover how uniformly each stockpile has been built. A stockpile built with no process control or test records may indicate a non-uniformly built stockpile. Additional sampling and testing may be required by the quality control team to verify uniformity. Stockpiles built in layers will help minimize segregation. The load out is another possible source of variability, whenever possible the loader should work perpendicular to the direction of flow for the stacking conveyor. The loader should work the entire face to minimize segregation. The cold feed system is responsible for metering the aggregates into the plant in the proper percentages. Care must be taken to calibrate the bins accurately so that the desired blend is achieved. Cold feed calibration is accomplished in two ways: 1. Gates Gates are used to restrict the opening of the bin. The gates should be adjustable and durable enough to maintain the desired opening. Once set it is helpful to mark the gate in some way so that if it is moved for maintenance it will be possible to return it to near the original setting to speed recalibration. 2. Variable Speed Feeder Belts After the gate opening has been selected, based on the approximate percentage of the material desired from the individual bin, the feeder belt is run at speeds from maximum to minimum operational range. The rate of material delivered at each speed is determined and can be entered into the control system so that the proper amount of each aggregate is delivered into the drum.

114 TOPIC H: Process Control of Asphaltic Mixtures Page H-10 Factors or Causes Attributed to Aggregate Problems 1. Segregation This can occur at any time or anywhere on and off the project site. Try to minimize segregation by handling material properly. 2. Degradation This occurs as larger material breaks down into smaller sizes. Control degradation by alerting heavy equipment operators to stay off stockpiles or keep traffic minimal, if possible. Some degradation will occur in the mixing process and is unavoidable. 3. Contamination This usually occurs when the loader operator digs down too deep into the stockpile, carrying foreign material on tires onto stockpile and during cold feed bin spillover. 4. Improper Loading of Cold Feed Bins This consists of improper load-out procedure, loading of wrong material into cold feed bin(s), or loading causing bin spillover. 5. Gate/Flow Rate Feeder Calibration Be alert to changing moisture conditions in stockpiles. It is advisable to conduct percent aggregate moisture tests (AASHTO T-255 Standard Method of Test for Total Moisture Content of Aggregate by Drying) to monitor the percent moisture content in each stockpile. Remember, moisture content mainly affects finer aggregate stockpiles. 6. Moisture Excessive moisture causes problems with gate/flow rate feeder calibrations and also affects the drying time in the drum/dryer and the production rate (tons per hour). Improperly-dried aggregates during the drum/dryer process are attributable causes to the stripping and raveling problems associated with the asphaltic mixture. Factors Attributed to Production (Plant) Problems The responsibility of an HMA-TPC Technician is not to know every aspect of how asphalt mix facilities function but to be aware of problems which might exist. The responsibility of the HMT-TPC Technician involves communication with the QC team to resolve process control problems. Again, always work with the plant foreman in solving production (plant) problems. DO NOT repair or make any physical adjustments yourself.

115 TOPIC H: Process Control of Asphaltic Mixtures Page H-11 Let s discuss some common production (plant) problems: 1. Equipment Wear Batch Plant Screens, chutes, and bins in the hot tower. Batch/Drum Worn Flights inside the dryer/drum can lead to improper mixing, poor heat transfer, and poor drying of aggregate. 2. Equipment Malfunction Drum Plant The weigh scale on the conveyor belt does not operate correctly if the conveyor belt slips, so be aware! Load Cell A load cell is a device used in the weighing process. Improper aggregate/asphalt weights before the mixing process will cause process control problems. 3. Electronics Lightning High towers at asphalt plants are prime candidates for lightning strikes. Lightning strikes have affected the operation of the computer. Make sure all towers have been properly grounded. Causes Attributed to Production (Plant) Problems: 1. Poor Maintenance Proper preventive maintenance of equipment may prevent equipment plant problems. Regular inspection and effective communication of observed potential problems is fundamental to a solid preventative maintenance program. 2. Lack of Proper Control Poor communication of sample data makes it impossible to respond to issues as they arise. Failure to respond to problems in a timely fashion can make major issues out of minor deviations. 3. Lack of Understanding Keep all team members informed of specifications and penalties assessed for not complying with specification requirements. A misinformed or confused team member could be a process control problem. The key word is team.

116 TOPIC H: Process Control of Asphaltic Mixtures Page H-12 Factors Attributed to Equipment-Related Problems: 1. Causes in Batch Plant a. Aggregate Scales If the weight of the aggregate varies up or down, this phenomenon will affect the percent asphalt content. The plant foreman should check aggregate scales calibration regularly. b. AC Scales Regularly calibrate AC scale and check asphalt weight bucket to make sure it moves freely. c. Leaking Valves A common process control problem is caused by a leaky or clogged asphalt valve or line. 2. Causes in Drum Mix Facility a. Aggregate Belt Scales Aggregate belt scales may be out of adjustment or slipping, and excess fine material buildup may affect the weigh scale capability. Excess buildup on the belt is attributed to moisture conditions. Both of these conditions will overestimate aggregate quantities. b. Asphalt Meter Calibration The asphalt meter is calibrated by pumping a certain amount of asphalt into a tanker and then weighing the tanker and recording the asphalt cement temperature. Improper temperatures or binder specific gravity will affect asphalt content. Be aware: some asphalt flow meters will measure air as asphalt. For example, at the end of a project, a plant foreman would like to empty the asphalt storage unit so that he/she does not have to pump out the asphalt cement. While trying to empty the asphalt storage unit, the foreman may inadvertently measure air near the bottom of the unit, and false readings in measuring may occur. c. Incorrect Moisture Correction It is very important to monitor the actual moisture content (AASH90 T 255- Total Moisture Content of Aggregate by Drying). It is critical that the actual moisture correction factor be dialed into the plant computer. Improper moisture correction factor will cause process control problems with asphalt content and affect the asphaltic mixture properties. If the moisture content is too high and adjustments have not been made on the scale, then a portion of that water will appear as aggregates. This condition will produce low total voids in the mixture (high AC). Inversely, if the moisture content is estimated, this will reduce the quantity of asphalt added, and the voids in the total mixture will increase (low AC).

117 TOPIC H: Process Control of Asphaltic Mixtures Page H Problems Common to All Plants a. Wrong Type of Asphalt Cement The specific gravity of the different types of AC will change and have a direct effect on the asphaltic mixture properties. b. Mixture Temperature If you witness blue smoke from an asphaltic mixture, the mix temperature is too high. Also, too high an asphalt mix temperature will burn off and reduce the asphalt film thickness. The asphalt film thickness affects the performance life of the asphalt mixture. Low asphalt mix temperature will affect coating of the aggregate particle and reduce the ability to achieve proper compaction causing poor pavement performance. c. Electronics d. Sampling and Testing Aggregate Diagnostic Problems Gradation a. If individual sieve is off specifications: o Check Control Charts for Mixture Properties For example: Air Voids o If air voids within limits, adjust tolerance for individual sieve and ask for JMF change. o If air voids outside limits, look for causes. b. Causes of off tolerance gradation o Cold feed gradation (stockpile/belt) o Moisture in fine aggregates o Equipment wear o Flow rate/scales o Sampling and testing

118 TOPIC H: Process Control of Asphaltic Mixtures Page H-14 Gradation Variabilities Checklist 1. Aggregate Stockpiling New added material Changes at source Segregation during hauling or stockpiling Sampling and testing errors 2. Belt Samples Variation in stockpiling Segregation of aggregate Improper loading of cold feed bins Improper setting of individual cold feed bins Sampling and testing errors 3. Hot Bins Improper cold feed setting Erratic feed from dust-collecting system Changing production rate (screening efficiency) Blinding screens Holes in screen or bin walls Sampling and testing errors 4. Asphaltic Mixtures Sample location Truck Back of paver Causes of variability Incorrect hot bin gradations Incorrect percentages Segregation in truck or silo

119 TOPIC H: Process Control of Asphaltic Mixtures Page H-15 Mixture Diagnostic Problems 1. Total Mixture Voids - Air Voids, % 2. Low Air Voids 3. High Air Voids Most important physical property If too high -- If too low -- Causes Gradation P-200 High asphalt content Corrections Check gradation Check P-200 Check asphalt metering/scales Causes Incorrect moisture content Segregation Incorrect asphalt content Corrections Compare actual and used moisture contents Check gradation -- perform extraction Calculate percent AC and/or check metering/scales Change In Maximum Specific Gravity, Gmb, Indicates 1. Asphalt content 2. Aggregate gradation 3. Specific gravity 4. Absorption 5. Sampling and testing

120 TOPIC H: Process Control of Asphaltic Mixtures Page H-16 Process Control Problem Solving Using A Flow Chart Process control problem solving using a flow chart can be a very useful trouble-shooting tool. A flow chart is a methodical approach, which organizes the way to handle or solve a problem. QC Data approaching warning band No Are Va and Vma Acceptable? Yes Has Gmm changed? No Is Gradation Acceptable? Yes Yes Yes No Moisture change? Correct. Yes No No Yes No No No Are Agg Scales functioning properly? Yes Is asphalt usage correct? Recalibrate meter or Weigh Pot. Has Gmb Changed? Yes OK Check Calculations. Check agg Gravities Absorption FAA CAA Yes Has source changed? Batch or Drum Plant? New Crushing? Drum Batch Check Stockpile Gradations, Gate Settings Blend % s Bin per agg Check Stockpile Gradations, Gate Settings Blend % s Bin per agg Hot draws Hot bin gradation Hot Screens

121 TOPIC H: Process Control of Asphaltic Mixtures Page H-17 Exercise on Asphalt Mixing Facility 1. Who is responsible for making asphaltic mix adjustments at the asphalt mixing plant?

122 TOPIC I: Troubleshooting Mixtures, Sampling and Testing, and Asphalt Problems

123 TOPIC I: Troubleshooting Mixtures, Sampling & Testing Page I-1 Sampling and Testing Errors in Aggregate 1. Improper Conveyor Belt Sample Technique For example, a certified AGGTEC-I may be sampling off the stopped conveyor belt and be using a paint scraper to remove all fine material which has built up on the conveyor belt over time. The excess fine material scraped from the conveyor belt may have been the leading cause of the process control problem. The sampling problem will be solved by communicating to the certified AGGTEC-I to observe the underside of the belt and use only a fine brush to remove material from the conveyor belt. 2. Improper Test Sample Size Check to make sure aggregate samples have been procured by using the specified nominal maximum particle size definition. Refer to WisDOT Sample Size By Nominal Maximum Particle Size (CMM ). 3. Overloading of Sieves on Gradation Analysis Overloading of a sieve will cause a gradation test analysis to be unacceptable. Each sieve must conform to the specified maximum allowable weight. Refer to WisDOT Maximum Weight of Material Allowed on Sieves (CMM ). 4. Improper Gradation Analysis Calculation Always double-check calculations before alerting anyone of any process control problems. Sometimes a miscalculation may be all that is wrong. 5. Calibration and Condition of Scales Always check weigh scales periodically. A weigh scale may be checked by using a calibration weight. 6. Improper Riffle Splitting Technique A rectangular sampling receptacle shall be used to feed the sample through the riffle splitter. A riffle splitter shall be clean and free of particles which may contaminate the sample. 7. Not Adhering to Prescribed Sampling and Testing Procedures Short cuts or unapproved sampling and testing methods are violations of the specifications. Sampling and testing methods must be conducted by the prescribed procedure(s) which conform with project specifications.

124 TOPIC I: Troubleshooting Mixtures, Sampling & Testing Page I-2 Sampling and Testing Problems Associated with Asphaltic Mixtures 1. Sampling Errors Obtaining incorrect sample sizes is the most common sampling error. Always check to make sure at least the minimum specified sample weights have been procured. Also, improper quartering technique may induce segregation into the asphalt mixture. It is vitally important that all asphaltic mixture samples have been properly prepared and are stored in a dry area for the specified time period. Improperly stored and prepared retained samples will affect the results of the quality verification (QV) team. 2. Equipment Calibration a. Theoretical Maximum Specific Gravity (Gmm) Apparatus First, make sure oil level is okay and change oil whenever oil appears a milkywhite color, usually about every three days. Second, air leaks in system hoses, hose connections, and leaky valves will cause improper vacuum. Third, check manometer to make sure there are no air gaps in the level of mercury. Fourth, the Gmm apparatus should be calibrated periodically. Finally, check to see if there is a screen over the pycnometer vacuum connection. This screen will aid in preventing material from being trapped in the vacuum lines. b. Scales Most electronic balances are heat sensitive, and a balance may weigh differently if exposed to a range of temperatures. Sometimes electronic balances drift, not weighing the same every time. Scale calibration should be performed periodically at least once before project start-up. Use certified standard calibration weights for calibration. Certified standard calibration weights should be checked annually. Certified calibration weights should be handled with special gloves that come with the weights. If you use your fingers to handle the certified calibration weights, oil residue from your fingers will allow the calibration weight to pick up dust or material particles and affect calibration. c. Temperature Most problems in testing can be related to temperature. Calibration shall include thermometers and ovens. Also, check waterbaths to make sure they conform to the specified temperatures, and check circulating pumps to ensure they are providing uniform water temperatures.

125 TOPIC I: Troubleshooting Mixtures, Sampling & Testing Page I-3 3. Calculation Error Always double-check your calculations. It is a good idea to have someone else check your work as well. Never alert anyone to a process control problem until all calculations have been rechecked. Remember, whenever equipment is calibrated, make sure it is documented, posted, and part of the project records. Factors Affecting Maximum Specific Gravity, Gmm 1. Increase in asphalt content 2. Aggregate gradations 3. Specific gravity/absorption of aggregates Exceeding Allowable Differences On Test Results Differences between the contractor's and engineer's split sample test results will be considered acceptable if within the following limits: Item Allowable Differences Sieve - percent passing 12.5 mm mm mm mm μm μm 2.0 Bulk Specific Gravity of the compacted mixture Maximum Specific Gravity 0.020

126 TOPIC I: Troubleshooting Mixtures, Sampling & Testing Page I-4 If comparison test results are outside the above allowable differences, the engineer will investigate the reason immediately. The engineer may stop production while the investigation is in progress if the potential for a pavement failure is present. The engineer's investigation may include testing of the remaining split samples, review and observation of the contractor's testing procedures and equipment, and a comparison of split sample test results by the contractor quality control laboratory, WisDOT quality verification laboratory, and the Bureau of Technical Services. If reasons for the differences cannot be determined, the engineer's results will be used for the quality control data, and the appropriate payment for the mixture and asphalt will be based on the procedures specified. The engineer will periodically witness the sampling and testing being performed by the contractor. If the engineer observes that the sampling and quality control tests are not being performed in accordance with the applicable test procedures, the engineer may stop production until corrective action is taken. The engineer will notify the contractor of observed deficiencies promptly, both verbally and in writing. The engineer will document all witnessed sampling and testing. If a difference exists between the contractor and the engineer, the Bureau of Technical Services will be asked to advise on the proper sampling and testing procedure. Calculations Using Theoretical Maximum Specific Gravity, Gmm As per WisDOT specifications, calculation of asphalt content begins on the second day of production. Asphalt content is calculated from the mixture Gmm, AC sp. Gr. 77/77F and GSE (Asphalt content shall be calculated and reported to two decimal places.) Determination of aggregate specific gravity, GSE, is the volume of the aggregates including all the aggregate internal void spaces except those that absorb asphalt. Calculations of GSE: GSE - (100 - % AC) / [(100 / Gmm) - (%AC / AC Sp. Gr.)] Where: % AC = Tank sticking at end of day s production AS Sp. Gr. = From the mix design Gmm = Daily average

127 TOPIC J: Process Control Relationships

128 TOPIC J: Process Control Relationships Page J-1 Control Charts The control chart is a visual aid used to measure the variability of a process. Today, most agencies specify color codes and assign values to specify the desired quality parameters. As an HMA-TCP Technician, you must possess the skills to analyze and interpret data by examining control chart trend relationships. Shown below is a model of a control chart: Upper Control Limit (UCL) Upper Warning Band Upper Warning Limit (UWL) Target Lower Warning Limit (LWL) Lower Warning Band Lower Control Limit (LCL) Specifications state the test results obtained by the contractor shall be recorded on the control charts the same day the tests are conducted. It is very important so that trends may be analyzed as soon as process control data become available. Gradation Master Band The HMA-TPC Technician s occupational responsibility is to monitor, analyze, and make necessary asphaltic mixture adjustments to satisfy the parameters of the specifications. As long as trends are between the JMF and warning limits, no significant changes or adjustments are required. Before any necessary process control adjustments are to be made, make sure all data have been thoroughly analyzed. Job mix formula (JMF) adjustment may be necessary on the No. 8 sieve. The JMF limits for a 12.5 mm mixture on the No. 8 sieve are between 28 and 58 percent passing. The current No. 8 sieve running average is at 58 percent. The new JMF limit shall not exceed the gradation master band of either 28 or 58 percent. However, the JMF tolerances may exceed the gradation master and. The new JMF limit target is at 58 percent. Refer to Figure 9.1 Gradation Master Band illustration UCL UWL New JMF Target = 58% 58.0 Target LWL LCL Figure Gradation Master Band Illustration

129 TOPIC J: Process Control Relationships Page J-2 Documentation WisDOT standard specification states, The contractor shall be responsible for documenting all observations and records of inspection, adjustments to the mixture, and test results on a daily basis. Results of observations and records of inspection shall be noted in a permanent field record as they occur. All process adjustments and job mix formula changes shall be noted on the air void chart. Copies of the running average calculation sheet for blended aggregate, mixture, and asphalt content along with the air void chart and records of adjustment shall be provided to the engineer in a neat and orderly manner within ten days after the completion of paving.@ Relationships of Asphaltic Mixture Properties Specific Gravity The voids in total mixture (VTM) is the most important asphaltic mixture property related to performance. Three common test procedures used for determining VTM: 1. Compaction of specimen, AASHTO T Bulk specific gravity of compacted bituminous paving mixtures using saturated surface-dry specimens, AASHTO T Rice maximum specific gravity of bituminous paving mixtures, AASHTO T 209 The bulk specific gravity (Gmb) is determined by AASHTO T 312 and AASHTO T 166. The Gmb consists of three ingredients: air, asphalt, and aggregate. Bulk Specific Gravity, Gmb A = B = C = Volume of air Volume of asphalt Volume of aggregate Gmb = A + B + C 115 mm +/-5 mm The Gmb specimen is 150 mm in diameter and 115 mm +/- 5mm in height. The Gmb is measuring the weight/volume relationship or specific gravity of each ingredient involved in the asphaltic mixture. In an examination of Gmb volume relationships, the aggregates are the most predominant factor and affect the results of the Gmb the most. The inverse is true regarding air and asphalt. Gmb equals volume of air plus volume of asphalt plus volume of aggregates. 150 mm A B C

130 TOPIC J: Process Control Relationships Page J-3 The theoretical maximum specific gravity (Gmm) is determined by the rice maximum specific gravity of bituminous paving mixture procedure, AASHTO T 209. The Gmm includes two ingredients: aggregates and asphalt. Theoretical Maximum Specific Gravity, Gmm B = Volume of asphalt C = Volume of aggregate A = Volume of air = 0 B C Gmm = B + C The Gmm measures the weight/volume relationship or specific gravity of the asphalt and aggregates in a voidless state. Again, aggregates are the predominant influence on the Gmm asphaltic mixture property. Gmm equals volume of aggregate plus volume of asphalt. The percent VTM is determined by the relationship of Gmm minus Gmb divided by Gmm % Voids = [(Gmm - Gmb) / Gmm ] x 100 multiplied by 100. The percent voids measures volume of air in the following: Compacted briquette (laboratory of field voids) Cores (roadway voids) Determination of percent density is Gmb divided by Gmm multiplied by 100. % Density = (Gmb/Gmm) x 100

131 TOPIC J: Process Control Relationships Page J-4 Asphaltic Mixture Property General Guidelines percent change in (-) P-200 material generally creates about a 1.0 percent change in voids. 2. Too much or not enough (-) P-200 material creates a tender asphaltic mixture. 3. A sandy mix (very fine on the No. 8 sieve) may create a tender asphaltic mixture. 4. Too high a percentage of material passing No. 30 sieve can create a tender asphaltic mixture (sand or camel hump). 5. Segregation of a sample can correlate to the asphalt content being high or low for an individual test. 6. Mat temperature for breakdown rolling should be 285 ± 15 o Fahrenheit. Finish rolling should occur at about 120 o Fahrenheit or cool enough to place your hand on the mat and leave it. Predetermined Proportionality Rules for Asphalt Mixture Properties Aggregate gradations trending down indicates coarser mixture. Aggregate gradations trending up indicates finer mixture. A coarser mixture relates to lower VMA. (Relative to max density line.) A finer mixture relates to higher VMA. (Relative to max density line.) Gmm (goes down) then % AC (goes up) Gmm (goes up) then % AC (goes down) Gmb (goes down) then % AC (goes down) Gmb (goes up) then % AC (goes up) If AC stays the same, gradation No. 8 to No. 200 (goes down) then VTM (goes down) If AC stays the same, gradation No. 8 to No. 200 (goes up) then VTM (goes up) Gmb (goes down) = AC (Constant) then P-200 (goes down) Gmb (goes up) = AC (Constant) then P-200 (goes up) Use caution. All proportionality rules are theoretically-based mathematical concepts. In reality, things may happen without justification of the proportionality rules.

132 TOPIC J: Process Control Relationships Page J-5 PROCESS CONTROL RELATIONSHIP EXERCISE A A trend on a control chart is the first visual indicator that a possible asphaltic mixture problem is occurring. Exercises A through D have been designed to demonstrate how the analysis of process control trends can be used to solve asphaltic mixture properties. 1. Refer to Figure 10.1, Process Control Relationship Exercise A. Identify all trends represented by the aggregate gradations and list below. 2. Refer to Figure , Process Control Relationship Exercise A. List and identify trends for each asphaltic mixture property; Gmb, Gmm, VMA, VTM, and % AC. Gmb Gmm VMA VTM % AC 3. What conclusions can be drawn from analyzing the trends from questions 1 and 2? Proportionality Rules Aggregate gradations trending down indicates coarse mixture. Aggregate gradations trending up indicates fine mixture. If Gmm (goes down) then % AC (goes up) If Gmm (goes up) then % AC (goes down) If Gmb (goes down) then % AC (goes down) If Gmb (goes up) then % AC (goes up)

133 TOPIC J: Process Control Relationships Page J-6 By analyzing the trends, you find: 4. What are the typical causes attributed to low asphalt content in a batch and drum plant? List causes common to both plants. Batch Plant: Drum Plant: Common to Both Plants:

134 TOPIC J: Process Control Relationships Page J-7 PROCESS CONTROL RELATIONSHIP EXERCISE A ANSWERS 1. Aggregate gradations are okay and within warning limits. 2. Gmb is trending down Gmm is trending up VMA is trending up VTM is trending up % AC is trending down 3. Aggregate gradation is okay, within warning limits Gmb is trending down (Gmb goes down = % AC goes down) Gmm is trending up (Gmm goes up = % AC goes down) % AC is trending down Conclusion: The Gmb, Gmm, VTM, and % AC trends indicate low % AC. The aggregate gradation is okay, within warning limits. All trends indicate low % asphalt content. 4. Batch Plant Aggregate scales AC scales Leaking valves or clogged line Drum Plant Aggregate belt scales Asphalt meter calibration Incorrect moisture correction Common to Both Plants Wrong type of AC Asphalt mixture temperature Electronics Sampling and testing (calculations)

135 TOPIC J: Process Control Relationships Page J-8 PROCESS CONTROL RELATIONSHIPS EXERCISE B 1. Refer to Figure 10.2, Exercise B - Process Control Relationships. Identify all trends represented by the aggregate gradations and list below: 2. Refer to Figure , Exercise B - Process Control Relationships. List and identify trends for each asphaltic mixture property: Gmb, Gmm, VMA, VTM, and % AC. Gmb Gmm VMA VTM % AC 3. What conclusions can be drawn from analyzing the trends from questions 1 and 2? Proportionality Rules Aggregate gradations trending down indicates coarse material. Aggregate gradations trending up indicates fine material. If Gmm (goes down) then % AC (goes up) If Gmm (goes up) then % AC (goes down) If Gmb (goes down) then % AC (goes down) If Gmb (goes up) then % AC (goes up)

136 TOPIC J: Process Control Relationships Page J-9 By carefully analyzing the trends, you find: 4. What are typical causes attributed to coarse aggregate being fed into a batch and drum plant? Batch Plant: Drum Plant:

137 TOPIC J: Process Control Relationships Page J-10 PROCESS CONTROL RELATIONSHIP EXERCISE B ANSWERS 1. All gradations are trending downward, which indicates a coarse mixture. (Refer to proportionality rules.) 2. Gmb is trending up Gmm is trending down VMA is trending down VTM is trending down % AC is okay 3. Aggregate gradation is trending coarser Gmb is trending up Gmm is trending down VMA is trending down VTM is trending down % AC is okay Conclusion: May indicate a change in aggregate source or a problem with sand in the cold feed bin. 4. Batch Plant: Improper load-out procedure Cold feed bin spillover (coarser aggregates in fine bin) Incorrect calibration/percentage for each cold feed bin Change in aggregate stockpile material Sand bin is near empty Wet material - change in flow rate Material sticking in gates Sampling and testing errors - calculations Visual inspection Drum Plant: Problems are similar to batch plant

138 TOPIC J: Process Control Relationships Page J-11 PROCESS CONTROL RELATIONSHIP EXERCISE C 1. Refer to Figure 10.3, Exercise C - Process Control Relationship. Identify all trends listed by the aggregate gradations and list below: 2. Refer to Figure , Exercise C - Process Control Relationship. List and identify trends for each asphaltic mixture property: Gmb, Gmm, VMA, VTM, and % AC. Gmb Gmm VMA VTM % AC 3. What conclusion can be drawn from analyzing the trends from questions 1 and 2? Proportionality Rules Aggregate gradations trending down indicates coarser material. Aggregate gradations trending up indicates finer material. The coarser the mixture, the lower VMA The finer the mixture, the higher VMA If Gmm (goes down) then % AC (goes up) If Gmm (goes up) then % AC (goes down) If Gmb (goes down) then % AC (goes down) If Gmb (goes up) then % AC (goes up) If AC stays the same, then gradation No. 8 - No. 200 (goes down) then VTM (goes down) If AC stays the same, then gradation No. 8 - No. 200 (goes up) then VTM (goes up) By carefully analyzing the trends, you find:

139 TOPIC J: Process Control Relationships Page J-12 PROCESS CONTROL RELATIONSHIP EXERCISE C ANSWERS mm (No. 4) and 2.36 mm (No. 8) gradations are trending downward indicating coarse material. 2. Gmb is trending down Gmm is trending down VMA is trending down VTM is trending down % AC is okay mm (No. 4) and 2.36 mm (No. 8) gradations are trending downward, indicating coarse material. Gmb is trending down Gmm is trending down VMA is trending down VTM is trending down % AC is okay Conclusion: VMA and VTM are within specification limits, and % AC is okay. A cold feed bin percentage change may be necessary to solve the coarse 4.75 mm (No. 4) and 2.36 mm (No. 8) material problem.

140 TOPIC J: Process Control Relationships Page J-13 PROCESS CONTROL RELATIONSHIP EXERCISE D - PART 1 1. Refer to Figure 10.4, Exercise D - Part 1 - Process Control Relationship. Identify all trends represented by the aggregate gradations and list below. 2. Refer to Figure , Exercise D - Part I - Process Control Relationship. List and identify trends for each asphaltic mixture property; Gmb, Gmm, VMA, VTM, and % AC. Gmb Gmm VMA VTM % AC 3. What possible conclusions can be drawn from analyzing the trends from questions 1 and 2? Carefully analyzing the trends, you find:

141 TOPIC J: Process Control Relationships Page J-14 PROCESS CONTROL RELATIONSHIP EXERCISE D - PART 1 ANSWERS 1. All gradations are trending upward, indicating a finer mixture. 2. Gmb is trending down Gmm is trending up VMA is trending up VTM is trending up % AC is trending down 3. Aggregate gradations are trending upward, indicating a finer mixture. Gmb is trending downward Gmm is trending upward VMA is trending upward VTM is trending upward % AC is trending downward Possible Conclusion: Exercise D - Part 1 indicates more than one solution may be needed to satisfy the asphalt mixture property parameters. During problem-solving determination, always try one method of adjustment to ensure you use the process of elimination to resolve a problem. Trying to solve a problem using multiple solutions will confuse the problem-solving process.

142 TOPIC J: Process Control Relationships Page J-15 PROCESS CONTROL RELATIONSHIP EXERCISE D - PART 2 1. Use the aggregate trends from Figure 10.4, Exercise D-Part 1 - Process Control Relationship. Use Figure , Exercise D-Part 2-Process Control Relationship to identify trends for each asphaltic mixture property: Gmb, Gmm, VMA, VTM, and % AC. Gmb Gmm VMA VTM % AC Possible Solution: PROCESS CONTROL RELATIONSHIP EXERCISE D-PART 2 ANSWERS 1. Gmb is trending downward Gmm is trending downward VMA is trending upward VTM is trending downward % AC is trending upward Possible Solution: VMA is trending high, VTM is trending very low, and % AC is trending really high. Adjusting the % AC should be the last alternative in solving an asphaltic mixture problem. The % AC in the mixture is necessary to facilitate a durable asphalt film thickness to instill pavement durability, although too much % AC in a mixture could cause bleeding and be detrimental to an asphaltic mixture. In this example, lowering the % AC may be the solution.

143 TOPIC K: Process Control Relationship Problems

144 TOPIC K: Process Control Relationship Problems Page K-1 PROBLEM # 1 - PROCESS CONTROL 1. Refer to Figures through , Problem #1 - Process Control. Identify all trends represented by the aggregate gradations and list below. 2. Refer to Figures through , Problem #1 - Process Control. List and identify trends for each asphaltic mixture property: Gmb, Gmm, VMA, VTM, and % AC. Gmb Gmm VMA VTM % AC 3. What conclusions can be drawn from analyzing the trends from questions 1 and 2? By analyzing the trends, you find: 4. What are the typical causes attributed to: Batch Plant: Drum Plant: Other:

145 TOPIC K: Process Control Relationship Problems Page K-2 PROBLEM # 2 - PROCESS CONTROL 1. Refer to Figures through , Problem #2 - Process Control. Identify all trends represented by the aggregate gradations and list below. 2. Refer to Figures through , Problem #2 - Process Control. List and identify trends for each asphaltic mixture property: Gmb, Gmm, VMA, VTM, and % AC. Gmb Gmm VMA VTM % AC 3. What conclusions can be drawn from analyzing the trends from questions 1 and 2? By analyzing the trends, you find: 4. What are the typical causes attributed to: Batch Plant: Drum Plant: Other:

146 TOPIC K: Process Control Relationship Problems Page K-3 PROBLEM #3 PROCESS CONTROL 1. Refer to Figures through , Problem #3 - Process Control. Identify all trends represented by the aggregate gradations and list below. 2. Refer to Figures through , Problem #3 - Process Control. List and identify trends for each asphaltic mixture property: Gmb, Gmm, VMA, VTM, and % AC. Gmb Gmm VMA VTM % AC 3. What conclusions can be drawn from analyzing the trends from questions 1 and 2? By analyzing the trends, you find: 4. What are the typical causes attributed to: Batch Plant: Drum Plant: Other:

147 TOPIC K: Process Control Relationship Problems Page K-4 PROBLEM # 4 - PROCESS CONTROL 1. Refer to Figures through , Problem #4 - Process Control. Identify all trends represented by the aggregate gradations and list below. 2. Refer to Figures through , Problem #4 - Process Control. List and identify trends for each asphaltic mixture property: Gmb, Gmm, VMA, VTM, and % AC. Gmb Gmm VMA VTM % AC 3. What conclusions can be drawn from analyzing the trends from questions 1 and 2? By analyzing the trends, you find: 4. What are the typical causes attributed to: Batch Plant: Drum Plant: Other:

148 TOPIC K: Process Control Relationship Problems Page K-5 PROBLEM # 5 - PROCESS CONTROL 1. Refer to Figures through , Problem #5 - Process Control. Identify all trends represented by the aggregate gradations and list below. 2. Refer to Figures through , Problem #5 - Process Control. List and identify trends for each asphaltic mixture property: Gmb, Gmm, VMA, VTM, and % AC. Gmb Gmm VMA VTM % AC 3. What conclusions can be drawn from analyzing the trends from questions 1 and 2? By analyzing the trends, you find: 4. What are the typical causes attributed to: Batch Plant: Drum Plant: Other:

149 TOPIC K: Process Control Relationship Problems Page K-6 PROBLEM # 6 - PROCESS CONTROL 1. Refer to Figures through , Problem #6 - Process Control. Identify all trends represented by the aggregate gradations and list below. 2. Refer to Figures through , Problem #6 - Process Control. List and identify trends for each asphaltic mixture property: Gmb, Gmm, VMA, VTM, and % AC. Gmb Gmm VMA VTM % AC 3. What conclusions can be drawn from analyzing the trends from questions 1 and 2? By analyzing the trends, you find: 4. What are the typical causes attributed to: Batch Plant: Drum Plant: Other:

150 APPENDIX 1: Answers to Student Problems WisDOT Test Method No. 1559

151 Appendix 1: Answers to Student Problems Page 1-1 TOPIC: Standard Specifications 1. WisDOT Standard Specifications 2. In what instances is the contractor required to stop mixture production? When two consecutive running average values exceed the warning limit 3. What payment reduction percentage is applied to air voids produced within the warning bands? Pay is at 70%m of contract price WisDOT Standard Specifications 1. What is the maximum percentage wear loss at 500 revolutions for an E-3 mixture? 45% 2. What is the minimum FAA requirement for an E-10 mixture? What is the minimum percent VMA for a 12.5mm mixture? 14.0% (may be changing)

152 Appendix 1: Answers to Student Problems Page 1-2 Asphaltic Mix Design 1. What are the most important factors in predicting asphaltic mixture performance? Percent Air Voids and Compaction 2. What should the in-place air voids be for an E-10 mixture? 92.0% of the target maximum density 3. Air voids between and % after two to three years of traffic loading will provide optimum pavement performance. 3% and 5% 4. The higher the FAA, the higher the is. The higher the voids between the fine aggregate particles. The higher the void content, the more angular the fine aggregate is. Asphalt Mixing Plants 1. How is the AC measured with a batch plant? Based on the aggregate batch size setting (2-6 ton) and pumped to a separate heated weigh bucket. 2. Where is the AC and hot aggregate mixed together in a batch plant? Pugmill 3. How is the AC measured with a drum plant? By metering (continuous delivery usually set as a gallon/minute based on aggregate tons/hour) 4. Where is the AC added in a drum plant? Direct injection into the drum

153 Construction and Materials Manual Chapter 8 Section 65 Materials Testing, Sampling, Acceptance Asphaltic Binder Materials Wisconsin Department of Transportation Materials sampling and testing methods and documentation procedures prescribed in chapter 8 of the CMM are mobilized into the contract per standard spec and standard spec Asphalt material sampling and testing methods as prescribed in CMM 8.65 are mobilized into the contract per standard spec and standard spec (15) Sampling Clarifications of sampling instructions for asphaltic materials, also see section CMM Each PG provided to the project must be tested. The number of samples to be taken and the sampling method used must be in accordance with the current version of the Combined State Binder Group Certification Method of Acceptance for Asphalt Binders. ftp://ftp.dot.wi.gov/dtsd/bts/quality/general Sampling Asphaltic Materials The method for sampling asphalt PG binders must be in accordance with the current version of the Combined State Binder Group Certification Method of Acceptance for Asphalt Binders. For all other types of asphaltic materials, the sampling method must be as specified in the standard specifications. Regional personnel will be responsible for observing the sampling procedure, filling out and attaching sample tags, and shipping of the samples procured at the job site. They should also make sure the following points are given appropriate attention: 1. Samples should be submitted in the proper type of container, see CMM All containers must be new and clean. 2. Solvent or solvent-saturated cloth should not be used to clean the inside of the containers. The insertion of a solvent-saturated glove into the container during handling is an undesirable practice that could contaminate the sample. 3. The sample should always be taken in the containers to be sent to the laboratory. Do not transfer the sample from one container to another. 4. When sampling through a spigot, drain off and waste enough material before filling the sample container, to ensure removal of all material in the sampling line. 5. The sample containers should be relatively full. A good guide would be to fill the container to within one-inch of the top. In a few instances, insufficient material has been submitted for the required testing. After the container has been properly closed, do not use any cleaning solvent in the area of the closure. 6. After the asphaltic material has been properly sampled and labeled, ship to the laboratory the same day, if feasible. Shipments that take an excessive amount of time to arrive at the laboratory and those inappropriately sampled may cause test results that deviate from the contract requirements Certification Method of Acceptance for Asphalt Binders Acceptance of asphalt cement by the Certification Method provides for acceptance of these materials for use on WisDOT projects upon the producer's or supplier's certification that the product as furnished to the contractor (or purchasing agency) complies with the pertinent specification and/or contract requirements. A list of certified suppliers can be found on the department s approved product list at: The current version of the Combined State Binder Group Certification Method of Acceptance for Asphalt Binders can also be found at this site. For samples tested by the department with non-complying results, the engineer should ensure that the procedure listed in the Certification Method has been followed (ex: AASHTO T-164). May 2015 Page 1

154 Construction and Materials Manual Chapter 8 Section 66 Materials Testing, Sampling, Acceptance Asphalt Mixture Design Wisconsin Department of Transportation Materials sampling and testing methods and documentation procedures prescribed in chapter 8 of thecmm are mobilized into the contract per standard spec and standard spec Asphalt material sampling and testing methods as prescribed in CMM 8.66 are mobilized into the contract per standard spec and standard spec ASPHALTIC MIXTURE DESIGN Provide an Asphaltic Mixture Design JMF (Job Mix Formula) report representing the materials intended for use along with their proportions for producing the final product. These procedures infer laboratory mixed and compacted specimens unless designated otherwise. Accountability for JMF Mix Design Reports is to be with HTCP certified personnel and comply with the materials and mix design requirements of standard spec LABORATORY STANDARD METHOD OF ASPHALTIC MIX DESIGN Description This method is used to determine the optimum asphalt binder content for virgin asphaltic mixtures and asphaltic mixtures containing recycled asphaltic materials (RAM). This method also defines the submittal requirements pertaining to mix design reports and materials, as well as any field changes affecting mix design reports General Required test procedures for aggregate and hot mix asphalt (HMA) are shown below in Tables 1 and 2. Table 1 Required Aggregate Test Procedures AGGREGATE TEST TEST PROCEDURE Materials Finer than No. 200 (0.75mm) AASHTO T 11 Sieve Analysis of Aggregates AASHTO T 27 Mechanical Analysis of Extracted Aggregate AASHTO T 30 Sieve Analysis of Mineral Filler AASHTO T 37 Liquid Limit of Soils AASHTO T 89 Plastic Limit of Soils AASHTO T 90 Los Angeles Abrasion of Coarse Aggregate AASHTO T 96 Specific Gravity and Absorption of Fine Aggregate AASHTO T 84 Specific Gravity and Absorption of Coarse Aggregate AASHTO T 85 Flat and Elongated Particles in Coarse Aggregates ASTM D 4791 Soundness of Aggregate AASHTO T 104 Freeze-Thaw AASHTO T 103 Fractured Faces (CAA) ASTM D 5821 Uncompacted Voids Content of Fine Aggregates (FAA) AASHTO T 304 Sand Equivalency (Plastic Fines) AASHTO T 176 Note: The majority of test result parameters are referenced in Table in standard spec or Table in standard spec July 2014 Page 1

155 CMM 8-66 Asphalt Table 2 Required HMA Test Procedures HMA TEST Practice for Superpave Volumetric Design for HMA Specification for Superpave Volumetric Mix Design Standard Practice for Mixture Conditioning HMA TEST PROCEDURE AASHTO R35 AASHTO M323 AASHTO R30 Standard Method for Preparing and Determining the Density of HMA AASHTO T 312 Specimens by Means of the SHRP Gyratory Compactor Bulk Specific Gravity of Compacted Bituminous Mixtures AASHTO 166 Using Saturated Surface-Dry Specimens Maximum Specific Gravity of Bituminous Paving Mixtures AASHTO 209 % Air Voids in Compacted Dense and Open Bituminous Paving Mixtures AASHTO 269 Resistance of Compacted Bituminous Mixture to Moisture ASTM 4867 Determination of Draindown for Uncompacted Asphalt Mixtures AASHTO T305 WisDOT Standard Specifications for Asphaltic Concrete Pavement standard spec Summary of the Practice 1. Select aggregate components and the asphalt binder to be used, and determine the required properties defining those materials. 2. Design an aggregate structure (or multiple trial aggregate structures). Determine aggregate component blend percentages. 3. Determine trial asphalt binder contents (estimated by experience or by calculation based on aggregate properties of trial blends). - Compact gyratory specimens using a minimum of 3 asphalt binder contents (0.5% increments) and covering a range to include the estimated optimum design binder content. Use Ndes for compaction effort. - Compare trial binder content results. Select an optimum design binder content (by either graphing or interpolating the trial data results) meeting requirements as stated in standard spec Evaluate additional properties at the selected optimum design binder content. - Moisture Susceptibility (using ASTM D 4867). - Validate compliance of %G mm at N max and N ini by compacting 2 specimens at the design binder content to Nmax gyrations. - For SMA designs the mixture draindown at optimum binder will be determined and listed. 5. Complete a mix design report identifying materials used and summarizing volumetric properties in meeting required specifications in CMM Submit the mix design report, and representative materials when requested or required, to the department for review per CMM Additional guidance for materials selection and component composition involved in the mix design process can be referenced in, but not limited to, the following: Superpave Mix Design Manual SP-2 (Asphalt Institute) Mix Design Methods for Asphalt Concrete MS-2 (Asphalt Institute) NCHRP 9-33 (A Mix Design Manual for Hot Mix Asphalt) NCHRP Report 673 (A Manual for Design of Hot Mix Asphalt with Commentary) Materials and Test Procedures: Additional Guidance Aggregates Refer also to CMM 8-60 and standard spec Test the aggregate source material for quality properties (LA wear, soundness, freeze-thaw, etc) in accordance with the current department policy and required frequency. Count the current construction season as one year of aggregate quality eligibility. The mix designer, using the previously listed test methods determines the aggregate properties with the following exceptions or comments: - Fine aggregate angularity (FAA) is determined using Method A (AASHTO T 304). July 2014 Page 2

156 CMM 8-66 Asphalt - Flat and elongated particles are determined using particles retained on the #4 sieve (4.75mm) and larger. The determination of the F&E percentage is based on weight; however, the sample size is intended to be by count (200 pieces, minimum) Asphaltic Binder Material Select an asphalt binder meeting the contract requirements and having been defined or graded according to AASHTO M320. (refer to CMM 8-65) The asphalt binder source and grade indicated on the JMF Mix Design report must represent the material used during the mix design process in determining the optimum asphalt content. If recycled asphaltic materials are part of the mix design additionally refer to standard spec If a binder PG is altered from the original design for field production purposes, a check (testing) to validate the following properties must be performed and reported/submitted prior to use: - TSR: for JMF report values less than or equal to 72.0%. - %G mm at N ini : for JMF report values greater than or equal to 88.5 (for E-10s and higher ESALs). - %G mm at N max : for JMF report values greater than or equal to If the resultant check indicates a need to adjust the mix design targets or component combinations to meet specifications, then additional testing and separate design submittal may be required by the engineer. Changes in the asphalt binder source during production are by notification to the engineer and to be documented showing approved new supplier Preparation of Mixtures Combine the aggregates and asphaltic binder noting the following exceptions: - The requirement for using trial aggregate blends as prescribed in AASHTO R35 is optional. - Compaction effort gyrations are set by WisDOT standard specs and may deviate from AASHTO R35. Additionally refer to standard spec Compaction of Specimens Produce the required compacted specimens (minimum of 2 specimens for each asphalt binder content) using AASHTO T 312 and AASHTO R30. For aggregate JMF blends with moisture absorption greater than or equal to 2.0% a 4-hour cure time is to be used and indicated on the JMF mix design report. Report the actual absorption value on the report and additionally state the cure time within the report or comment section Determination of the specific gravity of SGC compacted asphaltic (G mb ) Determine specimen Bulk Specific Gravity (G mb ), using AASHTO T 166, Method A. Report G mb value to three decimal places (0.001) Determination of the mixture maximum specific gravity (G mm ) Determine Maximum Specific Gravity, (G mm ), using AASHTO T 209. For aggregate JMF blends with moisture absorption greater than or equal to 2.0%, additionally use the supplemental procedure for mixtures containing porous aggregates not completely coated (dry back procedure). This data is to be listed on the JMF mix design report. A minimum of two tests must be run, one each at two different asphalt trial binder contents. Calculate the G se for each Gmm test run (to three decimal places, 0.001) and average the results. Use this calculated average Gse to determine all G mm values for the trial data. Report any G mm value to three decimal places (0.001) Report General The mix designer/laboratory creates a summary report to be submitted to the department for review, along with a copy to the department s regional office. This summary must include trial data used to determine the design optimum binder content Report Items The following is a breakdown of the minimal information needed to be listed on the mix design report. An example report can be found at the end of this section. Summary of Aggregate Source/Component and RAM Data: July 2014 Page 3

157 CMM 8-66 Asphalt - Source name, pit or quarry designation, legal description, for each component - Component Gradations: gradations for each aggregate and the final blend must be shown as the % passing (the nearest 0.1) for the1 ½ (37.5mm), 1 (25.0mm), ¾ (19.0mm), ½ (12.5mm), 3/8 (9.5mm), #4(4.75mm), #8(2.36mm), #16(1.18mm), #30(0.60mm), #50(0.30mm), #100(0.150mm), and #200(0.075mm) sieves. - The percent of each aggregate and/or RAM component as compared to the total aggregate. - LA Wear loss, % (include department test number or listed values). - Soundness loss, % (include department test number or listed values). - Freeze-thaw, % (include department test number or listed values, refer standard spec ). - Aggregate Bulk specific gravity (G sb ). Aggregate Blend Data: - For mixtures containing RAM extracted gradation data, G sb and percent extracted asphalt content is required. - Flat and elongated (Method B), %. - Coarse fracture/crush count, %. - Sand equivalency. - Fine aggregate angularity. - Moisture absorption %. - Bulk specific gravity (G sb ). - Effective specific gravity (G se ). Asphaltic Binder: - Binder source (supplier). - Binder performance grade. - Binder specific 77 / 77F (25 / 25C). - Mixing Temperature based on AASHTO M 320 or as recommended by the supplier for laboratory produced mixture evaluation. Mixture Properties (using trial asphalt binder contents): - Binder content, % (P b ). - Air Voids, % (V a ). - Maximum specific gravity (G mm ). - Bulk specific gravity of the compacted mixture (G mb ). - VMA (voids of the mineral aggregate), %. - VFB (voids filled with binder), %. Mixture Properties (design optimum asphalt binder content): - Binder content, % (P b );. - Maximum specific gravity (G mm ). - Bulk specific gravity (G mb ). - Air voids, % (V a ). - VMA (voids of the mineral aggregate), %. - VFB (voids filled with binder), %. - DP (dust/binder proportion), % (using effective binder content, P be, for calculation). - Gyratory compaction effort (for Nini, Ndes and Nmax). - %Gmm (for N ini, N des and N max ). - TSR (tensile strength ratio), %. - TSR Compaction Effort (N = x ). July 2014 Page 4

158 - Gmm Dryback Correction Factor, % (if applicable). For Recycled Asphaltic Pavement Mixtures also list: CMM 8-66 Asphalt - Added binder content, %. - Total binder content, %. - Extracted asphalt binder % (of recycled components) - Percent Binder Replacement (Pbr) Miscellaneous: - Name of W isdot - HTCP Certified HMATech (at level designated for mix design) identifying responsibility for mix design data. - Name of design laboratory facility, its address and phone number (contact location). - Design date (representing completion of the mix design work). - Design ID (unique number or name). - Mixture type reflecting approximate traffic load (ex: E-1). - Mixture nominal max size (ex: 1" or 25.0mm). - State project ID Report Submittal and Department Review General Mix design summary reports, and batches of blended aggregates if required or requested, are to be submitted to the department prior to paving and using one of the following two methods: Comparison Level or Express Level. Designation of a design laboratory, or a certified designer, to a specific submittal level is determined by the defined condition(s) or by department authorization. The department will also authorize movement between submittal levels. Submittals received after 4pm (Mon-Fri) will be acknowledged as arriving the following work day. The mix design report submittal and review activities are intended to occur during the paving season defined as April through November. Designs submitted in the off-season (December March) will be reviewed by April 1st or sooner on an as needed (or by request) basis. Department review schedules for these requests may vary Comparison Level Submittals This process requires submittal of the mix design summary report and blended aggregates representing the mix design Job Mix Formula (JMF). Materials are to be submitted to the department a minimum of 5 working days prior to paving and are to include g (15 lb) batches of the blended aggregate components (inclusive of any components containing Recycled Asphaltic Materials) and a minimum of three quart cans of design PG binder. The following conditions indicate a need to follow this submittal procedure: 1. Any design laboratory or certified asphalt mix designer submitting designs to the department for the first time (regardless of previous history for either). 2. Any design laboratory or certified asphalt mix designer having lacked submittals for a period of three consecutive construction seasons. 3. Any design laboratory or certified designer abusing the express submittal privilege (ex: multiple instances of incorrect or non-compliant data/information needing correction or formal amendment). Note: This condition will be identified and communicated when trending and then defined by notification from the department. The department will review the mix design summary report and acknowledge specification compliance by the 4th working day after submittal. Release from comparison level submittal requirements to express submittals will be by notification from the department Express Submittal Design laboratories or certified designers may use this submittal procedure with authorization from the department. The design laboratory must submit the mix design summary report (electronically) to the department for review and provide a copy to the department s regional office a minimum of 2 working days prior to start of paving. July 2014 Page 5

159 CMM 8-66 Asphalt 1.The department will review the mix design summary report and acknowledge specification compliance by the following work day after submittal. In the event that the submitted design does not meet specifications, or the individual contract requirements, the department will notify the mix designer and may elect to delay release of the review (potentially impacting paving); until such time that the specifications are met. HTCP Certified mix designers requesting mix design comparison testing should follow the requirements for Comparison Level submittals and alert the Bureau of Technical Services Truax Center Laboratory of the request to have properties checked. Use of this submittal procedure, while authorized for Express Level, does not negate further use of Express Level submittals Mixture Design Life A mix design review status carries over for subsequent construction seasons when all of the following are met: 1. Department specification changes have occurred, and the mix design still meets those specifications for any current contract. 2. Aggregate quality data is current per standard spec and sources are approved for use. The following link provides access to the list of the department approved aggregate sources 3. The mix design has been field tested during subsequent production a) Designs field tested during the previous construction season for non-state work are required to be tested in accordance with standard spec (4) by HTCP certified personnel and at department qualified laboratory facilities. Submit non-state production QC test data to regional project personnel. Note: For previous state work the information is already on file. b) For a non-production gap of a single construction season the design must be field tested in accordance with standard spec (4)during the current construction season, on non-state work by HTCP certified personnel and at department qualified laboratory facilities, prior to use on WisDOT projects Submit production test data to regional project personnel. c) If the design has field production gaps of more than a single construction season, a new mix design is required. 4. Design aggregate component blend percentages will not be changed by more than 20% in any combination at any single point during production. a) Note that any single component blend adjustment will result in a need to adjust additional components to balance the blend (ex: any component adjusted by 10% will also require an additional other 10% change between the remaining components, resulting in the maximum 20% referenced change). However, component blend changes are not accumulative so component blend changes back towards the original JMF will not be considered as exceeding the 20% maximum. The following example illustrates changes to proportions and how to assess blend changes: 1) For example if the original proportions for the aggregates are: Agg1 = 25%, Agg2 = 25%, Agg3 = 45%, Agg4 = 5%.Then the initial component blend first changes by adjusting Agg1 to 35% and Agg2 to 15% resulting in a 20% change from the JMF. Then a second change had Agg1 moved back towards the original JMF to 30% and changed Agg2 to 20% resulting in a 10% net change from the original JMF. The second change does not get added to the first change of 20%. Each change is independently assessed against the original JMF, not added to other changes. b) Blend changes indicating an excess of the maximum 20% away from the original JMF will not be considered the same mix design within the same season or any subsequent season. Continued use will require a new mix design or approval of the engineer (documenting the reason). 5. Any need for elimination or addition of new aggregate (inclusive of RAM) components will require a new mix design. 6. Recognizing design JMF target changes with associated QMP data from the end of the previous construction season will be at the option of the contractor but must be noted as such prior to initial paving Job Mix Formula (JMF) Changes During a construction season, JMF blend single aggregate component percentages are not allowed to go to zero (elimination). Elimination or addition of any new aggregate components requires a new mix design. No JMF change requests are to occur prior to completion of three individual production tests. Prior production test results need not be tied to state work. The contractor will notify the engineer of the proposed change in written form using a "Request for JMF Change" (Figure 1). Comments must include the sample test number that indicates when the change is to become July 2014 Page 6

160 CMM 8-66 Asphalt effective. Production changes or formal requests for JMF changes may not cause any target value to exceed mix design requirement limits of standard spec table or standard spec table 460-2, however production tolerances may allow for field mixture properties to exceed those targets. The requested change may become effective at a test point up to four individual tests before the test when the request was formally made. Documentation that the contractor and engineer had discussed a possible JMF Change must exist for the change to occur at a point prior to the test number on the formal request. Further changes, subsequent to the original property change, will not be granted until six additional individual test points (within the normal sampling frequency) for the affected mix (test) property have been generated. Each JMF sieve will be considered as an individual mix (test) property. Control chart(s) for the affected property(ies) will accompany the "Request for JMF Change" (Figure 1). An example JMF mix design worksheet is shown in Figure Amended JMF Reports and JMF Report Reviews Previously submitted mix designs needing to be edited or updated will be re-submitted along with an explanation for the nature of the change (and any supporting data). Examples of these instances could be: 1. Typographical Errors 2. Addition of PG binders in order to comply with CMM ( ) 3. Mix Design Signatures (HTCP Accountability) Non Traditional or Non-Standard Mixture Design Reports WMA: laboratory work completed at additive supplier recommended mixing and compaction temperatures. These temperature ranges are to be listed on the JMF report. For mix designs involving specialty products, components, or needing to meet a local special provision, identify in the comment section of the report or within the submittal correspondence. July 2014 Page 7

161 CMM 8-66 Asphalt Example Worksheets Figure 1 Request for JMF Change July 2014 Page 8

162 CMM 8-66 Asphalt Figure 2 JMF Mix Design July 2014 Page 9

163 APPENDIX 2: Mechanics of Mix Design & Recycling

164 Appendix 2: Mechanics of Mix Design & Recycling Page 2-1 Mechanics of Mix Design Mixture Characteristics: The materials presented in this section are related to dense-graded hot-mixed asphalt concrete. In a hot mix asphalt paving mixture, asphalt and aggregate are blended together in precise proportions. The proportions of these materials determine the physical properties of the mix and how the mix will perform as a finished product. In order for hot-mix asphalt concrete to function well, it must be designed, produced, and placed to give it certain required properties: - Stability - Durability - Impermeability - Workability - Flexibility - Fatigue Resistance - Skid Resistance Stability is the ability to resist distortions. Stability specifications should be high enough to handle traffic adequately. Factors influencing stability are: 1. Internal Friction o Shape o Texture o Gradation 2. Cohesion o Film Thickness o Viscosity Durability is the ability to resist changes in the asphalt, degradation of aggregate, and stripping of asphalt film. These factors result from weathering and/or traffic. Durability is improved by: 1. Using maximum asphalt content 2. Using densely-graded aggregate with stripping-resistance

165 Appendix 2: Mechanics of Mix Design & Recycling Page Compacting the mixture for minimum permeability Impermeability is the resistance of a mix to the passage of air and water into or through it. Virtually all asphalt mixtures used in highway construction are permeable to some degree. Workability is the case of placing and compaction. Workability is greatly affected by gradation. Mixtures which are too easily worked are referred to as tender mixes and are susceptible to distortion. Flexibility is the ability to adjust to gradual settlements and movement in the subgrade without cracking. Flexibility is influenced by: 1) asphalt content 2) gradation Fatigue Resistance is the ability to resist repeated wheel loading, causing tensile strains and stresses. Factors influencing fatigue resistance are: 1. Air Voids 2. Asphalt Viscosity 3. Layer Thickness 4. Asphalt Content Skid Resistance is the ability to minimize skidding of vehicle tires, particularly under wet conditions. The following factors have an important impact on skid resistance: 1. Surface Roughness 2. Aggregate Texture 3. Asphalt Content Many of the above characteristics are related. An improvement of one value can have a detrimental effect on one of the other values. The design process, therefore, presents a trade-off to balance the different parameters among the various characteristics. The design concept of mixture design was formulated by Bruce Marshall. The U.S. Army Corps of Engineers, through extensive research and correlation studies, improved and added certain features to the Marshall s original test procedure and developed mix design criteria. The Marshall method uses standard test specimens 2-1/2 inches high and 4 inches in diameter. A series of test specimens (3 per set), each containing the same aggregate blend but varying asphalt content, are prepared using specific procedures to heat, mix, and compact the asphalt-aggregate mixture. The two principle features of the method are 1) the stability-flow test, and 2) densityvoids analysis. Bulk specific gravity (BSG) determination is essential for the accurate density/air voids analysis.

166 Appendix 2: Mechanics of Mix Design & Recycling Page 2-3 The laboratory density becomes the standard by which the roadway density is measured. In Wisconsin, the DOT uses a percentage of maximum theoretical specific gravity (MSG) as measured by AASHTO T209, commonly known as Rice Specific Gravity. The durability of dense-graded asphalt concrete mixes is related to air voids. The allowable percentage of air voids in laboratory compacted specimens is between 3% and 5%. The voids in the mineral aggregate (VMA) are the air-void spaces that exist between the aggregate particles. The more VMA in the dry aggregate, the more space is available to accommodate the effective volume of asphalt (i.e., all of the asphalt except the portion lost by absorption into the aggregate) and the volume of air voids necessary in the mixture. Recycling Recycling provides an infinite source of material. Recycling in Wisconsin began by the late 1970s. Considerable maintenance costs have been saved because of recycling. Recycled material usually contains valuable aggregates and asphalt cement that can be reused. The milled and removed materials belong to the contractors who want to use this material in the most cost-effective way and that is in recycled HMA mixtures. However, the mixture containing RAP materials is required to meet the same specifications as a virgin mixture. In order to incorporate a RAP material in a mix design, the gradation of the RAP and the properties of the asphalt cement must be determined. Samples from the RAP stockpile are taken, and an extraction test is performed. The average of three extraction test results are usually used to characterize the RAP stockpile. The viscosity and penetration of the recovered asphalt are measured, also. Using the average aggregate gradation of the RAP stockpile, a blend with the available virgin aggregates is determined. The percent of RAP used is determined by the types of milled asphaltic pavement and the type of HMA facility so as to keep an efficient production while meeting opacity and emission requirements. Research by the author concluded that milled cold mixes will smoke more than milled hot mixes. The oxidation of asphalt is not uniform through the pavement. Depending on compaction and permeability, the upper portion of the pavement has oxidized more than the lower portion. The use of RAP requires modifications in the production facility. Typically, a sort is introduced in the middle of the drum through which the RAP material is introduced farther away from the flame. The percent RAP varies between percent, although in Wisconsin higher percentages are used. Viscosity blending charts are used to select a rejuvenating agent to mix with the RAP to restore the asphalt cement to its original viscosity. The grade of asphalt cement being added should be no more than two grades softer than the asphalt cement grade designed in the recycled mixture.

167 APPENDIX 3: QMP Award, Corrections, and Evaluation

168 APPENDIX: QMP Award Nomination Form The Quality Management Program Award recognizes outstanding certified highway materials technicians who have displayed exceptional leadership roles in developing quality materials used in highway construction projects. These winners are chosen from contractors, consultants, and the Wisconsin Department of Transportation. It is this industry support and joint partnering that makes this program a success. Some of the qualities attributed to the award winners include HTCP certification, HTCP promotion, development of cost savings, development of time savings, quality improvement, being a team player and possessing a positive attitude.

169 Quality Management Program Award Nomination Application This Outstanding Individual or Team is Nominated to Receive this Year s Quality Management Program Award Individual/Team: Address: City/State/Zip: Telephone: Employer: Work Address: City/State/Zip: Telephone: Fax : List individual or team nominated: Identify outstanding individual or team achievement(s) that exemplify this nomination for the Quality Management Program Award : *Application submitted by: Do you wish to remain anonymous? (* Required for nomination) Yes No Date: Please fax (608) or send completed application before November 1 of each year to Highway Technician Certification Program, University of Wisconsin-Platteville, 049 Ottensman Hall, 1 University Plaza, Platteville, WI

170 Quality Management Program Award Nomination Application This Outstanding Individual or Team is Nominated to Receive this Year s Quality Management Program Award Individual/Team: Address: City/State/Zip: Telephone: Employer: Work Address: City/State/Zip: Telephone: Fax : List individual or team nominated: Identify outstanding individual or team achievement(s) that exemplify this nomination for the Quality Management Program Award : *Application submitted by: Do you wish to remain anonymous? (* Required for nomination) Yes No Date: Please fax (608) or send completed application before November 1 of each year to Highway Technician Certification Program, University of Wisconsin-Platteville, 049 Ottensman Hall, 1 University Plaza, Platteville, WI

171 OOPS! Found an error? Course Title: Please describe the error and the page or topic where you found it: We might have questions. How can we reach you? Name: Date: Phone: Note to Development Team: Send updates to or call , or mail to HTCP, 1 University Plaza, University of Wisconsin-Platteville, Platteville, WI THANK YOU!

172 HIGHWAY TECHNICIAN CERTIFICATION PROGRAM (HTCP) EVALUATION The HTCP would appreciate your thoughtful completion of all items on this evaluation. Your comments and constructive suggestions will be carefully studied and will serve as a valuable resource to improve our course presentations: Course: Date: 1. Overall rating of this program: Outstanding Above Average Average Below Average Unacceptable Did the course meet your expectations? How well were you satisfied with the quality and quantity of the course materials? Comments about course materials/visual aids: 2. Instructor: Outstanding Above Average Average Below Average Unacceptable Effectiveness of course presentation: Responsiveness and interaction with students: Ability to communicate: Knowledge of course content: 3. Please fill in and rate overall effectiveness of laboratory instructor(s)/guest lecturer(s): Outstanding Above Average Average Below Average Unacceptable Comments: Please make additional comments about individual laboratory instructor(s)/guests lecturer(s) quality of instruction: