Guideline for the Implementation of the Mechanistic Empirical Pavement Design Guide (MEPDG) for the Concessionary NovaDutra

Transcription

1 Guideline for the Implementation of the Mechanistic Empirical Pavement Design Guide (MEPDG) for the Concessionary NovaDutra 7 th Brazilian Congress on Highways and Concessions (CBR&C) Maria Carolina Rodezno Kamil E. Kaloush October 26, 2011

2 Outline ASU CCR NovaDutra collaborative study MEPDG introduction and overview Required input data NovaDutra case studies Summary and Recommendations

3 ASU CCR NovaDutra Study Objective Started early 2011 Framework for assessing MEPDG for NovaDutra On-site staff collaboration Collection of input data Materials laboratory characterization Pavement sections for initial assessment

4 MEPDG The overall objective of the Guide for the Mechanistic-Empirical Design for New and Rehabilitated Pavement Structures is to provide the highway community with a stateof-the-practice tool for the design and rehabilitated pavement structures, based on mechanistic-empirical principles. Flexible pavement: ASU Rigid pavement: ARA

5 Pavement Design State of the Art AASHTO 93 State-of- Practice MEPDG State-of-the-Art Empirical Mechanistic- Empirical Mechanistic Statistical models from road tests -Calculation of stresses / strains -Empirical pavement performance models Mechanics-based pavement performance models

6 Benefits of M-E Design Approach Improve design reliability Improve rehabilitation design Includes method for local calibration Better evaluate impact of Traffic levels / seasonal / drainage effects / yearly changes in materials

7 MEPDG Highlights An Analysis Method An Iterative Design Method Predict performance over time. Relates pavement material characteristics with their performance in the field Calibrated based on LTPP data. Capability to adapt to local conditions New & rehabilitated pavement designs

8 Design Process EICM Climate Inputs Material Properties Traffic Transfer Functions Predicted Performance Empirical Analysis Mechanistic Analysis

9 MEPDG Hierarchical Design Inputs Level 1: Most reliable, data from laboratory testing Level 2: Intermediate level of reliability. Inputs estimated through correlations Level 3: Lowest level of reliability. Default values provided by the program

10 Input Level Selection The importance of the project Information available at the time of design Resources & time available to the designer to obtain the inputs

11 Predicted Distresses

12 Design Procedure Select an initial trial pavement structure Identify pavement cross section Specify layer material types & thickness Is Seasonal Analysis required? Two options EICM (Enhanced Integrated Climatic Model) Monthly Seasonal values

13 Main Inputs in the MEPDG Climate Traffic Material Input/Pavement Structure

14 Climate in the MEPDG Weather information HOURLY air temperature Precipitation wind speed percentage of sunshine ambient relative humidity Seasonal or constant water table depth

15 NovaDutra Climate Needs EICM in MEPDG only includes United States. Climatic files can be created, but should be in the same format used in EICM. National Institute of Meteorology (INMET) in Sao Paulo and Rio de Janeiro hourly data was not available in continuous basis ( a minimum of 2 years data is required) Hourly percentage of sunshine not available

16 Traffic Data in MEPDG Number of axles by: Axle type Truck type Axle load interval Number of axles within: Each year Season within a year Each hour

17 NovaDutra Traffic Needs There are 4 WIM stations along Dutra Presidente Highway an assessment of the data is required However, ESAL approach can be used in the MEPDG until accurate WIM data can be implemented

18 Materials Input Asphalt Concrete Layer a. Asphalt General mix volumetrics b. Asphalt Binder consistency tests / AC/PG grade ASTM Ai-VTSi G * ( 10 1 sin ) c. Mix Stiffness Dynamic Modulus E* Predictive Model OR

19 Log log-viscosity (cp) Binder PG Grading PG grading that best match the A i and VTS i values from standard binder tests I-17 Project AR I-17 Project AR PG I-17 Project PG I-17 Project PG ADOT Virgin PG Log-Temperature (Rankine) Binder Type A i VTS i PG AR PG PG AR PG

20 NovaDutra Materials Lab

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22 Materials Input Unbound Materials (Base, Sub-base, Subgrade) For Level 1 analysis, MEPDG requires resilient modulus data Equipment acquired by ND capable of conducting resilient modulus testing

23 NovaDutra MEPDG Assessment Initial Efforts Preliminary study : Dutra Presidente Highway between Sao Paulo -Rio de Janeiro To provide good understanding of needs for future calibration. The original highway built in 1960 s. (rehabilitation) Historical construction records? Seven pavement sections Traffic (moderate -high) Climatic zone (Sao Paulo- Rio de Janeiro) Pavement design life.

24 NovaDutra MEPDG Assessment Initial Efforts Two typical HMA layers selected Climatic data challenges: 2 climatic location from Louisiana; each with similar conditions to Sao Paulo and Rio de Janeiro Traffic level: ESAL was used. MEPDG design life for all scenarios was 8 years. Actual pavement condition data collection is in progress.

25 Preliminary Case Studies Section # Section ID Rehabilitation Records (year) North Bound SP 63-0 North Bound SP North Bound SP South Bound RJ South Bound SP North Bound RJ North Bound RJ Traffic Information (AADT) Heavy Traffic N (USACE) N (AASHTO) 1997, E E E E E E E E , E E E E , 2006, E E E E , E E E E , E E E E , E E E E+07

26 NovaDutra Pavement Sections HMA / Polymer modified Old HMA 4 12 cm 4 22 cm Granular Base cm Subbase 0 35 cm Subgrade Clay Silty Clay Silt Silty Sandy Clay

27 Mix Properties Property CA Binder G mm G mb G sb AC (%) V a (%) 3-5( as built=7) 4-6% (as built=7) V beff Binder Type CAP 40~ AC-40 CAP30-45~Pen Mix r 34 r 38 r 4 r 200 % % % % CA Mix Binder Mix

28 Total AC Rutting Results

29 Longitudinal Cracking Results

30 Reflective Cracking (%) Reflective Cracking Results NB SP 63-0 NB SP NB SP SB SP Pavement Section SB RJ NB RJ NB RJ

31 Summary Effort undertaken is a starting point for future implementations of the guide. Need to verify measures of distress. The calibration and validation of the models will be necessary for NovaDutra conditions. Full implementation will require a good amount of time and resources. Effective use requires materials and traffic databases beyond Level 3 and MEPDG defaults information. Complete climatic information is also needed in order to create required climatic files.

32 Total Rutting (in) Example 1: Fiber Reinforced Concrete Pavement Rutting Evaluation Thickness (in) Control 1 lb/ton

33 Fatigue (%) Example 2: Fatigue Cracking Evaluation Thickness (in) Control 1 b/ton

34 Example 3: HMA Rutting Generation-MEPDG Variable Levels Description AC thickness (in) 3 3, 6, 9 ESALs 3 2, 10 and 30x HMA rutting predictions (20 locations x 2 Air Voids x 4 gradations x 3 traffic levels x 3 thicknesses) HMA variable thickness Base Course-10" M R =40,000 psi Subgrade M R =20,000 psi

35 MEPDG AC Rutting (in) Rutting Criterion Approach 1.6 Rut k k k 1 *FN *ESALs * h 2 3 k4 1.4 AC Layer =3 in y = x R 2 = y = 5.442x R 2 = 0.69 y = 9.272x R 2 = Predicted Flow Number 2E+06 ESALs 10E+06 ESALs 30E+06 ESALs

36 Recommendations Continue Level 3 (best estimate, and default inputs); will provide useful information on the general rationality of MEPDG output / comparative analysis. Start Phase II: data collection activities necessary for calibration and validation of MEPDG. Detailed construction and traffic information. high priority efforts on testing to determine HMA dynamic modulus, binder testing and base materials moduli. Make use of quality deflection testing database (FWD) Collect distress and roughness information periodically. Establish test sections for future calibration and validation.

37 CCR-NovaDutra Implementation Projection Level 3 Level 2 Level ?

38 Concluding Remarks MEPDG is a major improvement for flexible pavement design Best approach for structural design Provides link between - Structural Design Asphalt Mixture Design

39 Acknowledgment Agência Nacional de Transportes Terrestres (ANTT) CCR NovaDutra