Polymer-Modified Asphalts Enhancing HMA Performance. New Orleans, Louisiana January 28, 2003

Transcription

1 Polymer-Modified Asphalts Enhancing HMA Performance New Orleans, Louisiana January 28, 2003

2 Presentation Overview 1. Introduction 2. Phase I Overview 3. Summary of Interim Results & Findings

3 Study Objectives 1. Quantify the effect of using PMA as compared to conventional-unmodified HMA mixtures. 2. Identify conditions that maximize effect of PMA to increase HMA pavement & overlay life.

4 Phase I Tasks: 1. Update literature review. 2. Update contacts with selected agencies. 3. Review test sections with PMA mixes. 4. Select companion PMA & unmodified HMA test sections.

5 Phase II Tasks: 5. Predict performance of test sections. 6. Compare performance characteristics of PMA & unmodified HMA pavements. 7. Prepare study documents.

6 Reason for using PMA? R T F M D R T Response, % R = Rutting T = Thermal Cracking F = Fatigue Cracking M = Moisture Damage or stripping D = Durability R = Raveling T = Tenderness

7 Is There a Benefit Using PMA? Yes Unsure No Opinion Response, % Yes, BUT: Insufficient data to quantify that benefit.

8 Concern: Short-Term versus Long-Term Benefit? 120 Performance Measure PMA? Conv. Data needed to quantify long- Time, years term benefit.

9 Test Sections - Experiments LTPP: Core & Supplemental Sections! SPS-1; SPS-5; SPS-6; SPS-9! GPS-1; GPS-2; GPS-6; GPS-7 MTO Modifier Study Accelerated Pavement Tests, examples! FHWA ALF, Turner Fairbanks! NCAT Test Road! California HVS Studies Individual State Agency Test Sections

10 Selected Pavement Locations for Detailed Analyses in Phase II Not all LTPP sites located on map.

11 Experimental Factorial Pavement Cross Section Thin HMA Thick HMA Full-Depth HMA Overlays Foundation Fine-Grained Coarse-Grained Fine-Grained Coarse-Grained Fine-Grained Coarse-Grained HMA PCC Total No. PMA Sections Climate Freeze Non-Freeze Wet Dry Wet Dry

12 Phase I Comparisons: Load Related Cracking; area & longitudinal combined Rutting Thermal Cracking IRI, Smoothness Other Surface Distress

13 Types of Analyses; PMA Versus Unmodified Mixes Comparison of actual distress observations; companion sections Mechanistic-empirical analysis of performance history:!fracture, Load Related!Distortion, Load Related

14 Load Related Cracking Analysis Unmodified Mixes Versus PMA Mixes

15 Load Related Cracking: PMA Versus Unmodified Mixes Fatigue Cracking - PMA Mixes, % One data point Series1 represents a PMA & Companion Unmodified Section Line of Equality Fatigue Cracking - Conventional HMA Mixes, %

16 Fatigue Cracking Analysis PDMAP Fatigue Curve initially used in fatigue analysis. Log ( ) N f β = β 3.291β Log f 1 f 2 10 f 3 Log E HMA 3 10 ε t 6

17 Cracking versus Damage Index Each data point represents PMA Sectionsa PMA Section Area Fatigue Cracking, % DamageInde x = Conventional HMA Mixes n N actual f Damage Index

18 Rutting Analysis Unmodified Mixes Versus PMA Mixes

19 Rutting: PMA Versus Unmodified Mixes Rutting - Conventional Mixes, in One data point Series1 represents a PMA & Companion Unmodified Section Rutting - PMA Mixes,in. Line Of Equality

20 Rutting Evaluation Permanent-resilient strain ratio used in initial analysis. ε p Log = β ε r Log Log ( N ) ( T ) Logβ ( σ ) Log( η) ( V ) Log( V ) beff r β r3 a r 2 d Log

21 Findings Field & laboratory investigations of PMA mixes, overall summary: Enhanced Performance! 25 to 100 % increase in service life! 3 to 10 years increase in service life Reduced Maintenance Activities! Crew Safety! Traffic Delay

22 Finding Mechanistic-empirical analysis confirms need for different calibration factors for predicting performance of PMA mixes. PMA Sections Area Fatigue Cracking, % Damage Index

23 Observation Longitudinal cracking in wheel path is much lower in PMA mixes, as compared to conventionalunmodified mixes.

24 Finding and Conclusion " PMA mixtures do extend the service life of HMA pavements & overlays. The real issue is: QUANTIFICATION OF THE INCREASE IN SERVICE LIFE.

25 Performance Evaluations Fatigue Cracking; Area & longitudinal cracking Rutting Thermal Cracking IRI, Smoothness Other Surface Distress

26 Thank you for your attention - Any questions?