Asphalt Mixture Performance Tester

Transcription

1 Asphalt Mixture Performance Tester Ramon Bonaquist, P.E. Chief Operating Officer

2 Topics Development Implementation Status Uses AMPT Resources

3 What is the AMPT? Machine specifically for asphalt concrete testing Measures engineering properties of asphalt concrete: o Dynamic Modulus o Flow Number o Flow Time

4 Why Do We Need It? Volumetric design alone is not always sufficient o High traffic o Critical projects o Evaluate new materials Engineering properties needed for structural analysis o DARWin ME

5 Asphalt Concrete Mixture Design Performance Testing Evolution

6 Asphalt Concrete Mixture Design Performance Testing Evolution Pre-SHRP Marshall and Hveem design procedures included unreliable performance tests

7 Asphalt Concrete Mixture Design Performance Testing Evolution Pre-SHRP Superpave Level I Marshall and Hveem design procedures included unreliable performance tests Level II Level III

8 Asphalt Concrete Mixture Design Performance Testing Evolution Pre-SHRP Superpave Level I Marshall and Hveem design procedures included unreliable performance tests Level II Level III

9 Asphalt Concrete Mixture Design Performance Testing Evolution Pre-SHRP Superpave Level I Marshall and Hveem design procedures included unreliable performance tests Level II Level III

10 Asphalt Concrete Mixture Design Performance Testing Evolution Pre-SHRP Superpave Post SHRP NCHRP & FHWA Research Level I Marshall and Hveem design procedures included unreliable performance tests Level II Level III Wheel Tracking, Gyratory Compactor, Modulus, Creep, Repeated Load

11 Dynamic Modulus Test

12 Dynamic Modulus Test Mixture Stiffness Rutting Fatigue Cracking Stress Strain Time E* = σ ε 0 0

13 Flow Number Test Rutting Strain Stress Time Time

14 Flow Number Test Rutting Strain Stress Haversine Axial Compression Strain Curve Time Time Flow Number

15 Flow Time Test Rutting Strain Stress Time Time

16 Flow Time Test Rutting Constant Axial Compression Strain Stress Strain Curve Time Time Flow Time

17 AMPT is Not Prototype Equipment! Need Research Draft Test Method Prototype Equipment Verification Commercial Equipment Specification First Article Equipment Ruggedness Critical Aspects Improve Test Method Equipment Production Equipment Provisional AASHTO Test Methods Round Robin Testing Precision and Bias Training Engineering Practice

18 AASHTO Standards PP60, Preparation of Cylindrical Performance Test Specimens Using the Superpave Gyratory Compactor TP79, Determining the Dynamic Modulus and Flow Number for Hot Mix Asphalt (HMA) Using the Asphalt Mixture Performance Tester (AMPT) PP61, Developing Dynamic Modulus Master Curves for Hot-Mix Asphalt Concrete Using the Asphalt Mixture Performance Tester (AMPT)

19 Pooled Fund Study TPF-5(178) Implementation of the Asphalt Mixture Performance Tester (AMPT) for Superpave Validation Purchase AMPT s for Participating Agencies Develop and Deliver Training Course on AMPT NHI Training Course Asphalt Mixture Performance Tester Coordinate Testing

20 Pooled Fund Participation TX

21 How Has AMPT Data Been Used? Mixture Design o Flow Number o Dynamic Modulus Pavement Structural Design o Dynamic Modulus Materials Evaluation o High RAP Mixtures o RAS Mixtures o WMA o Additives and Modifiers

22 Flow Number in Mixture Design NCHRP Project 9-33, Mix Design Manual for HMA -Criteria for Minimum Flow Number Traffic Level Minimum Flow Million ESAL s <3 Number Cycles to < to < >30 740

23 E* in Mixture Design Quality Related Specifications (QRS) Software o Arizona State University o NCHRP-19 and 9-22 o Interpolates Database of DARWin ME Solutions Uses Dynamic Modulus Master Curve Predicted Rut Depth

24 Pavement Structural Design DARWin ME o HMA Characterized by a Dynamic Modulus Master Curve Plant Aged Conditions o Modulus Needed Stress-Strain Analysis Rutting Model Fatigue Cracking Model

25 Colorado Local Calibration

26 RAP/RAS Mixing Analysis Recycled Mixture Homogentiy is Important Dynamic Modulus is Very Sensitive to Binder Stiffness Good Plant Mixing Mixture Stiffness Consistent With Blended Binder Stiffness

27 RAP/RAS Mixing Analysis Dynamic Modulus Master Curve for Plant Produced Mixture As-Produced Stiffness Recovered Binder Master Curve Estimate Mixture Master Curve Hirsch Model Mixture Modulus = f(binder modulus, VMA, and VFA) Fully-Blended Stiffness Compare

28 Good Mixing

29 Good Mixing

30 Poor Mixing

31 Poor Mixing

32 Transportation Pooled Fund Study TPF-5(178) Search for Keyword AMPT or Contact Jeff Withee

33 SEAUPG AMPT User Group

34 Questions/Discussion Ramon Bonaquist 108 Powers Court, Suite 100 Sterling, VA