1. Asphalt Technology Course
Performance Testing of HMA
Performance Testing of HMA 1

2. Asphalt Technology Course
Learning Objectives
After this class, you will be able to …
Describe goals of performance testing
Describe factors considered for selecting tests
Describe most critical test parameters
Determine stress state in asphalt layer
Describe three major distresses
Conduct performance tests
Analyze test results
Performance Testing of HMA
Performance Testing of HMA

3. General Information
Performance Testing of HMA

4. Goals of Performance Testing
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Goals of Performance Testing
Identify mixtures prone to performance problems during the mix design process
Identify potential performance problems during production (QC/QA)
Predict performance during mix design
Warranties
Performance specifications
Evaluate new materials or design tools to improve performance
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 4

5. Why Distinguish Between Identify and Predict?
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Why Distinguish Between Identify and Predict?
Identify refers to a “go” or “no go” situation, e.g. “We think the mix will rut” or “We do not think the mix will rut”
Predict refers to providing an idea of the magnitude of the distress, e.g. “We think the mix will rut 13 mm after 10 million ESALs”
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 5

6. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Factors to Consider
Reliability (identification, prediction)
Time (sample preparation, testing)
Variability of results
Costs (equipment, operation)
Others
Calibration requirements
Sophistication of data reduction
Mobility of the equipment
Applicability to test cores
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 6

7. Most Critical Test Parameters
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Most Critical Test Parameters
Temperature
Frequency (loading time)
Load magnitude
Mode of loading
Specimen conditioning
Specimen type (lab vs. field)
Mixture variables: air voids
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 7

8. Question List three critical test parameters
Performance Testing of HMA

9. Major Distresses of Asphalt Pavements
Performance Testing of HMA

10. Flexible Pavement Deflection
Performance Testing of HMA

11. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Stresses
Compression
Tension
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 11

12. Vertical Compressive Stresses
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Vertical Compressive Stresses
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 12

13. Horizontal Tensile Stresses
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Horizontal Tensile Stresses
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 13

14. Pavement Shear Stresses
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Pavement Shear Stresses
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 14

15. Three Major Distresses
Rutting
Rutting in HMA (compaction, mix design)
Rutting in unbound base, subgrade (structure)
Fatigue cracking
Bottom-up cracking in thin pavements
Top-down cracking in thick pavements
Low temperature cracking
Shrinkage of HMA due to low temperatures
Performance Testing of HMA

16. Mix Rutting
Performance Testing of HMA

17. Fatigue Cracking Surface Base Surface Base Surface UnboundBase
Subgrade
Performance Testing of HMA

18. Bottom-Up Fatigue Cracking
Shear
Stress
at Crack Tip
Neutral
Axis
HMA
cracks
Bending Tension
Initiation
Propagation
Granular Base
Subbase
Fatigue cracking is significantly
related to the pavement structure
Performance Testing of HMA

19. Low Temperature Cracking
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Low Temperature Cracking
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 19

20. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Low Temperature Cracking
Low temperature cracks on surface
tensile
stress
tensile
stress
Low temperature
crack growth in HMA
Primarily affected by binder grade
Performance Testing of HMA
Performance Testing of HMA
HMA Performance Testing 20

21. Questions What are the three major distresses in asphalt pavements?
What may be the causes of these distresses?
Performance Testing of HMA

22. Tests for Rutting Resistance
Performance Testing of HMA

23. Tests for Rutting Resistance
Wheel tracking tests
Asphalt Pavement Analyzer (APA)
Hamburg Wheel Tracking Device (HWTD)
Static creep tests
Creep test
Flow time test
Repeated load tests
Flow number test
Performance Testing of HMA

24. Asphalt Pavement Analyzer
Performance Testing of HMA

25. APA Operating Characteristics
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
APA Operating Characteristics
100 to 120 psi hose pressure
100 to 120 lb load on the hose
Usually run for 8000 cycles
Temperature
Originally 50 °C (120 °F)
Currently recommend based on climatic PG grade
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 25

26. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Example of APA Results
HMA Performance Testing
Performance Testing of HMA 26

27. Example “Go/No Go” Criteria
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Example “Go/No Go” Criteria
Agency
Temp./Voids
Criteria, mm AL
67C, 4%
4.5 high traffic GA
64C, 7%
5 high traffic
6 medium traffic
7 low traffic VA
50C, 7%
3.5 high traffic
5.5 medium traffic
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 27

28. Which Mix Passes AL Criterion?
Performance Testing of HMA

29. Hamburg Wheel Tracking Device (HWTD)
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Hamburg Wheel Tracking Device (HWTD)
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 29

30. Hamburg Test Parameters
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Hamburg Test Parameters
Test combines rutting performance with moisture susceptibility
Load = 685 N (154 lb)
Full test is 20,000 passes
Temperature - 50 to 60 C
VTM %
Tested under water
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 30

31. Example of HWTD Results
Performance Testing of HMA

32. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
HWTD Criteria
CO:
10 20,000 passes
TX: (0.5 in failure rut)
10,000 passes for PG 64-XX
15,000 passes for PG 70-XX
20,000 passes for PG 76-XX
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 32

33. Which Mix Passes CO Criterion?
Performance Testing of HMA

34. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Creep Test
Results do not correlate well with pavement rutting
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 34

35. Flow Time (Ft)Test
D(t) = ε(t)/σd
Performance Testing of HMA

36. Flow Time Test (cont.)
- Primary: strain rate decreases with loading time
- Secondary: strain rate is constant with loading time
- Tertiary: strain rate increases with loading time
- Lower flow time should correspond to greater rutting in the field
Performance Testing of HMA
HMA Performance Testing 36

37. Flow Number (FN) Test 7% voids Deviator stress = 70 – 100 psi
Confining pressure = psi
Performance Testing of HMA

38. Flow Number Test (cont.)
- Primary: strain rate decreases with loading time
- Secondary: strain rate is constant with loading time
- Tertiary: strain rate increases with loading time
- Lower flow number should correspond to greater rutting
Performance Testing of HMA

39. Example of Proposed FN Criteria (based on Fn vs. rate of rutting)
Traffic, ESALs
Rut Threshold
9.5 mm
12.5 mm
1 million
105 89
3 million
202
171
5 million
274
232
7 million
335
284
10 million
414
351
Test temp: 58C, Confining pressure = 70 psi,
Deviator stress = 10 psi; Plant produced mixes

40. Tests for Fatigue Cracking Resistance
Performance Testing of HMA

41. Tests for Fatigue Cracking
Bottom-up fatigue cracking
Bending Beam Fatigue Test (BBFT)
Push-Pull Test
Top-down fatigue cracking
Energy Ratio (MR, IDT)
Performance Testing of HMA

42. BBFT
Performance Testing of HMA

43. Beam Preparation
Performance Testing of HMA

44. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Beam Fatigue Testing
Beam size – 2.5” by 2” by 15”
Usually 7% VTM
0.1 sec load and 0.4 sec unload
Fatigue tests are usually plotted as log strain vs Log N (number of cycles)
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 44

45. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Fatigue Testing
Controlled stress
Applicable for thick AC pavements
Controlled strain
For pavements less than 2 inches
50% loss in initial beam stiffness
Previous research indicates shift factors of 10 to 80 for number of cycles to failure in field versus lab (more cycles in field)
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 45

46. Example Fatigue Test Result
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Example Fatigue Test Result
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 46

47. Beam Fatigue Testing – Failure Propagation
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Beam Fatigue Testing – Failure Propagation
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 47

48. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Fatigue Curve
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 48

49. Which Mix Would Last Longer?
Performance Testing of HMA

50. Tests for Low Temperature Cracking Resistance
Performance Testing of HMA

51. Tests for Low Temperature Cracking
Temperature Stress Restrained Specimen Test (TSRST)
Indirect Tensile Test (IDT)
Semi-Circular Bending Test (SCB)
Disc-shaped Compact Tension Test (DCT)
Texas Overlay Tester (OT)
Performance Testing of HMA

52. Temperature Stress Restrained Specimen Test (TSRST)
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Temperature Stress Restrained Specimen Test (TSRST)
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 52

53. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
TTI Overlay Tester
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 53

54. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
TTI Overlay Tester
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 54

55. Tests for Mechanistic Properties for Pavement Design
Performance Testing of HMA

56. M-E Pavement Design Climate Materials Traffic Structure Response
Level 1: I know a lot about this input…
Level 2: I know some about this input…
Level 3: I know very little about this input…
Traffic
Materials
Structure
Time
Damage
Damage Accumulation
Distress
Response

57. Dynamic Modulus (|E*|)
Performance Testing of HMA

58. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Specimen for E* Test
150 mm by 100 mm,
cored from SGC specimen
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 58

59. E* Test Parameters Specimen Va = 7±0.5% AASHTO TP 62 – Full procedure
Test temperatures: -10, 4.4, 21.1, 37.8, 54.4oC
Frequency: 25, 10, 5, 1, 0.5, 0.1 Hz
AASHTO TP 79 – Reduced procedure
Test temperatures: 4.4, 21.1, ( )oC
Frequency: 10, 1, 0.1, (0.01) Hz
Use Hirsch model to predict max E*
Performance Testing of HMA

60. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
E* Test Results
osin(t)
/ o o o
,
osin(t-)
Time, t
Performance Testing of HMA
Performance Testing of HMA
HMA Performance Testing 60

61. Master Curve Development
Asphalt Technology Course
Master Curve Development
70F
Performance Testing of HMA
Performance Testing of HMA 61

62. Asphalt Technology Course
Shift Factor 58 86
Shift factors vary with HMA mixtures
Performance Testing of HMA
Performance Testing of HMA 62

63. Time-Temperature Superposition
Asphalt Technology Course
Time-Temperature Superposition
70F
58F
86F
Performance Testing of HMA
Performance Testing of HMA 63

64. Question What is the input for asphalt material in ME design?
What is the curve used to present E*?
Performance Testing of HMA

65. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Summary
Rutting Tests
No test has demonstrated ability to identify/predict rutting over wide range of mixes and climates
Several agencies have developed local criteria to identify rut susceptible mixes with torture testers
Repeated load test appears promising
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 65

66. Asphalt Technology Course
Asphalt Technology/Chinese Delegation
Asphalt Technology Course
Summary
Fatigue Tests
Good for ranking mixes
Difficult to relate to field
Low Temperature Cracking Tests
Several tests are being evaluated
Binder testing may be used for most applications
Test for ME pavement design
Dynamic modulus
Performance Testing of HMA
HMA Performance Testing
Performance Testing of HMA 66