1. The Mechanisms of Healing of Asphalt Pavement By DingXin Cheng For Dr. Lytton’s Micromechanics Class November 11, 2002

2. 2 Outline Surface Free Energy Concept Fatigue and Healing Analysis Mechanical Testing Results Healing Mechanisms

3. 3 Surface Free Energy

4. Measurement of Asphalt -Wilhelmy Plate

5. Measurement of Aggregate – Universal Sorption Device (USD)

6. 6 lab field shift factor K 2f K 2I Log N f Log  CALCULATED STRAIN Fatigue shift factor

7. 7 Fatigue and Healing Model -(1) Fatigue model without rest period Where,

8. 8 Fatigue and Healing Model -(2) Fatigue model considering the healing effect

9. 9 Healing Curve

10. 10 Short-Term Healing Rate vs. Non-Polar Component

11. 11 Long-Term Healing Rate vs Polar Component

12. 12 Summary of Effect of Surface Free Energy on Fracture Fatigue Healing Healing potential is promoted with Reduced  LW Increased  AB

13.  LW and Healing Potential

14.  AB and Healing Potential

15. 15 Testing Results and Healing Analysis - Aging Effect

16. 16 Asphalt Binder Fatigue Testing including Healing Effects

17. 17 DMA Fatigue Data for AAM-1 NfNf

18. 18 DMA Data Fatigue for AAD-1 NfNf

19. 19 Asphalt Mixture Healing Testing -by Si, et al.

20. 20 Result Comparison Table Healing Potential Level AAD-1AAM-1HCR Surface Energy LowMedianHigh Binder Fatigue Test LowMedianHigh Mixture Fatigue Test LowMedianHigh

21. 21 Mechanisms of Healing

22. 22 Acid-Base Components of Surface Energy - Acid-Base Intermolecular Force

23. 23 Acid-Base Attracting Energy Potential Two Particles

24. 24 Attracting Energy Potential of One Mole Material

25. 25 Repulsion Due to Electron Orbital Overlap

26. 26 Net Acid-Base Attraction Energy

27. 27 Potential Energy of Acid-Base Interaction Versus Inter-particle Distances

28. 28 Lifshitz-van der Waals Components London Dispersion Force Debye Induction Force Keesom Orientation Force

29. 29 Net Lifshitz-van der Waals Potential Energy

30. 30 Potential Energy of Lifshitz-van der Waals Interaction Versus Inter-particle Distances

31. 31 Comparison of AB and LW Potential Energy Changing with Inter-particle Distances

32. 32 Healing Mechanism Microcracking Van der WaalsAcid-Base Forces

33. 33