1. Performance & Distress of Flexible Pavement Serviceability/Performance Concept

2. Pavement Roughness Surface deviation that produces a response in the suspension system of a vehicle. It is the pavement property that is most noticeable to the traveling public. It is the primary quantitative measure of public satisfaction with the highway system Measured by a: Rolling straightedge (Benkelman Beam) Roughometer Profilometer

3. Pavement Roughness Benkelman Beam FWD

4. Pavement Roughness Roughometer Profilometer

5. Performance Is the area under the Serviceability Curve with Time. Performance of the Pavement decreases with time due to traffic and climate consumption Once the performance fall bellow a certain level the pavement is becoming impassable and unacceptable by the user.

6. Distresses in Flexible Pavement Distress is a condition of the pavement structure that reduces or lead to the reduction in serviceability. Distresses are expected as the pavement approaches its design life, However distresses are alarming if they occur early in the life of a pavement. Distresses in pavement can be identified at early stages and preventive measures should be taken before they result in failure. If preventive measures are not taken, then corrective measure must be performed.

7. Types of Distresses Cracking Distortion Disintegration Loss of Skid Resistance

8. Cracking Cracks occur from a variety of causes including: Stress from traffic axle loads Temperature changes in HMA layers Moisture or temperature changes in underlying layers

9. Types of Cracking It is important to identify exactly the type of cracking in the pavement structure so the cause of cracking is correctly assessed and the right preventive and corrective measures are taken.

10. Types of Cracking Fatigue or Alligator Cracking (closely spaced crack pattern) Causes: Excessive repetition of traffic loads Heavy traffic loads Inadequate drainage Poor subgrade

11. Types of Cracking Fatigue or Alligator Cracking (leads to potholes) Repairs: Removal and replacement Overlay over the entire surface

12. Types of Cracking Low Temperature Thermal Cracking (transverse cracking due to drop in temperature which causes shrinkage stresses that exceeds the tensile strength of HMA ) Causes: Drop in temperature Use of asphalts with high susceptibility to temperature Use of asphalt with high penetration

13. Types of Cracking Low Temperature Thermal Cracking (transverse cracking due to drop in temperature which causes shrinkage stresses that exceeds the tensile strength of HMA ) Repairs: Seal with liquid asphalt or any other suitable sealants Remove and replace

14. Types of Cracking Longitudinal Cracking (Individual cracks that run parallel to pavement centerline) Causes: Low temperature Asphalt with low tensile strength Oxidization High voids Heavy loads Earth movement

15. Types of Cracking Longitudinal Cracking (Individual cracks that run parallel to pavement centerline) Repairs: Sealing at early stage Removal and replacement at later stage

16. Types of Cracking Block Cracking (When HMA cracks transversely and longitudinally in approximately squared shape) Causes: High voids Oxidization Low strength HMA

17. Types of Cracking Block Cracking (When HMA cracks transversely and longitudinally in approximately squared shape) Repairs: Removal and replacement

18. Types of Cracking Reflection Cracking (propagation of underlying cracking through the surface ) Causes: Cracks in the old HMA underlayer

19. Types of Cracking Reflection Cracking (propagation of underlying cracking through the surface ) Repairs: Removal and replacement with milling of the old underlayer

20. Types of Cracking Slippage Cracking (Poor bond between the surface layer and the underlayer ) Causes: Poor bond

21. Types of Cracking Slippage Cracking (Poor bond between the surface layer and the underlayer ) Repairs: Removal an replace with stronger bonds between the layers

22. Distortion Permanent change in the shape of the pavement Types: Rutting Causes Load and high tire pressure Continuous densification Improper mix design (High AC content, Excessive fillers)

23. Distortion Permanent change in the shape of the pavement Types: Rutting Repairs overlay

24. Distortion Permanent change in the shape of the pavement Types: Shoving and Corrugation Causes Shear flow between layers Slippage between layers

25. Distortion Permanent change in the shape of the pavement Types: Shoving and Corrugation Repair Overlay

26. Disintegration Is the break up of the pavement structure (loss of individual pieces or the separation of individual pieces)

27. Disintegration Types Raveling: the lose of bond between the aggregates and asphalt and therefore between aggregates. The disintegration starts from the surface of HMA layer and moves downward. Causes: Aggregates cover with dust Segregation Low in-place density

28. Disintegration Types Raveling: the lose of bond between the aggregates and asphalt and therefore between aggregates. The disintegration starts from the surface of HMA layer and moves downward. Repairs: Removal and replacement

29. Disintegration Types Pothole: As a result of cracking and disintegration. Causes: Cracking Disintegration

30. Disintegration Types Pothole: As a result of cracking and disintegration. Repairs: Patching at early stage Overlay

31. Disintegration Types Polishing: As a result of traffic over use, aggregates susceptible to Abrasion. Repairs: Seal coat with good aggregates Milling and Overlay

32. Stripping Due to Excessive Moisture and an covered aggregates with asphalt

33. Bleeding Excessive Asphalt and Low void (Excessive compaction)