1. PAVEMENT MAINTENANCE 1 Part 3: Potholes and Cracks Idaho Roads Scholar Program

2. Objectives n Explore alternatives for repairing potholes, n Review options for extensive patching, n Investigate methods and materials for treating pavement cracking.

3. HOW A POTHOLE DEVELOPS

5. Elements of Successful Pothole Patching n Use high-quality patching materials, which are cost- effective compared to less expensive products. n Place--do not throw-- material in the patch area. n Compact every patch.

6. High Quality Cold Mixes Include: n Carefully selected aggregate types and gradations u Very clean, durable aggregates u Very little sand-mixtures are porous n Polymer modified binder n Additives that promote adhesion in wet conditions

7. Asphalt Cold Patch Materials n Standard Spec 00745.00 Asphalt Cold Patch-High Performance n Qualified Products List available describing suitable materials

8. “There’s a gentleman here to see you about potholes.”

9. Permanent Repairs

10. Dig Out and Repair n Identify area affected n Remove to sound material n Clean, tack edges n Place patching mixture n Compact n Check level

11. Mark Area to be Patched Mark patch area, extending at least 1 foot outside of distressed area.

12. Remove Failed Materials

15. Place Patching Mixture

16. Spread Mixture Carefully

17. Compact Each Lift Thoroughly

18. Straight-edge the Patch

19. Blown-in Pothole Filler

20. Blown-In Filler SPRAY INJECTION The hole is cleaned with a high volume blower. A tack coat of asphalt is applied to the area. A mixture of aggregate and hot asphalt fills the hole. A finish coat of aggregate, and traffic flows.

21. Patching Rules of Thumb n Dig out 1 foot beyond the visible cracking n Don’t rock the jackhammer n Dig out at least 1 1/2 times the thickness of the failed AC n Compaction, compaction, compaction.

22. Questions? Potholes and Cracks

23. Crack Treatments Purpose Used to prevent water and debris from entering individual cracks in the asphalt pavement surface n Crack treatments are both a corrective and preventative maintenance treatment.

24. Crack Sealing Distress Type Fatigue Cracking Linear & Block Cracking “Stable” Rutting Raveling Flushing/Bleeding Roughness Friction Loss Moisture Damage Shoving Extent of Problem Minor Major Feasible Not Appropriate Feasibility

25. Crack Sealing Distress Type Fatigue Cracking Linear & Block Crack “Stable” Rutting Raveling Flushing/Bleeding Roughness Friction Loss Moisture Damage Shoving Extent of Problem Minor Major Effective Marginal No Impact Effectiveness

26. Crack Repair Guidelines n n Filling (sand or sand-emulsion slurry) n n Patching (cut and replace material) > 3 /4 inch (19 mm) n n Crack Fill (short life, prep for resurfacing) n n Crack Seal (> 5 yr life) 1/8 – 3/4 inch (3 – 19 mm) n n Do nothing n n Fog seal n n Surface treatment (chip seal, slurry, etc.) < 1/8 inch (3 mm), non- working Treatment OptionsCrack Width

27. Don’t do this!

28. Or this!

29. Proper Crack Sealing Technique

30. For Effective Crack Sealing: n Perform sealing during late fall/early spring when cracks are open. n Sealing does not proceed if rain is imminent. n Ambient or surface temperature should meet manufacturer’s requirements—usually 40F and rising for routing and sealing. n Use appropriate materials.

31. Preparation is Key! F Spray the weeds in advance F Clean the pavement surface. F Provide for traffic control. F Clean the crack, removing any moss or grass out of crack. F Dry the crack if necessary. (Hot air lance) F Fill it with crack seal material. F Apply something to surface of seal to minimize the tackiness.

32. Pavement Preparation n Cleaning and Drying u Broom u Compressed Air u Sandblasting u Hot Air Blasting (Heat Lance)

33. Cracks Must Be Clean & Dry Use Compressed Air Note: Be Sure Compressor Is Equipped With A Moisture Trap

34. ...Or Clean with a Hot Air Lance n Up to 3000°F n > 2000 ft/sec blast velocity n Propane burner-no flame n Conducted immediately ahead of sealant installation (5 mins or 50 yards max) Comments: n For wet conditions, lance can improve performance n Otherwise, compressed air may be more effective (Québec study)

35. Rout and Seal n Cut the pavement to a prescribed width and depth n Improves sealant performance u Better adhesion u Reduced tensile stress on material Crafco, Inc

36. W D W = 0.5” to 0.75” D = 0.5” to 0.75” Typical Dimensions: Crack Sealing

37. Traffic Control n Detour traffic until seal cures n Cover sealant with sand for quick opening n Begin filling at pavement centerline

38. Blotting Materials n Dry sand n Toilet paper (proven effective in SHRP research!)

39. Crack Seal Materials n Standard Spec 00746.00 Poured Filler/ Hot Poured n Qualified Products List available describing suitable materials

40. Crack Seal n The most common product used: D1190 n Cost per pound: $0.26 n Cost per linear foot to crack seal: $0.40 n Should reseal after 5 years?

41. Crack Sealing

42. Crack Sealing Rules of Thumb n For linear cracks only (not intended form alligator cracking) n Clean cracks with forced air or heat lance n Don’t over-fill crack with sealant; avoid surface smears n Sweep up excess sanding

43. Review n Investigate methods and materials for treating pavement cracking, n Explore alternatives for repairing potholes, n Review options for extensive patching.

44. Questions? Potholes and Cracks

45. Small Group Activity n Identify the distress n Describe the cause n Outline the optimum maintenance repair 10 Minutes

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49. AI 38: Use Group AI 38: Use for Group Photo No. 4:

50. AI 30: Use Group AI 30: Use for Group Photo No. 5:

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52. AI 47: Use Group AI 47: Use for Group Photo No. 7: