Longitudinal Cracking in Jointed Plain Concrete Pavement: Synthesis of Experiences in the Midwest

1. Longitudinal Cracking in Jointed Plain Concrete Pavement: Synthesis of Experiences in the Midwest Robert Schmitt and Sam Owusu-Ababio, Univ of Wis - Platteville

2. Outline • Background • Objectives • On-line Survey • Survey Results • Summary

3. Background Wisconsin DOT initiative in the early 1990s to construct widened concrete pavement, 14-15 ft. • Limit pavement edge stress and deflection impacts • Reduce shoulder maintenance cost • Minimize exposure of maintenance crew to high volume roadways

4. Background Current problems with widened PCC: • Observing Longitudinal Cracking • Lacking information as to why

5. Objectives • Understand causes of longitudinal cracking • Survey six states in Midwest • Input for developing guidelines

6. Guidelines Development Framework

7. On-line Survey • 522 county engineers and pavement professionals from Iowa, Minnesota, Wisconsin, Illinois, Ohio, and Michigan • Fall 2011 • Questions centered on: • Criteria for determining panel widths on rural hwys • Commonly used panel widths • Frequency of longitudinal cracking occurrence • Probable causes of longitudinal cracking • - Design features, construction practices • such as thickness, tie bars, etc.

8. On-line Survey • 37 of 522 engineers responded with information • 4-month open period, Aug-Nov 2011 • Significant majority did not have PCC pavement in their county • Sample considered unbiased

9. Cross-Section • What are selection criteria & most common panel widths?

10. Criteria for Cross-Section • Other: 3/4 had no concrete pavements under their jurisdictions; 1/4 use state roads "standards"

11. Panel Widths 2-Lane, 2-Way Rural

12. Panel Widths 2-Lane, 2-Way Rural • Other: state standard

13. Criteria by Panel Width, 2-Lane

14. Panel Widths 4-Lane, 2-Way Rural

15. Panel Widths 4-Lane, 2-Way Rural • Other: mostly indicated no multi-lane JPCP under their respective jurisdictions.

16. Criteria by Panel Width, 4-Lane

17. So far….. • Panel width selection factors • Pavement thickness. Width-to-Thickness ratio. • Traffic volume • Percent trucks • Ease of construction • Construction and maintenance cost • Most commonly used panel widths • 12 ft and 15 ft for 2-lane 2-way rural pavements • 12 ft for multi-lane rural pavements

18. Longitudinal Cracking … why?

19. Longitudinal Cracking occurrence • Other:Subgrade issue rather than width; No significant difference between panel widths

20. Longitudinal Cracking by Thickness • Other: Majority specified 6-in thickness having the highest frequency of longitudinal cracking

21. Longitudinal Cracking by Trans. Jt. • Other: 20-ft transverse joint spacing; not sure

22. Longitudinal Cracking by Tie Bars

23. Longitudinal Cracking by Constr. Bars

24. 2-Lane Constr. and Width

25. Multi-Lane Constr. and Width

26. Longitudinal Cracking by Location

27. Topography

28. Longitudinal Cracking by Topo.

29. Topography and Width

30. Premature Long. Crack. • 1 month to 5 years

31. Methods for Fixing Long. Crack. • Rout and seal • Cross-stitching • Partial or full panel replacement

32. Cost to Repair Long. Crack. • Low-endcrack fill or rout-and-seal • $0.50/lf to $9/lf, avg $1.20/lf • High-end stitch or full-depth • $15/lf to $300/lf, avg $122/lf

33. Summary • 37 of 522 county engineers and pavement professionals from Iowa, Minnesota, Wisconsin, Illinois, Ohio, and Michigan • Aug-Nov 2011 • Significant majority did not have PCC pavement in their county • Sample considered unbiased

34. Summary

35. More Information wisdotresearch.wi.gov Longitudinal Cracking on Widened Pavements

36. Thank You Survey Respondents