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

Outline Background Objectives On-line Survey Survey Results Summary

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

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

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

Guidelines Development Framework Panel Width Guidelines ACPA Professionals online discussion on JPCP Literature Review & Synthesis In-service Performance of Wisconsin JPCP Life Cycle Cost Analysis Survey of Midwest Pavement Professionals

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.

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

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

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

Panel Widths 2-Lane, 2-Way Rural

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

Criteria by Panel Width, 2-Lane Criterion Input for Panel Width Selection Traffic volume Percent truck traffic Ease of constr. Hwy Func. Class Pavt. Thick. Constr. & Maint. Cost 12 ft 10 6 5 4 13 ft 1 14 ft 15 ft 2 Other 3

Panel Widths 4-Lane, 2-Way Rural

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

Criteria by Panel Width, 4-Lane Traffic volume Percent truck traffic Ease of constr. Hwy Func. Class Pavt. Thick. Constr. & Maint. Cost 12 feet 7 5 2 8 4 13 feet 1 14 feet 15 feet Other, please specify 3

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

Longitudinal Cracking … why?

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

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

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

Longitudinal Cracking by Tie Bars

Longitudinal Cracking by Constr. Bars

2-Lane Constr. and Width

Multi-Lane Constr. and Width

Longitudinal Cracking by Location

Topography

Longitudinal Cracking by Topo.

Topography and Width

Premature Long. Crack. 1 month to 5 years

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

Cost to Repair Long. Crack. Low-end crack 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

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

Summary Factor Finding Panel Width 12 ft and 15 ft wide panels had higher longitudinal cracking frequencies than 13 ft and 14 ft wide panels. Pavement Thickness Thicker pavements (≥ 11 in) less cracking compared to thinner pavements. Trans. Joint Spacing More longitudinal cracking tends to occur with shorter joint spacing, 20 ft spacing. Tie Bars Split opinion whether there is an effect on longitudinal cracking. Construction-related Practices High frequencies with inadequate base compaction and poor joint saw-cut timing. Misaligned dowel bars and faulty vibrators also contributing factors. Panel Location More cracking at mid-panel compared to the vicinity of sawn longitudinal joints. Topography and Structures Cut/Fills, highway structures (bridges, drainage, culverts) and areas with differential subgrade heaving.

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

Thank You Survey Respondents