Presentation on theme: "Longitudinal Cracking in Jointed Plain Concrete Pavement: Synthesis of Experiences in the Midwest Robert Schmitt and Sam Owusu-Ababio, Univ of Wis - Platteville."— Presentation transcript:
Longitudinal Cracking in Jointed Plain Concrete Pavement: Synthesis of Experiences in the Midwest Robert Schmitt and Sam Owusu-Ababio, Univ of Wis - Platteville
3 Background Wisconsin DOT initiative in the early 1990s to construct widened concrete pavement, 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 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 Guidelines Development Framework
7 522 county engineers and pavement professionals from Iowa, Minnesota, Wisconsin, Illinois, Ohio, and Michigan Fall 2011 Questions centered on: (1) Criteria for determining panel widths on rural hwys (2) Commonly used panel widths (3) Frequency of longitudinal cracking occurrence (4) Probable causes of longitudinal cracking - Design features, construction practices such as thickness, tie bars, etc. On-line Survey
8 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 On-line Survey
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 Panel Width Criterion Input for Panel Width Selection Traffic volume Percent truck traffic Ease of constr. Hwy Func. Class Pavt. Thick. Constr. & Maint. Cost 12 ft ft ft ft Other322144
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.
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
28 Longitudinal Cracking by Topo.
29 Topography and Width
30 Premature Long. Crack. 1 month to 5 years
31 Rout and seal Cross-stitching Partial or full panel replacement Methods for Fixing Long. Crack.
32 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
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 FactorFinding Panel Width12 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 BarsSplit 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 LocationMore 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.
35 More Information wisdotresearch.wi.gov Longitudinal Cracking on Widened Pavements