Longitudinal Cracking in Jointed Plain Concrete Pavement: Synthesis of Experiences in the Midwest
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Transcript of Longitudinal Cracking in Jointed Plain Concrete Pavement: Synthesis of Experiences in the Midwest
Longitudinal Cracking in Jointed Plain Concrete Pavement:
Synthesis of Experiences in the Midwest
Robert Schmitt and
Sam Owusu-Ababio,
Univ of Wis - Platteville
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Outline Background
Objectives
On-line Survey
Survey Results
Summary
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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
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BackgroundCurrent problems with widened PCC: Observing Longitudinal Cracking Lacking information as to why
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Objectives Understand causes of longitudinal
cracking Survey six states in Midwest Input for developing guidelines
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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
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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 practicessuch as thickness, tie bars, etc.
On-line Survey
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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
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Cross-Section
What are selection criteria & most common panel widths?
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Criteria for Cross-Section
Other: 3/4 had no concrete pavements under their jurisdictions; 1/4 use state roads "standards"
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Panel Widths 2-Lane, 2-Way Rural
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Panel Widths 2-Lane, 2-Way Rural
Other: state standard
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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.
Cost12 ft 10 6 5 4 10 5 13 ft 1 0 1 0 0 114 ft 0 0 0 0 0 015 ft 1 1 4 2 5 4
Other 3 2 2 1 4 4
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Panel Widths 4-Lane, 2-Way Rural
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Panel Widths 4-Lane, 2-Way Rural
Other: mostly indicated no multi-lane JPCP under their respective jurisdictions.
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Panel Width Traffic
volume
Percent truck traffic
Ease of constr.
Hwy Func.Class
Pavt. Thick.
Constr. & Maint.
Cost12 feet 7 5 5 2 8 4
13 feet 1 0 2 0 0 2
14 feet 1 0 2 0 1 2
15 feet 0 0 1 1 1 2
Other, please specify
3 3 2 3 5 2
Criteria by Panel Width, 4-Lane
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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
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Longitudinal Cracking … why?
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Longitudinal Cracking occurrence
Other: Subgrade issue rather than width; No significant difference between panel widths
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Longitudinal Cracking by Thickness
Other: Majority specified 6-in thickness having the highest frequency of longitudinal cracking
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Longitudinal Cracking by Trans. Jt.
Other: 20-ft transverse joint spacing; not sure
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Longitudinal Cracking by Tie Bars
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Longitudinal Cracking by Constr. Bars
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2-Lane Constr. and Width
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Multi-Lane Constr. and Width
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Longitudinal Cracking by Location
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Topography
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Longitudinal Cracking by Topo.
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Topography and Width
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Premature Long. Crack.1 month to 5 years
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Rout and seal Cross-stitching Partial or full panel replacement
Methods for Fixing Long. Crack.
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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
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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
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SummaryFactor 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.
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More Information
wisdotresearch.wi.gov
Longitudinal Cracking on Widened Pavements
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Thank You
Survey Respondents