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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Background

Current 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 practices

such 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.

Cost

12 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