INSIDE THE DOT
South Dakota Department of Transportation
Use of Polish-Resistant Aggregate in PCC
Dan Johnston, SDDOT
1/1/1900 - 1/1/1900
The premier course aggregate for PCC pavements in western South Dakota is Minnekahta limestone. Although the limestone is a superior aggregate in almost every respect, it suffers one serious drawback--a tendency to polish prematurely. Tining has improved friction and drainage on pavements with limestone aggregate, but current evidence suggests that polishing and reduced skid resistance remains a problem on high ADT routes such as Interstate 90 and certain urban sections. Methods are needed for design and/or construction of new PCC pavements with limestone aggregate.
1 Determine the extent of the polishing problem throughout the state.
2 Identify concrete pavement construction methods and/or mix designs which will enhance long term pavement skid resistance while maintaining the positive structural aspects of the existing Minnekahta limestone PCC pavements.
3 Evaluate field performance of practical methods and/or mix designs selected by the technical panel.
1 Conduct a literature review concerning skid number improvements of limestone PCC pavements including construction methods, mix designs, and other state DOT's experience.
2 Review current SDDOT data and identify age and extent of PCC pavement exhibiting polishing.
3 Identify factors responsible for loss of skid resistance.
4 Identify alternate construction methods and/or mix designs which will maintain a minimum skid number of 32 for a minimum of 20 years with an ADT of 10,000 to 12,000 while displaying positive structural performance similar to present limestone PCC pavements.
5 Determine incremental cost changes associated with each method and/or mix design.
6 Determine a method of evaluating each of the methods and/or mix designs in regard to predicted skid resistance loss, wear, fatigue, and distress (overall performance).
7 Provide an interim report summarizing research results to this point.
8 With technical panel approval, design and install test sections for evaluation.
9 Evaluate field performance of test sections.
10 Submit final report summarizing relevant literature, test results, research methodology, and conclusions.
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