Chapter 1

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This report documents results from 2 field sites, which include a total of 18 test sections:

• Maintenance area of the Minnesota Road Research Project (Mn/ROAD) test site, about 40 miles northwest of Minneapolis, MN (8 test sections non-trafficked).
• Route 2 in Erie and Lorain Counties near Vermilion, OH (10 test sections placed as full-depth patches in an old D-cracked pavement).

The sites were monitored for long-term performance to verify the effectiveness of freeze-thaw resistance technology. The performance monitoring included annual distress surveys and physical testing of cores taken from the concrete slabs at both sites. Wave velocity was measured at joints at the Ohio site to evaluate some treatments for D-cracking mitigation.

The field test sites were installed in 1992 in Minnesota and Ohio as a part of Strategic Highway Research Program (SHRP) Contract C-203, "Resistance of Concrete to Freezing and Thawing." The purpose of both installations was to validate the current frost resistance technology for new concrete in a field environment. In addition, at the Ohio site another evaluation was conducted to examine the effectiveness of methods to treat existing D-cracked concrete pavements to mitigate the effect of future D-cracking.

Briefly, results from the field and laboratory testing over a 6-year period after construction (1992 to 1998) showed very little visual distress at the surface or physical distress of portland cement concrete (PCC) cores taken from the interior portions of the test sections. Deterioration of some of the Ohio patches (especially in the wheel-path near transverse joints) was observed, but this is not believed to be due to a direct freeze-thaw mechanism. Some deterioration from D-cracking was observed at the joints of the original Ohio pavement. Further monitoring of the Minnesota site is recommended to obtain long-term distress and PCC deterioration information for use in validating the C-203 recommendations.

A description of the Minnesota field sites and monitoring results are provided first, followed by a description of the Ohio field sites and monitoring results. Conclusions reached and recommendations for further study are then presented.