December 2016 Vol. 24, No. 4

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Pothole repairs with taconite last longer

Image of pothole repair being done

A microwave heating system makes effective patches possible in
winter.

University of Minnesota Duluth (UMD) researchers developed two improved options for pothole repair that are ideally suited to Minnesota’s cold and wet conditions. The techniques use taconite tailings—magnetite containing aggregate left over from the mining and processing of taconite for steel manufacturing. The research was part of a broader effort by MnDOT to evaluate current practices, materials, and policies for pavement patching and repair.

The first approach is a fast-setting, taconite-based compound, which was found to be especially well suited for rigid and relatively deep repairs in concrete pavements. The second approach uses a vehicle-based microwave heating system with taconite materials for in-place pothole and pavement repair; this technology proved very effective for repairing potholes in asphalt pavement at all temperatures, including very cold temperatures.

"Many taconite-based findings have lasted three years," says Lawrence Zanko, a senior research fellow at UMD’s Natural Resources Research Institute. “Our findings indicate that these two repair options have the potential to save maintenance departments thousands of dollars in labor costs annually, reduce traffic disruption caused by the frequent repair of repeatedly failing patches, and add efficiency and longevity to repairs.”

The final report includes two fact sheets on the new repair methods that maintenance agencies can use as part of their toolkit of options for repairing potholes and other pavement failures.

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