NYCDOT uses black mastic to repair distresses prior to ultrathin overlay

Asphalt Case Studies December 10, 2015
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Between December 13, 2014, and March 15, 2015, the New York City Department of Transportation (NYCDOT) filled nearly 160,000 potholes. But while all potholes need to be repaired, not all pothole repairs are the same.

 

The NYCDOT was considering reconstruction options for 1st Avenue, which had been reconstructed in 1983 using Portland cement concrete. Scott Roveto, director of technical services at the NYCDOT, was concerned about causing damage to old steam pipes, sewage pipes and electrical systems located below the roadway if full-depth reconstruction was done.

 

The section of 1st Avenue that needed to be repaired has nonstop traffic—an average of 26,957 vehicles per day. Adding to the causes of pavement distress is the extreme New York weather—temperatures range from 24°F to 82°F. The area also receives approximately 41.64 in. of precipitation per year, including freezing rain and snow in the winter months.

 

After evaluating the situation and all options, the NYCDOT decided to perform a thin lift asphalt overlay using a highly modified asphalt (HiMA) mix. It also wanted a product applied prior to the overlay that would reduce reflective cracking. Based on this decision, it contacted Crafco to discuss products the company offers.

 

NYCDOT officials met with Crafco personnel and the HiMA manufacturer. During the meeting, it was agreed that the mix would be adjusted to reduce reflective cracking. But the cracks, voids and potholes still needed to be treated to eliminate areas of low compaction when rolling the thin lift overlay.

 

The NYCDOT chose PolyPatch by Crafco to prepare the concrete pavement for the ultrathin overlay project. PolyPatch was chosen because of its ability to successfully seal the cracks and voids while providing a stress-absorbing interlayer directly over the distresses in the existing pavement. PolyPatch’s quick and simple application was also taken into consideration when making the decision, as was its ability to hold up to the location’s high volume of traffic prior to the overlay.

 

PolyPatch is designed for cracks too large for crack sealing and distressed surfaces that are too small for repaving. It is a versatile hot-applied, pourable, self-adhesive polymer modified asphalt binder containing selected aggregate to ensure good load bearing and skid-resistant characteristics.

 

The NYCDOT was pleased with the project results. PolyPatch effectively filled and leveled all voids while providing a waterproof structural repair within the project’s tight time restrictions.

 

Because of the successful use of PolyPatch on the 1st Avenue project, the NYCDOT has continued using PolyPatch on other projects, including pavement repairs on College Point Boulevard in Queens and Fordham Road in the Bronx. (These projects were conventional hot mix overlays, and not the ultrathin overlay.)

Overlay Init