Allegheny County / Pittsburgh International Airport

"The American Concrete Paving Association suggested an epoxy injection repair that had been used successfully in Denver to repair shrinkage cracks in a new airport runway surface. With the contractor’s help, we identified and tested two possible epoxies. Both manufacturers’ representatives demonstrated their products by repairing a dozen cracks each. Post-injection testing was performed by analyzing cores from the test sites.

Based on visual examination of the penetration depth of the material, the polymer product, Roadware 10-Minute Concrete Mender (tm) from Elas-Tech (Roadware Applicator) was selected for further testing. It had penetrated to the bottom of the crack easily with its low coefficient of viscosity. It was also applied easily with an application gun and did not require preparatory steps for the crack. The polymer stained the concrete surface amber, however, so we used cement powder to absorb excess material and minimize staining.

Core samples of the concrete that was uncracked and the concrete that was cracked and sealed with the polymer material were tested for freeze-thaw and scaling resistance. The tests concluded that the concrete core that had been cracked and then sealed with the polymer material exceeded the performance of the uncracked concrete sample.

Repairs Appear to Be Successful

As soon as the client approved the repair method, the contractor applied the material to the cracks in accordance with the manufacturer’s instructions and then sprinkled cement powder on top of the uncured polymer to absorb excess material. There was very little evidence of the cracks after cleaning.

A ten-year extended warranty provided by the contractor as a negotiated settlement of this slab cracking calls for annual pavement inspections and for the contractor to make additional repairs as needed. The pavement inspection team has concluded that the pavement remains in an excellent range, with no change in its condition each year since opening to traffic in October of 1997. No additional repairs have been required, and even the surface stains of the concrete are not visible anymore."

The above text is from the published article below. Please click on the link to read the full article.

Lessons Learned on a Runway Reconstruction Project
By Peter Florian, Herndon, Virginia 1-703-742-5748