Asphalt Highway Stabilization

Applied Polymerics solves a long-standing problem of a sinking asphalt highway. Soil stabilization with polyurethane provides a solution and keeps the interstate highway open during repairs.

A section of I-40 in the Winston-Salem area had settlement issues. A stretch of the asphalt highway leading up to a bridge approach slab kept settling, causing a dip. The DOT had to repave, only to have it sink again. The likely cause was old organic fill underneath the highway decomposing over the years leaving voids and loose soil.

The DOT decided to solve the problem once and for all and then complete a full repaving project. Officials wanted to be sure they wouldn’t have to keep repaving that one section repeatedly.

Solution: Applied Polymerics was chosen to stabilize the soil beneath the stretch of highway using polyurethane resin so that it would stop settling. Highway reconstruction was not really an option since that would close the busy interstate highway for days or weeks. Our crew drilled an offset grid pattern and injected the soils underneath with a single-component, hydrophobic polyurethane from Prime Resins.

“We did permeation grouting below the asphalt roadway,” said project lead Scott Kammerer. “We chose that product as the best option because no lifting was required, just stabilization. After injection, the DOT would not have to worry about further settlement.”

The super low viscosity resin allowed for deep penetration of the voids and loose soil under the road. The resin reacts with moisture present in the soil and cures quickly to form a hard, water-insensitive mass. The consolidated soil properly supports the structure above.

Outcome: “Everything went well,” said Kammerer. “This was a pretty standard soil stabilization job. The project ultimately required approximately 900 gallons of material.  The section of highway remains stable, without settlement, years later.“