Deep Foundation Polyurethane Foam Injection
New asphalt road was showing signs of settlement due to uncompacted fill dirt below the compacted subgrade beneath the asphalt. Carolina Foundation Solutions injected polyurethane foam into the uncompacted fill and stiffen the soil to provide support to the asphalt roadway above. First 5/8” holes were drilled into the asphalt then pipe was drove down into the subgrade approximately 3 – 9 ft below grade. Carolina Foundation Solutions injected a pre-determined amount of AP440 foam into the fill dirt at the base depth and then lifted the pipe in 3 ft increments and injected additional foam. The asphalt roadway was monitored during the injection process with lasers for any lift of the asphalt roadway. Lastly, the pipe from the injection hole was removed and asphalt was patched by others. Carolina Foundation Solutions injected approximately 4,000 lbs of polyurethane foam. This proved to be a significant cost savings compared to the option of removing the existing asphalt and uncompacted material and replacing with new, compacted structural fill.