Field assessment of a jointed concrete pavement foundation treated with injected polyurethane expandable foam

This paper describes in situ measurement results and analysis of a deteriorating jointed concrete pavement supported on open-graded aggregate subbase that was subsequently treated with high-density polyurethane foam. The foam was injected under pressure into the subbase to improve support conditions, mitigate faulting and improve load transfer efficiency (LTE) at the joints. A variety of in situ tests were conducted to evaluate ride quality, pavement deflections under dynamic loading, LTE at joints and cracks, pavement surface elevation changes, and drainage and stiffness of the treated subbase layer. Testing on the pavement surface indicated statistically significant improvements near cracks after treatment with reduced peak deflections and higher LTE, but the pavement ride quality measurements did not show improvement. Tests performed on the foundation layer indicated that the construction process resulted in concentrated zones of foam in the subbase with low permeability, low stiffness and high shear strength, compared with untreated areas.