Injected Polyeurethane Slab Jacking

Conventional methods for raising in-place concrete slabs to align roadway sections or to counteract subsidence requires pressure-injecting grout under the slab. As other transportation organizations have had success with the URETEK Method, which utilizes injected polyurethane, Oregon DOT elected to use this method to raise and stabilize a bridge end panel and adjacent concrete slab. A two-year research project was conducted to monitor the stability of the injected slabs and to evaluate the material. The slabs settled by up to 10.5 mm (0.413 in) after two years. The compressive strength of the polyurethane material was not reduced after underground exposure. The ability of the injected polyurethane to penetrate through holes was characterized. An attempt was made to measure the water permeability of the material.

Author: Steven Soltesz, Oregon Department of Transportation Research Group