Frothing technics with mixed polyurethane materials have been widely used in the field of civil engineering. Polyurethane has many properties, such as frothing quickly, stronger viscidity and better elasticity. Having been frothed and vulcanized, polyurethane with other hard granules can form a new kind of backfill materials which have the higher initial strength. Based on the properties of polyurethane above, the frothing technic of polyurethane materials can be applied to consolidation and backfill of concrete and roadbed structure. In this paper, on the base of the experimental research about the materials’ properties, a test simulating an actual consolidation of subsoil was processed. The stable backfill substance used as base of pavement can be formed quickly by frothing of polyurethane in the pore space of gravels. The surface of pavement can be made from gravels and some certain polyurethane. It took 2 hours to backfill the base and to make the surface. Immediately, the loading test including static and impact load was taken. The result of the test indicated that the mechanical properties of surface and base made up of polyurethane composite materials can satisfy certain standards and specifications.