Highway surface - with polyurethane foam coat on the plastic film covering the polyurethane foam insulation

摘要

An insulating layer of hard polyurethane foam is sprayed beneath the cast concrete of bitumen surface with the foam covered by a plastic film as in parent patents, the improvement being that a thin layer of polyurethane foam reaction mixture is sprayed on top of the plastic film. Pref. the hot bituminous material is poured directly onto this protective layer to form the bitumen surface.