Process for lining canals, ditches and pipes with a non-sagging polyurethane/geofabric composite

A surface of a canal, ditch or pipe is lined with a polyurethane/geofabric composite. A non-sagging polyurethane composition is applied to the canal, ditch or pipe surface, a geofabric is contacted with that surface in a manner such that the geofabric becomes impregnated with the non-sagging polyurethane composition which cures to form a polyurethane/geofabric composite. The non-sagging polyurethane is a reaction product of a polyisocyanate, a high molecular weight polyhydroxyl compound and a compound having at least 2 amino groups. A low molecular weight diol or triol, filler and catalyst are optional components. These composites are particularly useful in lining cracked or broken concave or angled surfaces.