Method for the repair of existing manholes using elastomeric materials

Abstract

This invention relates to a method of repairing existing manholes and similar structures by applying a fast-curing elastomeric material using spray techniques whereby a homogeneous, non-porous, and monolithic coating or lining is formed. The fast-curing elastomeric material can be applied directly to existing substrates, which may comprise of concrete, brick, tile, mortar, and metal surfaces normally found in sewer manholes and catch basins, sewer and drainage pipes, parking decks, bridge piers and footings, holding ponds, bridge trusses, culverts, gratings, and the like and does not require any formwork. More preferably, the substrate surfaces are first cleaned and primed to improve the bond of elastomeric coating to the substrate. The most preferred primer is an aqueous solution of silane, preferably containing 10% to 30% silane. The elastomeric coatings provide effective surface protection against water infiltration, wear, and corrosion and can be applied in a single operation to horizontal, vertical, and overhead surfaces. The elastomeric materials are prepared by initiating the reaction of an isocyanate-terminated compound or polymer with an amine-terminated polymer or an aliphatic or aromatic diamine immediately before applying the elastomeric material to the surface to be coated. Preferably the reactive component (i.e., isocyante-containing and amine-containing materials) are mixed directly in the spray gun used to apply the elastomeric material.