Method for manufacture of polymer-impregnated hollow concrete product

A method for the manufacture of a polymerimpregnated hollow concrete product, comprising the steps of (a) placing a concrete mix in a frame capable of withstanding high temperature and high pressure and shaped to form a product defining a hollow portion, (b) tightly closing the frame containing the concrete mix to mold the concrete mix into the hollow concrete product, (c) heating the tightly closed frame until the molded concrete contained therein has been cured, and, after strength has developed in the cured molded concrete, (d) drying the cured molded product and then deaerating the cured product in the frame interior, (e) supplying a monomer to the hollow portion of the deaerated concrete product within the frame, (f) applying pressure on the frame interior until the monomer has been diffused in the fine voids of the concrete product, and (g) heating the monomer entrapped in the concrete product in the frame until the monomer has been polymerized.