89240 ⎘
After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone; Coating or impregnating e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements,; Non-chemical aspects relating to the substrate being coated or impregnated Superficial melting of the substrate before or during the coating or impregnating step