Techniques for Retarding the Penetration of Deicers into Cement Paste and Mortar.

摘要

Several techniques were tried for limiting the penetration of deicing salts into concrete and thereby preventing the corrosion of reinforcing steel in concrete bridge decks caused by the presence of chlorides. Factors affecting the penetration of deicing salts were studied with hydrated cement pastes and mortars as the penetration medium. Salts tested were,in increasing order of degree of penetration:ammonium fluoride,sodium chromate,calcium chloride,sodium chloride,ammonium chloride,and aluminum chloride. The most effective retardation technique was impregnation with methyl methacrylate monomer and subsequent polymerization by irradiation. Part of the investigation also included efforts to develop means for reducing dangerous chloride levels already existent in concrete. A back-flushing technique was effective in reversing chloride penetration to a limited extent and efforts in this direction are being continued. (Author Modified Abstract)