| abstract |
A hardened cement-based mass having a corrosive metallic material embedded therein, or containing an aggregate reactive with an alkaline substance, is impregnated with an aqueous solution containing 1 to 50% by weight of a dissolved nitrite of an alkali metal or alkaline earth metal and 0.01 to 20% by weight of a dissolved organic silicon compound such as sodium methylsiliconate or potassium methylsiconate, or a dissolved or emulsified polymer thereof, or with a solution prepared by using an aliphatic alcohol having 1 to 3 carbon atoms, and containing 1 to 50% by weight of a dissolved nitrite of an alkali metal or alkaline earth metal and 0.01 to 20% by weight of an dissolved organic silicon compound such as methyltrimethoxysilane or ethyltrimethoxysilane, or a dissolved polymer thereof, and is allowed to dry in the air. Alternatively, the mass is coated with an unsolidified cement paste, mortar or concrete containing 1 to 25% by weight of a nitrite of an alkali metal or alkaline earth metal and 0.01 to 20% by weight of an organic silicon compound such as sodium or potassium methylsiliconate, or a polymer thereof, based on the weight of the cement which, e.g., the cement paste contains, and, e.g., the cement paste is allowed to harden in the air. |