| abstract |
The surface of an inorganic substrate comprising cement, concrete, gypsum or mixtures thereof is treated with a silicate solution or a silica sol comprising a monovalent alkali metal containing component, an ammonium containing component and a silica containing component at a molar ratio of 1:1 DIFFERENCE 10:4 DIFFERENCE 5000 corresponding to M2O:[R1R2R3R4N]2O: SiO2 wherein M is Li, K or Na; and R1, R2, R3 and R4 each represent a hydrocarbon group or an alkanol group. The underlying inorganic substrate thus has a modified surface layer thereon having a thickness of less than 50 mm, which functions to protect and prevent deterioration of the underlying surface of said inorganic substrate. |