Methods of reducing hydroxyl ions in concrete pore solutions

Abstract

Methods of reducing hydroxyl ions in concrete pore solutions are provided. Such methods are useful in providing resistance to gels which form in concrete due to the alkali-silica (ASR) reaction. The methods comprise, in one aspect, adding a salt, in aqueous or solid form, to the concrete, the salt having a cation higher in valence than the anion. In other aspects, the methods of the present invention comprise adding an acidic phosphate or a silicon-containing alkoxide to the concrete. All of the above methods are useful in reducing hydroxyl ions in concrete. Such methods can be used to resist ASR in fresh concrete, in concrete that is setting, or in hardened concrete. Methods are also provided for mitigating ASR while simultaneously healing cracks in concrete or bonding new concrete to existing concrete. The methods involve reacting an Si-containing alkoxide with a source of reactive calcium to produce calcium silicate hydrate.

Dependencies are inferred from the claim text.