Chemical alteration of calcium silicate hydrate (C-S-H) in sodium chloride solution

The effect of sodium chloride on the chemical alteration of calcium silicate hydrate (C-S-H) was measured and discussed. The release of calcium from C-S-H was increased as the concentration of sodium chloride in the solution increased. It was observed that sodium sorbed onto the C-S-H phases and some sodium replaced calcium in C-S-H so that the release of calcium was enhanced. An integrated modelling approach employing an ion-exchange model and an incongruent dissolution model of C-S-H is developed. It reasonably and accurately predicted the release of calcium from C-S-H in sodium chloride solution by considering cation exchange and the effect of the ionic strength on the solubility of C-S-H.