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.