Dissolution–precipitation kinetics during C3S hydration: A holographic interferometry study
Abstract
Tricalcium silicate C 3 S has been widely employed in model systems to interpret the complex mechanisms of cement hydration. The present study aims at providing an accurate description of the dissolution rate of C 3 S by implementing a new approach based on holographic interferometry. We propose a protocol that allows the measurement of the pure dissolution rate constant of the C 3 S phase by experiments performed in supersaturated conditions with respect to C-S-H. In these experiments, a flat polycrystalline surface of C 3 S was monitored in a quiescent solution. The amount of calcium released within the holographic cell was measured and the aqueous solution composition was constrained to the C-S-H stoichiometry at the interface. An equilibrium approach was applied to assess interfacial pH, saturation indexes, and C-S-H precipitation at the experimental conditions. Providing the rate constant allowed tracing the rate law of the pure dissolution of C 3 S from far to close-to-equilibrium conditions.