Investigation of the CaO–Al₂O₃–SiO₂–CaSO₄–CaCO₃–H₂O system at 25°C by thermodynamic calculation Available to Purchase

The phase diagram of the CaO–Al₂O₃–SiO₂–CaSO₄–CaCO₃–H₂O system relevant to cement has been calculated at 25°C and 1 bar pressure. It is composed of 331 stable phase assemblages in equilibrium with the aqueous phase and contains 30 invariant points with 15 solids. Thaumasite appears to be a stable phase with a wide stability domain. Compared to ettringite, thaumasite is stable to lower pH and generally demands higher sulphate concentrations to be stable.