Hydrothermal reactions of dicalcium silicate and silica

The kinetics of hydration of five C₂SS cements at 0.83C/S were studied at 175 to 300°C. CSH(I) formed as the initial hydration phase in four cements and tobermorite in the other. Amounts of 1.32 and 1.74% CO₂ in two cements caused total replacement of xonotlite by scawtite, while 0.34 and 0. 37 CO₂ yielded negligible amounts of scawtite (if any). The equilibrium products in the two cements were scawtite and gyrolite at 175 and 200°C and scawtite and truscottite at 250 and 300°C.