Abstract
This study deals with the difference in the initial hydraulic properties of C11A7· CaF2 and C3A3 CaSO4 in the presence of Ca (OH) 2 and CaSO4 at different temperatures. The hydration process of the C3A3·CaSO4-Ca (OH) 2-CaSO4 system (C3A3·CaSO4 system) can not distinctly be classified into the dormant period, acceleratory period and decay period like that of the C11A7·CaF2-Ca (OH) 2-CaSO4 system (C11A7·CaF2 system) and the temperature dependence of the C3A3·CaSO4 system by hydration is larger than that of the C11A7·CaF2 system. The hydraulic properties of the C3A3·CaSO4 system, in which the dormant period is obscure, are closely concerned with the higher hydraulic activity of C3A3·CaSO4 at least beyond 20°C. These results were explained in terms of the difference in the rate-determining step of their hydration processes. Subsequently, the morphology of ettringite is also dependent on the difference in the hydration process.
