Abstract
Calcium oxide and silica-gel mixtures milled by a planetary mill was subjected to heating and watering operations. The milled and heated mixtures and their hydration behavior were investigated by X-ray diffraction and differential thermal analyses. Dicalcium silicate (C2S) is formed by heating the mixture milled for 30 minutes or more at about 750 K, while it appears at 1170 K in the case of the unmilled mixture. Amount of the C2S formed at the relatively low temperature is increased with an increase in milling time of the mixture. The crystallizing temperature appeared at 1170 K is shifted towards the lower side with an increase in milling time, and comes close to 750 K. The crystallinity of C2S hydrates formed by adding water to the heated mixtures after milling operation is inferior to that to the milled one without heating.
