Kinetics and Mechanisms of Hydrothermal Reaction of Granulated Blast Furnace Slag

Kinetics and mechanisms of hydrothermal reactions of the systems slag-lime-water (I) and slag-quartz-lime-water (II) have been studied. In the initial stage of reaction in system (I), nearly amorphous calcium silicate hydrate with low lime content was formed and continued to grow in strength. Formation of hydrogarnet (3CaO·Al2O3·SiO2·4H2O) accompanied by the crystallization of calcium silicate hydrate caused a reduction in strength. In the reaction in system (II), a product with high lime content was formed which was then changed into a low lime product after complete consumption of free lime. Slag was highly reactive but inhibited reaction of quartz, especially during the initial stage of the hydrothermal solidification process. The rate of hydrothermal reaction as well as the characteristics of the products change considerably with temperature.