The Influence of Microsilica on the Course of Hydration of Monocalcium Aluminate

摘要

Calorimetric curves of mixtures of CA and microsilica show an intermediate peak of heat evolution after about 1 hour of hydration. The extent and the time of occurrence of the intermediate peak is influenced by temperature as well as by the amount and quality of the silica fume used. Experiments have shown that this peak is connected with a sharp increase of the [Al(OH)_4]~- concentration in the liquid phase of the hydrating paste and with the crystallisation of a small amount of calcium aluminate hydrates. A possible explanation of this behaviour, which influences the setting behaviour of Low Cement Castables (LCC) is given.