Hydration of cements based on metakaolin: thermochemistry

Metakaolin is a supplementary cementitious material with pozzolanic properties. Its activation by calcium hydroxide. sulphates and alkali hydroxide is reported. The extent and kinetics of various competing reactions at an early period of hydration were investigated using calorimetry, supplemented by XRD and DTA data. Theoretical values. obtained for the total heat evolutions using classical thermodynamic methods, were in satisfactory agreement with observed values. The results are correlated with the mechanisms of early hydration.