Kinetic modeling of calcium aluminate cement hydration

The hydration of iron-rich calcium aluminate cement (CAC) has been investigated by differential calorimeter and quantitative powder X-ray diffraction (QXRD). A simplified stoichiometric model of early age CAC hydration based on reaction schemes of the principal mineral monocalcium aluminate was employed. The CAC characteristic feature of retardation of nucleation and growth mechanism with temperature requires employing more than one kinetic mechanism to describe the resulting complex hydration kinetics. This paper proposes a single equation kinetic model of CAC hydration which comprises simultaneously three main mechanisms: nucleation and growth, chemical interaction and mass transfer. A gradual change between kinetic mechanisms was grasped with a reasonable inter-dependency of the kinetic parameters. The overall hydration kinetics was described relative to the amount of the both reactants, cement and free water.