Hydration kinetics of cement-quicklime system at different temperatures

Highlights: • Hydration heat flow and hydration heat of cement lime system were measured at 20 °C, 30 °C and 40 °C. • Hydration process including NG, I and D of cement-lime system was simulated according to hydration kinetics model. • The dosage of CaO will influence the hydration kinetics of cement-lime system. • Curing temperature will influence the hydration kinetics of cement-lime system. -- Abstract: Hydration heat of cement-quicklime system were measured at 20 °C, 30 °C and 40 °C by isothermal calorimeter. Krstulovic Dabic kinetics model was used to simulate the hydration process of cement-quicklime system. The kinetics exponent, n, rate constant, K, were calculated and discussed. XRD and SEM were used to analyze the hydration process. Results indicate that the kinetics model could well simulate the hydration process of cement-quicklime system with a low CaO content including nucleation and crystal growth (NG), interactions at phase boundaries (I) and diffusion (D) but is not suitable for pastes with more than 30% CaO, especially the D process. With the increasing of curing temperature, the value of K increases and n decreases. The value of n and apparent activation energy for cement-quicklime system firstly decreases with increasing CaO content, then increases after the dosage of CaO excesses 20%.