Early Hydration Kinetics of Cementitious Materials Containing Different Steel Slag Powder Contents

This study measures the hydration heat emission rate and quantity of cementitious materials containing 10%, 20%, 30% and 40% of steel slag (SS) powder at 298 K, calculates the kinetic parameters such as the reaction rate constant k, the degree of hydration α, and the order of reaction n according to the Krstulovic-Dabic hydration kinetics model, and discusses the influence of SS content over the hydration reaction and mechanism of cementitious materials.Results show that, with the increase in SS content, the hydration heat emission quantity decreases.The hydration process of cementitious materials containing different SS contents involves three stages, namely, nucleation and crystal growth (NG), interactions at phase boundaries (I), and diffusion (D).The Krstulovic-Dabic model can effectively simulate the hydration process of SS-based cementitious materials prepared with all-solid wastes.With the increase in the SS content, the hydration reaction induction period prolonged and the generation of hydration products is slowed down.At the early stage of hydration, NG is the controlling factor, which is gradually replaced by I as the hydration degree increases, and eventually by D when the reaction reaches the final stage.