On the initial stages of cement hydration

After the initial mixing of cement, an induction period occurs during which its consistency remains constant. Thickening occurs at the end of this per iod when the consistency is observed to increase very rapidly. In this pape r we propose a reaction-diffusion model for the hydration of tricalcium sil icate, a principal constituent of cement, which is believed to be responsib le for the initial development of its strength. Our model is based on the a ssumption that the hydration of cement can be described as a dissolution -p recipitation reaction. The mathematical solutions enable us to determine so me of the factors that control the length of the induction period and make predictions of the ionic concentrations which are in agreement with experim ental data.