New developments in understanding the chemistry of cement hydration

Abstract

Portland cement is based on calcium silicates with lesser amounts.of calcium aluminates. Its reaction with water, which is responsible for strength development, is a complex process involving the precipitation of hydration products in colloidal gel and crystalline forms. This paper describes the microstructural development of the hydrates the structure of colloidal C—S—H gel, which is the main hydration product, the kinetics of hydration and the aqueous solution chemistry of cement pastes and pastes made with pure C ₃ S. Theories relating to the mechanism of cement hydration are examined and these are discussed in terms of studies of the effect of accelerating and retarding admixtures for cement.