Simulation of Low-Calcium Fly Ash Blended Cement Hydration

Abstract

Low-calcium fly ash (FL) has been widely used as a mineral admixture in normal and high-strength concrete. Hydration of cement blended with fly ash is much more complex than ordinary portland cement because of the pozzolanic activity in an alumino-silicate glass phase in fly ash. This paper presents a kinetic hydration model that is based on a multi-component concept and can simulate hydration of cement-FL blends. The proposed model starts with a mixture proportion of concrete and considers both portland cement h hydration and pozzolanic activituy. By applying the proposed model, this paper predicts the following properties of hydrating cement-FL blends as a function of hydration time: reaction ratio of fly ash, calcium hydroxide content, heat evolution, porosity, chemically bound water, and the development of the compressive strength of FL-concrete. The prediction results showed good agreement for the results of the experiment performed in this study.