Simulation of Low-Calcium Fly Ash Blended Cement Hydration

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.The authors are grateful to the reviewers for their valuable comments. This work was supported by Sustainable Building Research Center Hanyang University, which is supported the SRC/ERC program of MOST (#R11-2005-056-04003-0) and a grant (06-CIT-A02: Standardization Research for Construction Materials) from the Construction infrastructure Technology Program funded by the Ministry of Construction & Transportation of the Korean government