Apparent Activation Energy of Cement Blended with Rice Husk Ash

The hydration kinetics of cement depends on the reaction temperature. An issue related to the effects of curing temperature on cement hydration is the apparent activation energy (Ea). The effect of Rice husk ash (RHA) on Ea is still not clear. This paper studies the Ea of Portland cement blended with RHA using isothermal calorimetry. Based on the experimental data, the Ea of RHA blended cement was first calculated with the hydration process. Besides, the mean Ea was also calculated according to the modified ASTM C 1074 method. In this study, it was observed that the Ea depends on the degree of hydration, water to binder ratio, temperature, and the RHA replacement. The variation of Ea along with the degree of hydration reflects the change in the mechanism during the hydration process.