Abstract
The application of the Arrhenius equation to characterize the progress of cement hydration requires the use of an apparent activation energy () value to describe the temperature sensitivity of the combined hydration reactions. Supplementary cementitious materials (SCMs) such as fly ash, ground-granulated blast-furnace slag, and silica fume are an integral part of most concrete mixtures, but their impact on has not been fully explored for a wide range of cement and SCM compositions and replacement levels. This information is important in order to predict heat from the hydration of concrete or strength development using the “maturity method.” This paper examines the effects of SCMs on the apparent activation energy (). It was observed that increasing amounts of Class F fly ash and silica fume generally lowered , but the effects of slag and Class C fly ash were dependent on the composition of the cement, particularly the aluminate, alkali, and soluble sulfate contents.