Heat of Hydration Models for Cementitious Materials

Models are used to characterize the behavior of concrete exposed to in-place conditions. These models need to include methods to quantify the heat of hydration of cementitious materials. This article presents the formulation of a general hydration model for cementitious materials. The authors note that the degree of hydration characterizes the formation of hydration products as hydration progresses over time, and each concrete mixture has a unique degree of hydration development. The authors used semi-adiabatic calorimeter tests on 13 different concrete mixtures and with heat of hydration data from 20 different cement types to provide a convenient, indirect means of characterizing the formation of hydration products by measuring the heat released during hydration. Their hydration model incorporates the effect of following variables: cement chemical composition, cement fineness, supplementary cementing materials (Class F fly ash, Class C fly ash, and ground-granulated blast-furnace (GGBF) slag cement), mixture proportions, and concrete properties (density, thermal conductivity, and specific heat). The authors conclude that this model provides a reasonable and accurate representation of the heat of hydration development under different curing temperatures.