New Model for Estimating Apparent Activation Energy of Cementitious Systems

This paper will discuss that some predictive models for concrete temperature development and strength depend on the application of the Arrhenius equation to characterize the progress of hydration, which in turn requires an apparent activation energy E(a) value to define the temperature sensitivity of the hydration reactions. Testing to determine E(a) can be very time-consuming and expensive. It would be useful to have a model that estimates E(a) for a given concrete mixture. To be broadly applied, such a model must account for the variable chemistry of cementitious systems. This paper describes the development of a model for E(a) using multi-variate statistics analysis of experimental hydration data from 116 cementitious mixtures. The model was also validated by an independent set of hydration data from six different cementitious mixtures. The model accounts for the effects of cement chemistry, supplementary cementitious materials, and chemical admixtures.