Hydration Study of Cementitious Materials using Semi-Adiabatic Calorimetry

Abstract

Accurate characterization of the temperature rise in a concrete element requires an estimate of the adiabatic temperature rise of the concrete mixture. Semi-adiabatic calorimetry is commonly used to provide an estimate of the heat generation characteristics of a concrete mixture because of the relative simplicity of the test. This study examines the sources of variability in semi-adiabatic calorimetry, and an estimate of the confidence limits of the test is calculated. Then, twenty concrete mixtures are investigated using semi-adiabatic calorimetry. Activation energy values are calculated for each mixture using isothermal calorimetry. The adiabatic temperature rise is then calculated. The following mixture properties are investigated: cement type, cementitious content, water/cementitious material ratio, coarse aggregate type (siliceous river gravel and limestone), mixture placement temperature, and the effects of selected supplementary cementing materials. The following factors were the most important to reduce the adiabatic temperature rise: reduced cement content, use of a lower-heat cement, such as a Type V cement type, reduced aggregate specific heat, and substitution of cement with Class F fly ash.