The utility of a bimolecular expression to describe the heat generation and temperatures in curing Class HP concrete

For several days after concrete is poured, atmospheric conditions influence the hydration reactions of concrete's binder components and so may influence its long-term durability. Accurate concrete temperature and moisture forecasts would help engineers determine an optimal pour time. Some existing curing concrete models include complicated chemistry and/or microstructure development parameterizations or do not allow for mix design changes. A bimolecular heat generation expression that is simple but sufficiently detailed to account for mix design changes was improved for Class HP concrete. Analysis of published calorimetry data and those determined in this study indicated that a second-order formulation adequately describes the heat generation. Class HP binder has an activation energy of ∼ 35 kJ mol^-1. After 72 h, Class HP pastes evolved 250-280 kJ kg^-1. A method to account for the effect of retarders on Stage II length and Stage III hydration rates was developed. A curing concrete bridge model with the bimolecular expression predicted concrete temperatures to within 2 °C of observed temperatures and reasonable 72-h hydration fractions (∼ 0.6).