Prediction of Adiabatic Temperature Rise in Conventional and High-Performance Concretes Using a 3-D Microstructural Model

A series of conventional and high-performance concretes, with and without silica fume additions, have been prepared and characterized with respect to their adiabatic heat signature. The measured responses are compared with predicted values from the NIST 3-D cement hydration and microstructural model, which has been modified to incorporate the pozzolanic reaction of silica fume and to simulate hydration under adiabatic conditions. The latter modification is based on the activation energies and heats of reaction for the hydration and pozzolanic reactions and the heat capacity of the hydrating concrete mixture. For concretes with and without silica fume, the agreement between predicted and measured response is always within about five degrees Celsius. For concretes with silica fume, using an appropriate stoichiometry for the pozzolanic C-S-H is critical in matching the long-term (4 to 8 day) experimental temperature rise behavior.