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 with out silica fume additions, have been prepared and characterized with r espect to their adiabatic heat signature. The measured responses are c ompared with predicted values from the NIST 3-D cement hydration and m icrostructural model, which has been modified to incorporate the pozzo lanic reaction of silica fume and to simulate hydration under adiabati c conditions. The latter modification is based on the activation energ ies and heats of reaction for the hydration and pozzolanic reactions a nd the heat capacity of the hydrating concrete mixture. For concretes with and without silica fume, the agreement between predicted and meas ured response is always within about five degrees Celsius. For concret es with silica fume, using an appropriate stoichiometry for the pozzol anic C-S-H is critical in matching the long-term (4 to 8 day) experime ntal temperature rise behavior. (C) 1998 Elsevier Science Ltd.