Simulation of temperature rises in hardening Portland cement concrete and fly ash blended concrete

Portland cement is the most widely used cement in the world. To contribute to the sustainability of the construction industry, industrial by-products from the combustion of coal, such as fly ash, are being widely used as mineral admixtures in normal and high-strength concretes. Owing to the pozzolanic reaction between calcium hydroxide and fly ash, the hydration of cement containing fly ash is much more complex than that of Portland cement. By considering the production of calcium hydroxide in cement hydration and its consumption in the pozzolanic reaction, a numerical procedure is proposed to simulate the hydration of concrete containing fly ash. The numerical procedure includes two sub-components - a cement hydration model and a fly ash reaction model. The heat evolution rate of fly ash concrete is determined from the contributions of the cement hydration and the pozzolanic reaction. Furthermore, the temperature history in hardening blended concrete is evaluated by combining the proposed numerical procedure with a finite-element method. The proposed model is verified through experimental data on concrete with different water to cement ratios and mineral admixture substitution ratios.