Prediction of the heat of hydration of fly ash concrete by adiabatic temperature rise test and regression analysis

This paper deals with the proposal of a model that can predict the heat of hydration of concrete containing fly ash and the adiabatic temperature rise test results that are the basis of the model. For the adiabatic temperature rise tests, a total of 12 concrete mixtures were prepared with varying percentages of fly ash replacement and varying ratios of water–cementitious materials (w/cm). The test results indicate that the replacement of fly ash significantly reduces the adiabatic temperature rise and delays the early hydration of fly ash-blended cements. Additionally, w/cm was found to influence not only the maximum adiabatic temperature rise but also the slope of the temperature rise. Therefore, a regression analysis was conducted to propose three parameters (hydration time, hydration slope, ultimate degree of hydration) for the heat of hydration model of concrete containing fly ash. The developed heat of hydration model was validated using test data. Models that did not consider w/cm, similar to those proposed by other researchers, failed to accurately predict the test results. However, the final model developed, which incorporates w/cm, accurately predicted the test results, as confirmed through this study.