Prediction of Adiabatic Temperature Rise of Concrete Containing Fly Ash Using On-Site Measurement and Multi-Scale Modeling

In this study, an experimental adiabatic temperature rise (ATR) measurement and a multi-scale analytical approach were investigated for concrete containing Class F fly ash (FA). A half-meter (0.5 m) insulated cube was developed to measure the ATR. ATR calorimetry was used to verify the applicability of the 0.5 m insulated cube. The ATRs were obtained by calculating the heat loss from the cube. Besides the insulated cube and adiabatic calorimetry, a multi-scale hydration model was programmed to predict the ATR from the chemical composition of the cementitious materials and mix designs. The model consists of two parts; the first part is for the Portland cement (PC) hydration reaction, and the second part is for the FA reaction. The analytical model was verified using ordinary PC and FA concrete mixes, and the ATR predictions compared well with the experimental measurements. The proposed methods proved to be a reliable alternative approach to obtain the ATR of a concrete mix containing FA. The developed 0.5 m insulated cube offers a more practical and economical approach for estimating the ATR while maintaining accuracy comparable to large-scale cubes, making it suitable for both field and laboratory applications. The study integrates on-site measurements with multi-scale analytical modeling to provide a better understanding of the hydration behavior and temperature development in FA-blended concrete.