Experimental modeling and quantitative evaluation of mitigating cracks in early-age mass concrete by regulating heat transfer

In mass concrete structures, significant thermal gradients and deformations are generated due to the exothermic hydration reactions of cement, and these deformations are further intensified by the constraints of structural boundaries, leading to potential cracking. This study aimed to investigate the mechanisms of hydration temperature rise control in mass concrete using temperature rise inhibitors and its impact on structural cracking. Field experiments and engineering cases were combined to analyze hydration temperature rise and early-age cracking of mass concrete, employing cement hydration theory and considering inhibitors and pipe cooling temperature control. Results revealed the application of inhibitors effectively prolongs the time required for the heat release from cement hydration to reach 30 kJ/kg initially. Adiabatic temperature rise control equations for hydration inhibitor-treated concrete, based on different delayed heat release times, were formulated. The application of inhibitors was found to achieve temperature peak control effects comparable to those of pipe cooling, contributing to the control of cracking. To mitigate thermal cracks, a careful balance of temperature control and curing strategies was identified as essential, ensuring cement hydration heat in a controlled and systematic manner throughout the structure. The optimization of the hydration gradient was shown to enhance the temperature control efficiency of inhibitors and to reduce the need for cooling pipe installation. The conducted modeling and calculations allowed to determine temperature control guidelines for constructing mass concrete structures, achieving control of the hydration rate across different concrete layers, homogenizing the overall structural temperature, minimizing thermal cracks, and reducing energy consumption.