A Case Study on Heat of Hydration of a Mass Concrete Foundation Containing Slag Cement

In this study, the thermal performance of a large-scale foundation constructed with self-consolidating concrete incorporating slag cement was systematically investigated. The primary aim was to regulate the concrete temperature during and after placement, and to manage peak thermal gradients in order to mitigate the risk of thermal cracking. The foundation, with an approximate volume of ۲۰۰ cubic meters, was instrumented for temperature monitoring using a data logger and thermocouples embedded at four different depths. The concrete mix was engineered with a ۳۵% cement replacement by slag and a water-to-cementitious materials ratio of ۰.۴. Polyethylene foam insulation was applied as an external thermal cover for the concrete surface. Over a monitoring period of ۵۷ days, the recorded data indicated a maximum concrete core temperature of ۷۰.۷°C and a peak thermal gradient of ۳۰.۶°C on the first day after casting. The timely application of polyethylene insulation facilitated a gradual reduction in the thermal gradient, which decreased to ۹.۱°C by the time the insulation was removed. These findings underscore the critical importance of selecting appropriate materials (such as slag), employing an optimized mix design, and implementing timely insulation measures to effectively control surface temperatures and thermal gradients in mass concrete. Collectively, these strategies play a pivotal role in reducing the risk of thermal cracking and enhancing the durability of large-scale concrete structures.

Keywords:

Self-Consolidating Concrete (SCC) , Mass Concrete , Thermal Gradient , Thermal Monitoring