Effect of material of post-cooling pipes on temperature and thermal stress in mass concrete

Abstract

In this study, the effects of three different types of materials of post-cooling pipes on thermal stress and temperature gradients in mass concrete were investigated numerically. It was found that, of the three types of cooling pipe materials observed in this study, steel pipes caused the fastest cooling and the lowest concrete temperature, followed by polyethylene (PEX) and polyvinyl chloride (PVC) pipes. The temperature difference only occurs at locations less than 100 m from the cooling water inlet. The concrete temperatures obtained using a steel cooling pipe can reach temperatures 70% and 36% lower than those obtained using PVC and PEX cooling pipes, respectively. Compare to PEX and PVC cooling pipes, the steel cooling pipe can reduce the risk of cracking associated with the expansion of the core region and the shrinkage of the surface of the concrete. However, the steel cooling pipe increases the risk of cracking near the cooling pipe, where the tensile stress that occurs due to the use of steel pipes can reach values 25.3% and 12.7% higher than those occurring due to the use of PVC and PEX pipes, respectively. In high temperature regions, expansion of PEX and PVC pipes causes an increase in thermal stress, especially in the area near the cooling pipes.