Effect of Piped Water Cooling on Thermal Stress in Mass Concrete at Early Ages

Abstract

The heat evolved during the hydration process may not dissipate properly due to the large size and poor thermal conductivity of mass concrete. Embedded cooling pipes of circulating water are generally used for heat removal from the interior of the concrete mass. This study experimentally shows that forced cooling helps reduce the interior temperature significantly; however, it leads to a reverse thermal gradient around the cooling pipe. This paper conducts a three-dimensional finite-element simulation of the hydration heat in concrete with a forced cooling system, modeling the circulating water with three-dimensional elements with diffusion and dispersion properties which accurately predict the experimentally observed temperature profile. Finite-element analysis also indicates the presence of high thermal stresses in concrete near the cooling pipe, mainly due to the extreme temperature gradient and temperature fluctuations. The results suggest a careful monitoring of heat removal using forced cooling to avoid a large thermal gradient and the likelihood of cracking.