Experimental study on coefficient of air convection for concrete mix of nuclear power plant

The setting and hardening of concrete is accompanied with nonlinear temperature distribution caused by development of hydration heat of cement. Especially at early ages, this nonlinear distribution has a large influence on the crack evolution. As a result, in order to predict the exact temperature history in concrete structures it is required to examine thermal properties of concrete. In this study, the coefficient of air convection for concrete mix of nuclear power plant, which presents thermal transfer between surface of concrete and air, was experimentally investigated with variables such as velocity of wind and types of form. From experimental results, the coefficient of air convection was calculated using equations of thermal equilibrium. From the previous prediction model for equivalent coefficient of air convection including effects of velocity of wind and types of form was verified. The coefficient of air convection obtained from experiment increases with velocity of wind, and its dependence on wind velocity is varied with types of form. This tendency is due to a combined heat transfer system of conduction through form and convection to air. From comparison with experimental results, the coefficient of air convection by this model was well agreed with those by experimental results