Experimental study on the thermal convection behaviour of concrete material in service environments

Concrete is a kind of common building material with many advantages and widely used in civil infrastructures. Concrete has the qualities of uneven, anisotropic, large dispersion and thermal inertia, therefore, it is very difficult to accurately determinate its thermophysical properties. The lab testing conditions are much different to the service environments of structures. The inverse method using field measurements affected by so many factors and uncertainties decreases the reliability of results. In this study, the heat convection behaviour of concrete in natural service environments is investigated using specimen experiments. A special testing system is designed and established. It includes a small size thermal insulated cuboid tank, concrete specimens, temperature and wind speed measuring and collection. The heat convection coefficient of concrete in natural environments is investigated taking account of different wind speed and roughness of concrete surface. The results indicate that the roughness of specimen surface has considerable effects on the heat convection coefficient. Based on the measurements, the relationship between heat convective coefficient and wind speed of concrete is regressed using linear equation. Comparing with other literature, the results of this study is reasonable and reliable.