Influence of environmental parameters on thermal stresses

Non-uniform temperature distributions (thermal gradients) in concrete structures are a cause of thermal cracks. It is well known that concrete cracks pose serious problems for concrete structures from functionality and durability viewpoints, which may result in shortening of the useful lives of these structures. Techniques for estimating the occurrence of thermal cracks in concrete structures have been established and used in practice. In order to predict a highly reliable thermal stress, accurate thermal analysis considering environmental effects at concrete surface is required. A boundary model of the concrete surface, considering environmental parameters to predict accurate concrete temperature, is proposed in this paper. The effectiveness of the model has been confirmed by field tests using concrete specimens. Fürthermore, the results from thermal stress analysis using the proposed model have been compared with the thermal stresses obtained using the ordinary boundary conditions with convective heat transfer.