Analysis of concrete structures with hydration heat and differential shrinkage

Abstract

In this dissertation, to improve the current method of predicting thermal stresses and to develop analysis program inclusive of coupled hydration heat and differential drying shrinkage, a series of experiments and numerical analysis were performed. Relating to thermal stresses, thermal properties of concrete (i.e., thermal conductivity and the heat transfer coefficient) and the heat generation model were investigated to improve the predicted temperature distribution accuracy. And the analysis method for the behavior of concrete after cracking was described. In addition to the numerical prediction, the new device measuring thermal stresses was developed. For the coupled stress due to hydration heat and differential drying shrinkage, the mutual relationship between heat transfer and moisture diffusion was numerically investigated. Also, three-dimensional analysis program for the coupled stress was developed. From the experiment for the thermal conductivity of concrete with seven parameters, the results show that aggregate volume fraction is a main parameter on the conductivity of concrete. Based on the experimental results, the prediction model was proposed to accurately estimate the thermal conductivity of concrete. The proposed relationship correlates test results by indicating the sample correlation coefficient of 0.95. According to the experimental results for the heat transfer coefficient, the effect of wind velocity on the heat transfer coefficient is larger than that in previous models and varies with form types. Based on this experiments and the theoretical background for flow convection, the general prediction model including properties of formwork as well as wind velocity was proposed. The heat transfer coefficient obtained by the proposed model well agrees with those from the experiments. To predict the generation of hydration heat, the hydration heat model is adopted. This hydration heat model is more reasonable than the adiabatic temperature ris...