Asymptotic homogenization of effective thermal-elastic properties of concrete considering its three-dimensional mesostructure

Abstract

Thermal-elastic properties, including the elastic modulus and coefficients of thermal expansion (CTE), are two crucial mechanical parameters in concrete design. However, the modeling of concrete structure is complex, and existing numerical models for the elastic modulus and CTE homogenization are established separately under mechanical and temperature load, leading to higher computational costs when both parameters are required. Moreover, the effects of aggregate morphology, imperfect interfaces, gradation, voids, and aggregate orientation on the concrete’s CTE are not investigated comprehensively. Therefore, an efficient algorithm for generating the concrete mesoscopic model with differently shaped aggregates and imperfect interfaces is proposed. Subsequently, by extending the thermal-stress method to the CTE’s homogenization, an asymptotic homogenization software platform for predicting the effective thermal-elastic properties of concrete is developed. Based on the suggested size of the representative volume element, the rationality of the established numerical models is validated by analytical models and experiments, followed by the analysis of the effect of concrete's mesostructure on its effecttive thermal-elastic properties. The results show that the imperfect interfaces, aggregate types, aggregate gradation, voids, and aggregate orientation have varying degrees of effect on the thermal-elastic properties of concrete. The effect of aggregate morphology can be neglected.