A multiscale model for predicting the coefficient of thermal expansion of concrete

The coefficient of thermal expansion (CTE) of concrete is one of the important properties that are responsible for the thermal cracking of concrete structures. To reveal the essence of thermal expansion and predict the CTE accurately, this paper establishes a multiscale model for predicting the drained and undrained CTEs of concrete according to the microstructure based on the theory of continuum micromechanics. The microstructure of concrete is quantitatively analyzed according to the raw materials and degree of hydration. The CTEs are homogenized level by level from calcium silicate hydrate to cement paste, cement mortar, and concrete. Given the initial information of concrete, the CTEs can be predicted by the model. The experimental data of concrete from the literature validated the applicability of the proposed model. The influence mechanism of factors on CTEs can be explained by the influence on the microstructure of concrete. The model has good potential in optimizing the material design of concrete to obtain a lower CTE to minimize the risk of thermal cracking.