Predicting the time-dependent hydro-thermo-mechanical properties of cement-based materials based on thermodynamic and multi-scale modeling

Studying the performance evolution of cementitious materials is of great significance for a better understanding of the durability and prediction of the service life of the concrete structure. This paper develops a model to predict the time-dependent effective mechanical, transport, and thermal properties of cement-based materials based on the volume partitioning scheme and multi-scale homogenization method. In the volume partitioning scheme, the thermodynamic modeling is coupled with a cement hydration kinetics model and a microstructure model for two types of calcium silicate hydrates (C-S-H) to calculate the time evolution of the volumes of gel pores, capillary pores, hydrates, and residual cement minerals in the hydrated cement system. In the multi-scale model, a simplified representation of the microstructure of cement-based materials is presented. The effective macroscopic properties of cement-based materials are predicted from their microstructure by combining Self-Consistent (SC) and Generalized Self-Consistent (GSC) schemes. Finally, the predictions are compared with experimental data from the literature, showing a good agreement.