Hygro-thermo-chemical modeling of high performance concrete. I: Theory

This study deals with the formulation, calibration, and validation of a new hygro-thermo-chemical model for high-performance concrete (HPC) suitable for the analysis of moisture transport and heat transfer at the early age and beyond. In Part I of this study the theoretical formulation is presented and discussed in detail. Classical macroscopic mass and energy conservation laws are written by using humidity and temperature as primary variables and by taking into account explicitly various chemical reactions, such as cement hydration, silica fume reaction, and silicate polymerization. The effect of cement hydration is modeled through the classical concept of hydration degree. Silica fume reaction and silicate polymerization are modeled by introducing the degree of silica fume reaction and the concentration of silicate polymers, along with their evolution laws. The present model can simulate early age phenomena, such as self-heating and self-desiccation, with great accuracy. Numerical implementation, calibration and validation of the model by comparison with experimental test data are postponed to Part II of this study [Di Luzio G, Cusatis G. Hygro-thermo-chemical modeling of high performance concrete. II: Numerical implementation, calibration, and validation. Cem Concr Compos, in press].