Multi-scale hygro-thermo-mechanical simulation of concrete drying shrinkage damage

Predicting drying shrinkage-induced damage in concrete necessitates a multi-scale approach. This study introduces a comprehensive hygro-thermo-mechanical modeling framework to investigate this damage from the molecular to the meso-scale. At the molecular level, the classical density functional theory (cDFT) is adopted to model the water-calcium silicate hydrate (C-S-H) layer interactions. At the micro-scale, thermodynamic models, informed by the cement paste's pore size distribution (PSD), simulate its desorption and shrinkage behaviors. This molecular and micro-scale information is then integrated to predict moisture transport and resulting shrinkage strains at the meso-scale. The internal stresses arising from these shrinkage strains subsequently drive drying shrinkage-induced damage, the evolution of which is characterized at the meso-scale by a thermodynamically consistent hygro-thermo-mechanical phase field model. Thermal and mechanical processes are simulated using the properties of sufficiently mature concrete, ensuring simplicity without compromising accuracy. The predictive capabilities of this multi-scale framework are validated through representative simulations compared against experimental data, demonstrating its accuracy across the different scales. © 2025 Elsevier Ltd.