Modeling Shrinkage of Portland Cement Paste

Abstract

Based on the theories of poromechanics and mechanics of composites, a multi-scale constitutive model is developed for hardening cement past shrinkage simulation. The driving force of autogenous shrinkage is considered capillary stress. The model also considers applied pressure, which for some applications can be another driving force of shrinkage. For the elastic properties of hardening cement paste, a multi-scale and micromechanical model is first formulated; then the model considers calcium-silicate-hydrate's (C-S-H's) nonlinearity and creep behaviors, which are of great importance for cement paste shrinkage. C-S-H's time-dependent properties are back-calibrated against cement paste autogenous shrinkage experimental results. Final verification of the model is done through reproduction of both elastic properties and autogenous shrinkage of different cement pastes, and other experimental data are compared with the results.