Computational Modeling of the Time-dependent Behavior of Cementitious Materials

Abstract

Finite element procedures combined with microstructure development modeling are integrated to quantitatively predict the viscoelastic/viscoplastic relaxation of cement paste due to intrinsic calcium silicate hydrate viscoelasticity/viscoplasticity and microstructure evolution. The combined models are implemented in a computational routine to predict time-dependent stress and strain fields in cement paste. Besides predicting the time-dependent viscoelastic/viscoplastic properties of cement paste, the early-age desiccation shrinkage of cement paste is also computationally simulated utilizing this modeling approach. The model simulations suggest that inherent viscoelastic deformation caused by calcium silicate hydrate might not necessarily be the primary mechanism leading to the overall early-age time-dependent behavior of cement paste. The effect of time-dependent dissolution of load-bearing phases due to either the hydration reaction or the application of stress/strain can be substantial and should be considered as a significant mechanism for the apparent viscoelasticity/viscoplasticity of cement paste.