Desiccation shrinkage of cementitious materials as an aging, poroviscoelastic response

This paper describes and evaluates a new model that utilizes aging poroviscoelasticity for predicting the shrinkage of cementitious materials induced by loss of moisture from the pore structure (i.e. desiccation). The new model incorporates well-accepted mechanisms for desiccation shrinkage and accounts for the effect of changing concentrations of dissolved species in the pore fluid. Additionally, the model is used to interpret viscoelastic behavior during the drying process via comparisons of model predictions with measured shrinkage of hardened portland cement paste. It was found that while a poroelastic model under predicts the measured shrinkage, the poroviscoelastic model significantly over predicts the shrinkage unless intrinsic aging of the C–S–H gel is included in the model.