Benefits of porosity‐dependent moisture retention modelling for predicting autogenous shrinkage of concrete

Abstract

Concrete can be modelled as a porous medium, the pores being filled with moist air and water. In equilibrium, the water content in the pore system is related to the ambient humidity by a constitutive law like relation, the so‐called sorption isotherm. The shape of the sorption isotherm depends on the pore size distribution in the porous medium and will therefore change due to hydration. This paper reviews the benefits of a recently proposed and calibrated porosity dependent desorption isotherm for maturing concrete. Special emphasis is placed on the resulting improvements for predicting the evolution of the autogenous shrinkage strain in multiphase modelling of maturing concrete. They are highlighted by a comparison to results obtained with a multiphase model based on a moisture retention function which is independent of the actual value of porosity.