ABSTRACT
Abstract Hydration processes and the associated microstructural development of cement-based systems is accompanied by a number of volume changes. One of these volume changes originates from changes in the pore system itself and of the state of water in the pore system, i.e. a decrease of the vapour pressure and the associated role of surface tension in the pore system. In this contribution it will be shown how the hydration process, the microstructural development and the associated volume changes, which are supposed to be correlated to the relative humidity in the pore system, can be modelled numerically. First the basic principle of the model for hydration and microstructural development is briefly explained. Subsequently it is explained how this model is used as a basis for numerical modelling of volume changes associated with the changes in the state of water in the pore system. It is briefly shown how thermodynamic equilibrium in the continuously changing pore system is modelled. Changes in the relative humidity and in the capillary water and associated volume changes are calculated for isothermally cured mixes. Numerical and experimental results obtained for pastes and for one concrete mix are compared. Keywords: Hydration, microstructure, self desiccation, volume changes, numerical modelling.
