Predicting the evolution of mechanical and diffusivity properties of cement pastes and mortars for various hydration degrees – A numerical simulation investigation

Predicting the time-dependent performance of cement-based materials during hydration has been a challenge to many researchers from all over the world. In this context, numerical approaches present many advantages and can be considered as the only real alternative to obtain the properties starting from the microstructure. aper presents a multi-scale strategy based on the development of the MuMoCC platform (Multi-scale Modelling of Computational Concrete). A combination of the NIST cement hydration model (CEMHYD3D) and the FE software Abaqus is proposed and applied to study the diffusion and mechanical behaviours of cement-based materials during hydration. The evolution of the effective diffusion coefficient, the elastic modulus and the compressive strength of mortar according to the capillary porosity and the degree of hydration is put into evidence. For mechanical computations, both elastic and inelastic behaviours are considered. Firstly, the methodology was applied to a water-to-cement ratio (w/c) 0.4 cement paste and mortar. Then and based on numerical simulations, a set of simplified formula relating the main engineering parameters of transport and mechanical behaviour to capillary porosity is proposed and addressed to researchers involved in modelling at meso-scale and who need input data coming from the cement paste scale.