Computational homogenization of effective permeability in three-phase mesoscale concrete

Concrete is modeled on the mesoscale as a heterogeneous three-phase composite consisting of mortar, aggregates and the interfacial transition zone (ITZ). By exerting a steady state flow in the concrete sample, the effective permeability is estimated using finite element method (FEM). Extensive Monte Carlo (MC) simulations for more than 1000 concrete samples are carried out. The effects of the mesostructural parameters (i.e., the shape, gradation and volume fraction of aggregates and the thickness and permeability of ITZ) on the permeability of concrete are comprehensively investigated. For a specific set of mesostructural parameters, the size of the representative volume element (RVE) for concrete permeability is suggested in terms of the expected errors by numerical and statistical analysis. It shows that computational homogenization for estimating the effective permeability of concrete in three dimensions (3D) is absolutely necessary since the two dimensional (2D) results are less representative.