Multiscale modelling of ionic diffusivity in unsaturated concrete accounting for its hierarchical microstructure

This study presents an integrated multiscale framework for modelling ionic diffusivity in unsaturated concrete accounting its microstructural features and 3D moisture distribution. The hierarchical microstructure of at from nano- to meso-scale is mimicked, based on which the fluid-solid interaction distribution pore network with various saturation levels are simulated using a lattice Boltzmann multiphase model. A Boltzmann-finite difference model diffusion developed mimic predict concrete. Results indicate that highly depends content distribution, structure, aggregate content. As water level drops around 90%, interfacial transition zone starts retard diffusion. Voids have great contribution but less effect diffusivity. simulation results each scale agree well experimental data.