A Numerical Investigation on Effective Diffusion in Cement-Based Composites: The Role of Aggregate Shape

Abstract Diffusive behaviour is the fundamental mechanism of ionic-induced corrosion in cement–granular composites. Aggregate characteristics, including shape anisotropy, spatial orientation, and size distribution, significantly influence effective diffusivity. However, influences all such types aggregate irregularity have rarely been systematically quantified, most representative shapes numerical simulations are convex than realistic concave. In this study, we apply finite element method (FEM) to investigate diffusion 2D cement-based Realistic multi-scale shapes, characterised by fractal dimension ( F d ) relative roughness R r ), generated highlight morphology on The distribution evaluated disorder index. From results, samples with a larger index, indicating broader throat show smaller diffusivities. Meanwhile, causes much diffusivities, highlighting necessity concave particle simulations. Sensitivity studies more related diffusivity other single-scale classical parameters. At last, model only these two parameters proposed predict This work further improves understanding role diffusivity, towards applications two-phase Highlights grain composites using Fourier transformation. Effects characteristics investigated. key geometrical influencing