Mesoscale Modelling of Concrete Materials under Complex Loadings

Abstract

Concrete is a widely used construction material. In marine environments, its durability and mechanical performance are critical, especially regarding chloride-induced corrosion and structural behaviour under complex stresses. As concrete is a complex composite exhibiting heterogeneity across length scales from the nano- to the macroscale, this work particularly focuses on the mesoscale, as this scale allows the assessment of macroscopic performance while supporting it with microscopic evidence. At the mesoscale, the concrete can be treated as a three-phase composite of cement paste, aggregates, and the interfacial transition zone (ITZ). Aggregates, as the strongest and most impermeable phase, significantly influence performance. However, many studies simplify aggregate shapes, and controlling shape irregularity experimentally is difficult, leaving the effects of realistic aggregate morphology on concrete diffusivity and fracture insufficiently understood. To bridge this gap, this research conducts mesoscale modelling of concrete with realistic aggregate shape to provide new macro- and microscopic insights into the influence of aggregate shape on various single-physical behaviours of concrete. These include ionic diffusion related to chloride-induced corrosion, as well as concrete fracture under triaxial and dynamic loading conditions that represent complex stress environments. The findings provide a new understanding of concrete transport and mechanical behaviours, highlighting the role of aggregate shape irregularity in the diffusivity and strength of concrete.