Effect of aggregate shape and volume on concrete fracture: A mesoscale modelling

Concrete has an intricate internal structure exhibiting non-linear postpeak softening and quasibrittle fracture behavior. To accurately capture its mechanical and failure behavior, it is imperative to understand the interaction between major constituting phases of concrete. In this study, the effect of aggregate shape and volume fraction on mesoscale fracture of geometrically similar beams have been investigated. A two-dimensional mesoscale model consisting of mortar, aggregate and interfacial transition zone has been modelled using cohesive elements in finite element method. The models are subjected to three-point bending and the fracture behavior is governed by damage-based constitutive laws. A rigorous fracture characterization has been conducted for different aggregate packing percentages with circular, elliptical and polyhedron geometries. The findings highlight the role of mesoscale modelling for predicting the mechanical and fracture behavior in concrete mixes.