Numerical insights into the effect of ITZ and aggregate strength on concrete properties

Mechanical properties of concrete are highly dependent on its components. Consequently, a comprehensive understanding of the effects of aggregate and interfacial transition zone on concrete properties is important to applications. In this paper, a mesoscale investigation on the effects of coarse aggregate and interfacial transition zone strength on mechanical and fracture behaviours of concrete is investigated using discrete element modelling. The results show that the elastic modulus of concrete is insensitive to the strength of ITZ and aggregate, whereas the compressive strength and strain-to-damage highly depend on these two factors. An increase in ITZ/aggregate strength leads to a decrease of cracks in ITZ/aggregates and little change of cracks in mortar. Aggregate size, under certain conditions, can alter the crack growth process and result in distinct crack patterns.