It is commonly accepted that there is a size effect on the nominal resistances of quasi-brittle materials such as cementitious materials. This effect must be taken into account in the design of the ultimate behavior of concrete structures in order to avoid damage and crack openings. Different theories exist in the literature to describe the size effect. Among them, we find the deterministic theory of Bazant where fracture energy is considered independent of the size and it is assumed that at peak load, the crack length is proportional to the size of the specimen.In this work, attention is paid to investigate numerically, the relationship between crack openings and length, and the size of the specimens. Various fracture parameters have also been studied by validating with the existing work for a concrete of grade M35. The present study shows the determination of fracture parameters of beams, size-ranging from 100-400 mm using ABAQUS.

Keywords: Size effect, Cohesive crack, CTOD, Quasi brittle.