Explanation of size effect in concrete fracture using non-uniform energy distribution

A local fracture energy model originally proposed to explain the influence of fracture process zone (FPZ) on fracture energy of cementitious materials is further developed in this study. By assuming a bilinear distribution for the fracture energy distribution, the ligament-dependentfracture energy Gf is obtained. The analytical expression of Gf contains two important parameters: the intrinsic size-independent fracture energy Gf and a reference ligament size at which determines the inte section of the twolinear fracture energy functions. It is shown that the ligament-dependent Gf approaches the size-independent GF asymptotically. As a result, Gf can be determined from the ligament-dependent Gf results. It is also found that while the reference ligament size aI* is influenced by the specimen geometry, size and loading conditions, thederived fracture energy Gf is virtually constant. The present local fracture energy distribution model is also discussed and compared with the original local fracture energy model.