Compression failure of quasibrittle materials and size effect

The paper presents a model for size effect in the failure of columns or other compression made members made of quasibrittle materials such as concretes, rocks, or composites. The size effect is explained by energy release due to transverse propagation of a band of axial splitting cracks. The microslabs of the material between the splitting cracks are considered to buckle and undergo post-critical deflections. The failure condition is based on the equality of the energy released from the uncracked elastic member and the energy consumed by the axial splitting cracks in the band. The analysis leads to a closed-form expression relating the nominal strength of the structure and the structures characteristic size. The resulting formulation is compared to the test results on model reinforced concrete columns reported previously by Bazant and Kwon (1994). Satisfactory match of the test data is achieved.