CONTINUUM FRACTURE IN CONCRETE NONLINEARITY UNDER TRIAXIAL CONFINEMENT

Abstract

Under triaxial stresses, the continuum fracture defined as the damaged elasticity of concrete was experimentally extracted. The volumetric elasticity was found not to be mechanically damaged even though the concrete subjected to lower confinement comes up to the higher nonlimearity in appearance. On the contrary, it was verified that the elasticity of concrete in shear is seriously deteriorated according to the internal shear stress intensityy expressed by the elastic strains. The concept of the internal stress, which is directly proportional to the elasicity, was adopted for evaluation of the stress intensity applied to non-damaged volume which retains the capacity to absorb the elastic strain energy. The fracture parameter, which indicates the loss of elastic strain energy in the mode of shear, was formulated in terms of the hysteresis of the internal hydrostatic stress to represent non-localized defects in space.