Post-failure behavior of concrete materials in compression

Abstract

Since macroscopic observations yield no significant information regarding the post-failure softening behavior of concrete, a microscopic approach is therefore taken in the present study. Microscopic experimental observations show that post-failure behavior is closely associated with the development of mortar cracks. A micromechanical study suggests that the presence of transverse tension in the mortar region is crucial for the unbounded growth of a mortar crack leading to tensile failure under compressive loading. Furthermore, the stress analysis of concretelike composites reveals the considerable dependence of the stress state in the mortar region on the relative locations of aggregates in the neighborhood. The conclusion drawn from these studies is that the deformation in the post-failure regime is likely to be nonhomogeneous. This conclusion casts doubt about the legitimacy of an analytical effort to reproduce post-failure macroscopic stress-strain curves and seems to give a rational reason why the description of softening behavior in terms of macroscopic stress and strain becomes inappropriate after failure.