Experimental Study of Crack Closure on Heterogeneous Quasi-Brittle Material

Abstract

In civil engineering, the behavior of a cracked concrete is a major challenge with regard to the management of a structure’s durability. The purpose of this experimental work is to better understand the behavior of a quasi-brittle cracked material at macro-scale, and to provide new data for numerical models. Cyclic compression/tension tests were performed on a notched concrete specimen. The effects of cracks’ closure opening were investigated by classical measurements (displacement sensors) and digital image correlation. Damage and inelastic strains were exhibited when cracks propagate during the tensile phase. When the load is reversed to induce compressive stress, the effect of damage on the concrete stiffness was progressively reduced. A relation between the inelastic strains and the damage variable emerges, and it is proved that these two variables are not thermodynamically independent. The study on the crack lips’ displacement shows that at least a part of the inelastic strain is due to the friction between the crack lips. The evolution of the damage and the dissipated energy during a loading cycle were also calculated, and results showed that the dissipated energy grows hyperbolically with the crack propagation.