Effect of the presence and size of a real macro-crack on diffuse ultrasound in concrete

In civil engineering structures, the first layer of concrete plays a role in terms of water-tightness, and contributes to the protection of metal frames from corrosion by external chemical agents (water, CO2, chlorine etc.). In concrete, a crack is comprised of an external part with a surface opening, and a completely or partially closed part below the surface. The aim of this paper is to identify the contribution of a real macro-crack on the diffuse ultrasound parameters. The methods ability to characterize the open part of the crack is confirmed. The results reveal the influence of the closed part of the crack, with regions in partial contacts, on the diffusion parameters.