Correlation between concrete-to-concrete bond strength and the roughness of the substrate surface

Previous studies proved that the bond strength between two concrete layers is highly influenced by the roughness of the substrate surface. In this paper, the authors describe a subsequent study, conducted to investigate the possibility of quantifying the roughness of the substrate surface and correlate this with the corresponding interface bond strength. Specimens with the substrate surface prepared with different roughening techniques were considered. The roughness profile of the substrate surface was obtained with digital image processing. Several roughness parameters were assessed based on this profile and were correlated with the corresponding bond strength, both in shear and in tension, measured with slant shear and pull-off tests, respectively.