Combination of mechanical and optical profilometry techniques for concrete surface roughness characterisation

Achieving durable bond between new and old concrete still represents a challenge in concrete repair technology. It has been the subject of a number of investigations, but in most cases, only adhesion strength was addressed. To better understand bond mechanisms, in particular those related to surface roughness, two complementary surface characterisation techniques were implemented, providing a multiscale roughness characterisation by means of specific filtering calculations: mechanical profilometry for low-scale roughness and optical profilometry for the upscale roughness. Using these complementary approaches, different types of concrete surface preparation were characterised. The resulting description highlights the complexity of concrete surface topography. Moreover, it shows that the type of surface preparation essentially affects the meso- and macro-roughness levels, micro-roughness being practically insensitive. Such results will be useful for better understanding the interlocking potential and bond performance of concrete repairs.