Surface analysis of mineral substrates for repair works: roughness evaluation by profilometry and surfometry analysis

Existing concrete surfaces need to be roughened to a profile necessary to achieve mechanical interlock with repair material. Surface mechanical morphometry is based on the measurement of surface profile – profilometry – which can be extended to 3D representation with surfometry by means of a stylus registering the profile. Profilometry and surfometry analysis enables the quantification of the profile by means of statistical and amplitude parameters calculated from the total profile of the surface (the waviness (lower frequencies) and roughness (higher frequencies) profiles). These parameters have been used to compare sandblasted and polished concrete surfaces. Arithmetic mean of the profile and flatness coefficient are particularly discriminant. Bearing ratio and Abbott's curve observations are also useful for clear and simple characterisation of surface profiles. Moreover, this investigation led to the calculation of the specific length of the profile and the Wenzel's coefficient.