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

Abstract

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.

Near-to-surface properties affecting bond strength in concrete repair

“…Calculation of statistical and amplitude distribution parameters of the profile allows a quantitative and objective evaluation of the surface geometry [22]. Profile can be obtained by means of profilometers (mechanical and laser) or digitalization of the cross-section image [6,16].…”

Surfology: concrete surface evaluation prior to repair

“…The determination of surface parameters (Table 1) is realised on the basis of the mean line as a reference line (Courard [4]). Interesting information from surface analysis is the bearing ratio (Courard and Nélis [3]) and the Abbott's curve (Fig. 3).…”

“…The technique has been already described in details (Courard and Nélis [3]) and is only here rapidly remembered. A stylus is walked along the surface to be analysed and the profile is continuously registered (Fig.…”

“…4). The total registered profile is filtered in high and low frequencies in order to separate roughness and waviness, respectively (Courard and Nélis [3]). Filtering will reduce to 50% of the initial amplitude of a wave when its wavelength corresponds to the filter characteristic.…”

“…However, the effects of surface preparation technique is never clearly described or quantified: it is consequently difficult to point out the real influence of roughness on adhesion results, as this is disturbed by other effect like microcracking or bond coating (Bissonnette et al [5]). A first step was made by using mechanical profilometry to differentiate polished and sandblasted concrete surfaces (Courard et al [2], Courard and Nélis [3] and Courard [4]). This technique is very accurate for investigations in laboratory, on a limited surface area.…”