Two different techniques for the evaluation of concrete surface roughness

The study of adhesion of repair materials on concrete structures implies a good knowledge of the influence of concrete surface treatment. The effects of surface preparation technique is rarely clearly described and parameterised: it is consequently difficult to point out the real influence of roughness on adhesion results. A first step was made by using mechanical profilometry to differentiate concrete surfaces prepared by shot blasting, sand blasting and hand or mechanical milling. This technique is very accurate for investigations in laboratory, on a limited surface area. If Quality Control is requested or if it is impossible to core samples from the site, other procedures should be followed. That the reason why opto-morphometry analysis has been developed, in order to analyse larger surfaces. The comparison of the two techniques shows clearly the advan-tages of each one and the precision that can be achieved.