Evaluating concrete surfaces using an image analysis process

This study concerns the assessment of non-coated concrete surfaces in civil engineering structures and buildings. Imaging is used as an objective tool for evaluation of the surfaces. Because images of surfaces taken under different conditions of illumination are difficult to compare, this paper presents a method suggested by the building firm GTM Construction and the laboratory LMDC for obtaining images of luminance L∗ simulated for one standard illuminant (D65). Concrete surfaces can be qualified with respect to uniformity of tint and distribution of surface bubbles. The process described is based on image analysis. Not only can the results be compared with current standards, but the method also gives access to additional, accurate information such as the distribution of defects and the size of surface bubbles. This method is already applied on building sites for experts' assessments and in the laboratory for the study of the parameters influencing surface quality.