2. Measuring reinforcement coating thickness

Armatures are quite commonly located using devices (profometers, pachometers) based on the principle of metal detectors. These devices are sensitive to the influence exerted by a metal object on the magnetic fields it creates. But more sophisticated techniques have been the subject of research in recent years. A microwave imaging system for non-destructive testing of metal reinforcements has been designed by the LCPC (Laboratoire Central des Ponts et Chaussées) and a team from the CNRS/ESE (Centre National de la Recherche Scientifique / École Supérieure d'Électricité) [5] . This new technique uses the reflected microwave electric field to form cross-sectional images (microwave tomography) of the medium under investigation. It is thus possible to obtain images with sub-centimeter resolution, in both directions of the section...