Evaluation de la peau du béton à l'aide de la technique des ondes ultrasonores de surface
Résumé
Concrete cover degradation is induced by aggressive agents in ambiance, chemicals, moisture, or temperature variations. Due to these degradations, a thin inhomogeneous surface layer usually appears. Its porosity and its elastic modulus are different from the properties of deeper sound concrete. Therefore, the on-site nondestructive evaluation of concrete cover is important to monitor the integrity of concrete structures and prevent irreversible damage. In this paper the methodology applied is the technique, classical for geophysics, called Multichannel Analysis of Surface Waves (MASW). It is used as the NDT tool to characterize the depth and elastic modulus of concrete cover. The procedure consists in generation and reception of surface waves, using the non-contact transducers which move automatically. Then the phase velocity dispersion characteristic V(f) is extracted and inverted using the CLOUD inversion software in order to obtain the variation of shear wave velocity as a function of depth.