Réflectométrie fréquentielle (FDR) appliquée à l'évaluation non destructive des conduits de précontrainte extérieure, perspective pour la mesure de la teneur en eau du béton

This paper presents an electromagnetic method of diagnosis based on frequency domain reflectometry (FDR) associated with an inversion algorithm developed by INRIA, ISTLTM (Inverse Scattering for Transmission Lines). ISTLTM allows estimating the spatial profile of the electrical impedance of the line from the FDR measurements. Experimental results on two mockups of external post-tensioned ducts with filling defects show the feasibility of the method. We will try to show the similarities between auscultation external post-tensioned ducts and measurement of water content by TDR probes (Time Domain Reflectometry).