Evaluation of cover concrete and assessment of chloride ingress by Non Destructive Testing
Résumé
During the European research program MEDACHS, four Non Destructive Testing methods (NDT) have been carried out for the study of the evolution of the physical properties of concrete samples stored in tidal zone. The main objective was the application of these NDT methods to the forecast of the maintenance actions of works according to exposure time in tidal zone. Two electromagnetic methods: Ground Penetrated Radar technique (GPR), capacitive method with an array of three different of electrodes, an electric method (resistivity measurement – see part I) and a sonic technique (sonic testing with laser interferometer) have been used. The testing methods have been developed to tend to correlate the physical properties of the concrete, like apparent complex dielectric permittivity, apparent resistivity and mechanical properties (Young modulus, Lamé coefficients), with the intrinsic ones like porosity, chloride and water content or mechanical strength. The results obtained with electric and electromagnetic methods corroborate the trend of a moisture gradient in the material. These techniques, coupled with the acoustic measurements allow the detection of local heterogeneities (empty zones, granular distributions) or anisotropies (electric, electromagnetic properties). The localization of these heterogeneities is easy with NDT without extracting many cores samples.
Domaines
Génie civil| Origine | Fichiers produits par l'(les) auteur(s) |
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