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Imaging concrete structures using air-coupled impact-echo / Jinying Zhu in Journal of engineering mechanics, Vol. 133 N°6 (Juin 2007) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 133 N°6 (Juin 2007) . - pp.628–640. Titre : Imaging concrete structures using air-coupled impact-echo Type de document : texte imprimé Auteurs : Jinying Zhu, Auteur ; John S. Popovics, Auteur Année de publication : 2007 Article en page(s) : pp.628–640. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Concrete  structures  Ducts  Imaging  techniques  Nondestructive  tests  Sensors Résumé : In this paper, air-coupled impact-echo is successfully applied for nondestructive evaluation of concrete. The air-coupled sensor is a small ( [Math Processing Error] diameter) measurement microphone located several centimeters above the top surface of the concrete being evaluated. Unwanted ambient acoustic noise is attenuated by a specially designed sound insulation enclosure. Test results show that air-coupled sensors are effective for impact-echo when appropriate impactors are used. Impact-echo data obtained by air-coupled sensors are equivalent to those obtained by conventional contact sensors. Test results from concrete slabs containing artificial delaminations and voids are reported, where an air-coupled impact-echo scan is conducted over the entire slab area. Defects are located in the generated two-dimensional contour image. The areal size of defects are accurately determined when the measurement point spacing in the scan is smaller than half of the expected defect size. Test results from air-coupled impact-echo scans carried out over internal metal and plastic ducts within another concrete slab are also reported. The goal of the experiment is to investigate the grouting condition inside the ducts. Impact-echo line scan images differentiate poorly grouted sections from the well-grouted sections within the metal duct. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A6%2862 [...] [article] Imaging concrete structures using air-coupled impact-echo [texte imprimé] / Jinying Zhu, Auteur ; John S. Popovics, Auteur . - 2007 . - pp.628–640. Applied mechanics Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 133 N°6 (Juin 2007) . - pp.628–640. Mots-clés : Concrete  structures  Ducts  Imaging  techniques  Nondestructive  tests  Sensors Résumé : In this paper, air-coupled impact-echo is successfully applied for nondestructive evaluation of concrete. The air-coupled sensor is a small ( [Math Processing Error] diameter) measurement microphone located several centimeters above the top surface of the concrete being evaluated. Unwanted ambient acoustic noise is attenuated by a specially designed sound insulation enclosure. Test results show that air-coupled sensors are effective for impact-echo when appropriate impactors are used. Impact-echo data obtained by air-coupled sensors are equivalent to those obtained by conventional contact sensors. Test results from concrete slabs containing artificial delaminations and voids are reported, where an air-coupled impact-echo scan is conducted over the entire slab area. Defects are located in the generated two-dimensional contour image. The areal size of defects are accurately determined when the measurement point spacing in the scan is smaller than half of the expected defect size. Test results from air-coupled impact-echo scans carried out over internal metal and plastic ducts within another concrete slab are also reported. The goal of the experiment is to investigate the grouting condition inside the ducts. Impact-echo line scan images differentiate poorly grouted sections from the well-grouted sections within the metal duct. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A6%2862 [...]