Diagnosis of Reinforced Structures: An Active Microwave Imaging System

Pichot, Ch.; Trouillet, Pierre-Yves

doi:10.1007/978-94-009-2153-5_15

Cited by 7 publications

(2 citation statements)

References 2 publications

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“…With respect to the corrosion of rebars, that is mainly due to carbonation and chloride ions present in the concrete constituents or introduced during the service life (see Shamsad (2003) for an overview about corrosion in concrete rebars), several sensing methods have been developed, among them we mention techniques based on static magnetic field measurements, such as residual magnetic flux density and magnetic flux leakage (Makar and Desnoyers, 2001), impedance probes (Miller et al, 2003;Chady et al, 2004;Rubinacci et al, 2005), microwave tomography (Zoughi et al, 1991;Pichot and Trouillet, 1990) and polarization resistance-based techniques (Law et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic inspection of concrete rebars

Magistris

Morozov

Rubinacci

et al. 2007

COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering

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Purpose -The paper aims to apply an innovative inversion method to the problem of imaging (location, direction and size) of concrete rebars by means of eddy current measurements. Design/methodology/approach -An accurate numerical model of the probe-rebar interaction, including eddy currents and skin effect, is considered. The inverse problem is approached with a very efficient inversion procedure previously introduced in a different context. Findings -A critical analysis of the issues to be considered for the quantitative imaging of rebars is given, and the possibility of relevant simplifications in the numerical model outlined, allowing the development of an accurate and computationally efficient method. Originality/value -The proposed formulation is applied for the first time to the problem of rebars imaging. Experimental tests have been carried out to validate the numerical model and its underlying hypothesis.

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Section: Introductionmentioning

confidence: 99%

Electromagnetic inspection of concrete rebars

Magistris

Morozov

Rubinacci

et al. 2007

COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering

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“…L'application de la technique du radar au matCriau bCton reste difficile en raison, d'une part, de la sensibilitC de la constante diClectrique B I'humiditC et, d'autre part, de la forte attinuation des ondes Clectromagnttiques dans le bCton, laquelle limite leur propagation B de courtes distances (Pichot et Trouillet 1990 (Giafferi 1992). RCcemment, la tomographie sonique a CtC appliquCe au contr6le de l'injection (Gautier 1991 Les premikres Ctudes concernant le suivi acoustique d'une injection datent d'une dizaine d7annCes (Batchelor 1983;Pearson 1981).…”

Section: Introductionunclassified

Suivi de l'injection au moyen de l'émission acoustique

Rhazi¹,

Ballivy²

1993

Can. Geotech. J.

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R e p le 15 mars 1993 Accept6 le 21 juin 1993 L'injection de coulis dans des microfissures de barrages de bCton en service est trbs dClicate en raison des fortes pressions que l'on doit appliquer compte tenu de la faible ouverture des fissures. Ces conditions d'injection peuvent entrainer la propagation des fissures et contribuer B la dkstabilisation du massif. Les possibilitCs de la technique du suivi en temps reel d'injections au moyen de 1'Cmission acoustique ont Ct C examinies. Des essais d'injection d'eau ont CtC men& sur des dalles fissurCes de biton de grandes dimensions (2,64 m sur 1,42 m; Cpaisseur, 0,40 m) et instrumentees de capteurs de pression, de charge et de dCplacement. Selon une Ctude comparative de deux types de capteurs d7Cmissions acoustiques, ceux travaillant en basse frCquence paraissent plus appropriCs pour ce type d'application. D'autre part, les signaux acoustiques dCtectCs ne sont pas dus B un Ccoulement 21 pression constante, mais aux accClCrations et dCcClCrations du produit inject6 et aux mCcanismes rCsultant des variations de pression et de dCbit du fluide (ouverture et fermeture de la fissure). Ces observations confirment donc 17intCr&t que prCsente 1'Cmission acoustique pour le contrdle des injections et, particulibrement, pour la dktermination des processus d'Ccoulement du coulis.Mots clCs : bCton, fissure, injection, essai d'eau, pression, emission acoustique.The injection of grout in the microfissures of concrete dams in operation is very tricky because of the high pressures required to penetrate the slightly opened fissures. These conditions of grouting may result in the propagation of the fissures and contribute to the loss of stability of the mass. The technique using acoustical emission to follow the injection in real time has been evaluated. Water injection tests have been carried out on large dimensions (2.64 m X 1.42 m X 0.40 m) fissured concrete slabs instrumented with pressure, load, and displacement transducers. According to a study comparing two types of acoustical emission transducers, the low-frequency transducers would be more appropriate for this type of application. Moreover, the detected acoustical signals are not due to a constant pressure flow, but to the accelerations and decelerations of the grout, and to the mechanisms resulting from the variations of pressure and flow of the fluid (opening and closure of the fissure). Thus these observations confirm that the acoustical emission may be an interesting means to control the injections and, in particular, to determine the process of grout flow.

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Microwave tomography: From theory to practical imaging systems

Bolomey

Pichot

1990

Int J Imaging Syst Tech

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This paper deals with numerical processing techniques and practical applications of active microwave imaging. Different wavefront processings are presented, from an immediate use of measured projections to more complex procedures. Both spectral approaches to diffraction tomography and spatial iterative methods for generalized imaging are considered using multi-incidence or multifrequency techniques for 3D and/or 2D objects. The technology of the so-called microwave camera is presented for the fast recording of the scattered field with arrays of probes involving one-or two-dimensional sensors at a single frequency or in a broad-frequency band. Three different systems are depicted: a single-frequency linear sensor devoted to industrial applications (on-line transverse control of conveyed products), a single-frequency planar microwave camera for biomedical applications and research, and a broad-frequency linear microwave camera for civil engineering applications (detection of the rebars in reinforced concrete strctures). Microwave images obtained experimentally with the three systems are presented on configurations of practical interest for each field of application.

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Diagnosis of Reinforced Structures: An Active Microwave Imaging System

Cited by 7 publications

References 2 publications

Electromagnetic inspection of concrete rebars

Electromagnetic inspection of concrete rebars

Suivi de l'injection au moyen de l'émission acoustique

Microwave tomography: From theory to practical imaging systems

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