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Impedance spectroscopy: An efficient tool to determine the non-steady-state chloride diffusion coefficient in building materials / I. Sanchez in Materials and corrosion, Vol. 62 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 2 (Fevrier 2011) . - pp. 139–145 Titre : Impedance spectroscopy: An efficient tool to determine the non-steady-state chloride diffusion coefficient in building materials Type de document : texte imprimé Auteurs : I. Sanchez, Auteur ; M. P. Lopez, Auteur ; J. M. Ortega, Auteur Année de publication : 2011 Article en page(s) : pp. 139–145 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Chloride  migration  Concrete  microstructure  Diffusion  coefficient  Impedance  spectroscopy  In  situ  measurement Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : One of the most important problems of reinforced steel concrete in marine environments is the corrosion of the reinforcing bars. Most of the times, this corrosion is a consequence of the local destruction of the passive layer formed on the surface of the embedded steel, due to the arrival of chlorides present in the environment. Many efforts have been made to determine the chloride diffusion coefficient in concrete structures, both using natural diffusion methods, and accelerated migration methods. This coefficient determines the velocity of ingress of chlorides, and as a consequence the life time of the structures. In this work it is presented the possibility of using the technique of impedance spectroscopy, that is, very simple to use and requires no chemical or conductivity measurement, to determine the value of the non-steady-state diffusion coefficient. This technique, together with the equivalent circuits proposed for the interpretation of the measurements, allows the determination of the chloride saturation of a concrete or mortar sample. Pores of the material that are initially filled with water have high resistivity, and as the chlorides penetrate into the sample the value of the resistivity decreases. This diminution can be determined in situ, and permits the calculation of the diffusion coefficient saving experimental time and efforts. The results have been obtained both with concrete and mortar samples, and using different cement types. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005775/abstract [article] Impedance spectroscopy: An efficient tool to determine the non-steady-state chloride diffusion coefficient in building materials [texte imprimé] / I. Sanchez, Auteur ; M. P. Lopez, Auteur ; J. M. Ortega, Auteur . - 2011 . - pp. 139–145. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 2 (Fevrier 2011) . - pp. 139–145 Mots-clés : Chloride  migration  Concrete  microstructure  Diffusion  coefficient  Impedance  spectroscopy  In  situ  measurement Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : One of the most important problems of reinforced steel concrete in marine environments is the corrosion of the reinforcing bars. Most of the times, this corrosion is a consequence of the local destruction of the passive layer formed on the surface of the embedded steel, due to the arrival of chlorides present in the environment. Many efforts have been made to determine the chloride diffusion coefficient in concrete structures, both using natural diffusion methods, and accelerated migration methods. This coefficient determines the velocity of ingress of chlorides, and as a consequence the life time of the structures. In this work it is presented the possibility of using the technique of impedance spectroscopy, that is, very simple to use and requires no chemical or conductivity measurement, to determine the value of the non-steady-state diffusion coefficient. This technique, together with the equivalent circuits proposed for the interpretation of the measurements, allows the determination of the chloride saturation of a concrete or mortar sample. Pores of the material that are initially filled with water have high resistivity, and as the chlorides penetrate into the sample the value of the resistivity decreases. This diminution can be determined in situ, and permits the calculation of the diffusion coefficient saving experimental time and efforts. The results have been obtained both with concrete and mortar samples, and using different cement types. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005775/abstract