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Early stage beneficial effects of cathodic protection in concrete structures / R. B. Polder in Materials and corrosion, Vol. 62 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 2 (Fevrier 2011) . - pp. 105–110 Titre : Early stage beneficial effects of cathodic protection in concrete structures Type de document : texte imprimé Auteurs : R. B. Polder, Auteur ; W. H. A. Peelen, Auteur ; B. Th. J. Stoop, Auteur Année de publication : 2011 Article en page(s) : pp. 105–110 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Cathodic  protection  Concrete  Numerical  modelling  Reinforcement  corrosion Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Over the last 25 years, cathodic protection (CP) of reinforced concrete structures suffering from chloride induced reinforcement corrosion has shown to be successful and durable. CP current causes steel polarisation, electrochemical reactions and ion transport in the concrete. CP systems are designed based on experience, which results in conservative designs and their performance is a matter of wait-and-see. CP systems can be designed for critical aspects and made more economical using numerical models for current and polarisation distribution. Previously, principles of numerical calculations for design of CP systems were reported. The results were satisfactory, except in terms of current density for active corroding systems. This was suggested to be due to neglecting beneficial effects of CP current flow. One of the beneficial effects is pH increase at the steel surface due to oxygen reduction. As the pH increases, the corrosion rate decreases and the current demand decreases. A simple model was set up for this transient process, suggesting that such effects should occur on the time scale of hours to days. This model was validated from start up data of a CP field trial system on part of a bridge. Field results confirmed the modelling proposed here. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005803/abstract [article] Early stage beneficial effects of cathodic protection in concrete structures [texte imprimé] / R. B. Polder, Auteur ; W. H. A. Peelen, Auteur ; B. Th. J. Stoop, Auteur . - 2011 . - pp. 105–110. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 2 (Fevrier 2011) . - pp. 105–110 Mots-clés : Cathodic  protection  Concrete  Numerical  modelling  Reinforcement  corrosion Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Over the last 25 years, cathodic protection (CP) of reinforced concrete structures suffering from chloride induced reinforcement corrosion has shown to be successful and durable. CP current causes steel polarisation, electrochemical reactions and ion transport in the concrete. CP systems are designed based on experience, which results in conservative designs and their performance is a matter of wait-and-see. CP systems can be designed for critical aspects and made more economical using numerical models for current and polarisation distribution. Previously, principles of numerical calculations for design of CP systems were reported. The results were satisfactory, except in terms of current density for active corroding systems. This was suggested to be due to neglecting beneficial effects of CP current flow. One of the beneficial effects is pH increase at the steel surface due to oxygen reduction. As the pH increases, the corrosion rate decreases and the current demand decreases. A simple model was set up for this transient process, suggesting that such effects should occur on the time scale of hours to days. This model was validated from start up data of a CP field trial system on part of a bridge. Field results confirmed the modelling proposed here. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005803/abstract