Documents disponibles écrits par cet auteur

Damage of stainless steel bars due to atmospheric corrosion / A. Burkert in Materials and corrosion, Vol. 63 N° 3 (Mars 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 3 (Mars 2012) . - pp. 264–270 Titre : Damage of stainless steel bars due to atmospheric corrosion Type de document : texte imprimé Auteurs : A. Burkert, Auteur ; J. Lehmann, Auteur Année de publication : 2012 Article en page(s) : pp. 264–270 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Atmospheric  corrosion;  EPR  test;  failure;  intercrystalline  corrosion;  stainless  steel Résumé : In addition to constructional requirements in civil engineering stainless steels often have to fulfil high visual demands. Unexpected impairments of the visual appearance of stainless steels under low corrosive conditions are a widespread problem today. Frequently it is supposed that this is caused by changes in the alloy composition, worse environmental conditions or improper handling. Within a research project the systematic investigation of several cases of damaged stainless steel bars has shown that the reasons are based on well-known material defects like chemical inhomogeneities (e.g. precipitations or local carburization) or geometrical defects (e.g. undercuts, rolling defects or shell formation). Thus, the failures could be clearly identified as production failures of the respective semi-finished products. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005701/abstract [article] Damage of stainless steel bars due to atmospheric corrosion [texte imprimé] / A. Burkert, Auteur ; J. Lehmann, Auteur . - 2012 . - pp. 264–270. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 3 (Mars 2012) . - pp. 264–270 Mots-clés : Atmospheric  corrosion;  EPR  test;  failure;  intercrystalline  corrosion;  stainless  steel Résumé : In addition to constructional requirements in civil engineering stainless steels often have to fulfil high visual demands. Unexpected impairments of the visual appearance of stainless steels under low corrosive conditions are a widespread problem today. Frequently it is supposed that this is caused by changes in the alloy composition, worse environmental conditions or improper handling. Within a research project the systematic investigation of several cases of damaged stainless steel bars has shown that the reasons are based on well-known material defects like chemical inhomogeneities (e.g. precipitations or local carburization) or geometrical defects (e.g. undercuts, rolling defects or shell formation). Thus, the failures could be clearly identified as production failures of the respective semi-finished products. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005701/abstract

Electrochemical investigations on the corrosion behaviour of galvanized reinforcing steels in concrete with chromate-reduced cements / G. Ebell in Materials and corrosion, Vol. 63 N° 9 (Septembre 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 9 (Septembre 2012) . - pp. 791–802 Titre : Electrochemical investigations on the corrosion behaviour of galvanized reinforcing steels in concrete with chromate-reduced cements Type de document : texte imprimé Auteurs : G. Ebell, Auteur ; A. Burkert, Auteur ; J. Lehmann, Auteur Année de publication : 2013 Article en page(s) : pp. 791–802 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Cement;  chromate;  concrete;  electrochemical  measurements;  galvanized  steel;  polarization;  pull-out  tests;  reinforcing  steel;  zinc Résumé : The reduction of the chromate contents in cements affects the electrochemical reactions of galvanized reinforcing steels in fresh concrete. By means of electrochemical measurements and bar pull-out tests the effect of chromates on the formation of protective coatings at the zinc and the bond behaviour have been investigated using chromate-containing and chromate-reduced cements. The results have shown that the bond zone was affected as a result of chromate reduction for cement types CEM I and CEM II. The disturbance to the bond zone should be considered as long-term in relation to the pore structure which is formed. The effects on the bond are largely compensated for as the concrete ages. The results of the related bond strength with displacement paths of 0.1 and 0.5 mm, respectively, are still within the range of expected figures for non-galvanized reinforcing steel despite the structural disturbance. Under practical aspects it is not necessary that the existing structural disturbance with respect to bond strength is taken into consideration. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201106311/abstract [article] Electrochemical investigations on the corrosion behaviour of galvanized reinforcing steels in concrete with chromate-reduced cements [texte imprimé] / G. Ebell, Auteur ; A. Burkert, Auteur ; J. Lehmann, Auteur . - 2013 . - pp. 791–802. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 9 (Septembre 2012) . - pp. 791–802 Mots-clés : Cement;  chromate;  concrete;  electrochemical  measurements;  galvanized  steel;  polarization;  pull-out  tests;  reinforcing  steel;  zinc Résumé : The reduction of the chromate contents in cements affects the electrochemical reactions of galvanized reinforcing steels in fresh concrete. By means of electrochemical measurements and bar pull-out tests the effect of chromates on the formation of protective coatings at the zinc and the bond behaviour have been investigated using chromate-containing and chromate-reduced cements. The results have shown that the bond zone was affected as a result of chromate reduction for cement types CEM I and CEM II. The disturbance to the bond zone should be considered as long-term in relation to the pore structure which is formed. The effects on the bond are largely compensated for as the concrete ages. The results of the related bond strength with displacement paths of 0.1 and 0.5 mm, respectively, are still within the range of expected figures for non-galvanized reinforcing steel despite the structural disturbance. Under practical aspects it is not necessary that the existing structural disturbance with respect to bond strength is taken into consideration. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201106311/abstract