TY - JOUR A1 - Eichler, Thorsten A1 - Isecke, Bernd A1 - Bäßler, Ralph T1 - Investigations on the re-passivation of carbon steel in chloride containing concrete in consequence of cathodic polarisation JF - Materials and corrosion N2 - Although the complex changes at the steel-concrete interface due to cathodic polarisation are widely acknowledged to have a beneficial influence concerning the cathodic protection (CP) of steel in concrete, some questions concerning the repassivation of carbon steel in consequence of cathodic polarisation are still not satisfactorily clarified. In the recent literature, some indications are presented that repassivation occurs after a certain time of polarisation. Therefore, the investigations discussed in this paper aim to clarify, to what extent the re-passivation of carbon steel due to cathodic polarisation occurs, and if the ennoblement of OCP is a sufficient indication for repassivation. In a first step, the corrosion state of five nominal equal test specimens was determined by electrochemical impedance spectroscopy (EIS). After determining the initial corrosion state by evaluating the charge transfer resistance and the polarisation resistance, respectively, the specimens were polarised cathodically. Impedance data were recorded before, during and after polarisation. The impedance data were evaluated by equivalent circuit fitting with special attention to charge transfer resistances and the impact of diffusion on the corrosion and polarisation behaviour. The results indicate that the reduction of oxides and oxygen diffusion during cathodic polarisation has strong impact on the systems behaviour and that repassivation effects occur after switching off the polarisation current and during depolarisation, respectively. KW - Steel in concrete KW - Cathodic protection KW - Pitting corrosion KW - Mild steel KW - Electrochemical impedance spectroscopy KW - Chlorides KW - Corrosion KW - High alkaline environment KW - Reinforced concrete KW - Unalloyed steel KW - Passivity PY - 2009 DO - https://doi.org/10.1002/maco.200805142 SN - 0947-5117 SN - 1521-4176 VL - 60 IS - 2 SP - 119 EP - 129 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-18808 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -