Repassivation of steel in carbonated concrete induced by cathodic protection |
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Authors: | L Bertolini P Pedeferri E Redaelli T Pastore |
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Abstract: | The paper discusses the peculiarities of cathodic protection applied to steel in carbonated concrete, which are strictly connected to the production of alkalinity at the steel surface. Results of a research on the application of cathodic protection to specimens with steel bars in carbonated concrete are discussed. A thin layer of concrete was realkalized within a period of 4–5 months by applying a current density of 10 mA/m2 and steel could repassivate even in the presence of small contents of chlorides. A lower current density of 5 mA/m2 could only maintain steel passive when the concrete in the vicinity of the steel had been previously realkalized through the application of a start‐up current density of 70 mA/m2 for one month. Protection mechanisms are investigated and design of cathodic protection of steel in carbonated concrete is outlined. The possibility of obtaining protection on deeper rebars is also considered. |
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Keywords: | cathodic protection carbonation chloride concrete corrosion four‐hour decay realkalization repassivation Kathodischer Korrosionsschutz Karbonatisierung Chlorid Beton Korrosion Potentialabnahme nach 4 Stunden Realkalisierung Repassivierung |
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