Evaluation of Galvanic Coupling of Lean Duplex Stainless Steel and Carbon Steel in Simulated Pore Solution for Concrete Structures in Marine Environment

摘要

Duplex stainless steels are used in concrete structures installed under highly aggressive conditions, such as marine atmosphere or areas with intense use of deicing salt. This type of bar is used when a long service life is required (over 100 years) or when there are maintenance restrictions such as inaccessibility or very high maintenance costs and disturbances to the population. Due to the high initial cost, the use of duplex stainless steel bars are restricted to the outside layer of a concrete structure which is directly subjected to a chloride contamination, whereas at the inside areas or in areas protected from a chloride contamination, carbon steel bars are used electrically connected to the stainless steel bars. However, the galvanic corrosion of the stainless steel/carbon steel couple is a concern because different metals are kept in contact with each other in the structure. This work aims at studying the behavior of UNS* S32304 stainless steel bars in electric contact with bare steel bars. Corrosion tests were conducted with the bars immersed in a simulated pore solution with and without contamination by chloride ions. Tests using 304 SS were conducted as a reference.