Laboratory study on corrosion of steel rebars in anoxic environments - Deliverable 2.2: ConLoT project – Long-term testing of the durability of concrete at final disposal conditions

In this study, an investigate of the chloride ions causing corrosion of six different reinforcing bars by considering the effect of the chemical composition of the steel corrosion phenomenon was performed. This report includes 2 parts: (i) literature review and (ii) experimental program.

The literature review describes the fundamental aspects of the chloride induced corrosion of the reinforcement steel bars and the parameters influencing it. Also, a survey about the different electrochemical measurement of the corrosion of reinforcement steel, mainly non-destructive testing techniques, were presented in the literature review.

The experimental program presents the (i) selection of different steel rebars based on their chemical composition, (ii) the concrete materials and mix design used in the investigation and (iii) the preparation of the test reinforced concrete specimens and (iv) corrosion measurements. Six different A500HW – bars were selected by steel their chemical composition analysis and prepared for testing in eight concrete specimens each for a total of 48 separate concrete specimens. The reinforced concrete specimens and initial corrosion measurements were performed in the year 2012 and 2013. The corrosion measurements has been studied by different electrochemical testing methods during the years 2013 and 2022.

The observations during the measurement periods are not directly demonstrating that the internal composition of the steel would be relevant to the initiation period of the chloride-induced corrosion. The electrochemical testing results show high corrosion risk of the reinforcement steel bars, which was supported by the visual inspection of the specimens.