Corrosion Propagation Monitoring of Legacy Samples and Forensic Analysis on Selected Samples

Abstract As part of a recent experimental campaign several samples prepared in 1994 with various concrete compositions were terminated. These samples were exposed outdoors to seawater wet/dry cycles from 1994 till 2019, and since then to outdoor marine exposure. The remaining samples were monitored since 2021 with galvanostatic pulse measurements and more recently using a commercial device. The terminated samples showed cracks on the concrete surface, a negative rebar potential and a high corrosion rate. One or more rebars were removed from the selected samples. In some cases, the three top rebars were removed, in other cases only one rebar or two rebars were removed. The rebar surface condition upon exposure was recorded by photographing the sample, then the rebars were cleaned by sandblasting the rebars with walnut sand. The cross-section loss as a function of length was measured by using a caliper with conical tip. The pitting factor was calculated using only the sections that showed corrosion, the non-corroding sections were not included to calculate the pitting factor. The percentage mass loss (η) values were estimated by using the mass of the rebar section rebar embedded with respect to the mass a non-corroding rebar of the same length.