Observation of Rebar Corrosion in a 48-Year-Old RC Building under Airborne Salt Environment

Abstract

Surface observation and component analysis were conducted on rebar obtained from a 48-year-old reinforced concrete building under an environment with airborne salt in order to estimate the cause of their deterioration. Measurements included surface observation by microscope and SEM, as well as component analysis by EDS, XRD/XRF, and EPMA. Although the details of the building were purposefully concealed at the time of testing during surface observation and analysis of the specimens, a comprehensive examination of the results of each test made it possible to infer that the corrosion of rebar may have progressed due to airborne salt and carbonation, rather than internal chloride. Furthermore, although this was limited to a single case, the authors were able to show the shape and component distribution of corrosion product under an actual exposure environment.