Atmospheric corrosion behavior of carbon steel and galvanized steel in Southwest China

This study investigated the atmospheric corrosion behavior of carbon steel and galvanized steel framing samples at residential buildings in Southwest China over a three-year period of exposure. The study was begun in 2010 when four monitoring sites were established and test samples installed in a case study area at Dujiangyan City, Sichuan Province. Particularly, corrosion behavior, including corrosion morphology, corrosion rate and the composition of corrosion products of the selected steel samples, were analyzed under local atmospheric conditions. The results showed that the corrosion rate of the steel varied considerably at the four different monitoring sites due to significant temperature and moisture differences at the locations. By increasing the testing cycles, the corrosion rates of the steel tended to decrease, and the galvanized coating of the steel surface could effectively protect the base metal from corrosion in the atmospheric environment. The main factors that might affect corrosion behavior seem to be relative humidity, wet condition and the fluctuation of relative humidity. These findings could help municipal authorities and local communities make sound management strategies in the future regarding the treatment and re-use of discarded construction materials.