Atmospheric Corrosion of Steel Infrastructure in Canada under Climate Change

Protection against atmospheric corrosion of steel infrastructure and its components requires assessment and prediction of corrosion rates using quantitative and reliable modelling of the environmental parameters that impact the corrosion process. This has become even more critical in the context of climate change. This study demonstrates the feasibility of using ISO Dose-response Functions (DRFs) to classify atmospheric corrosivity in Canada to improve the current qualitative approach to the corrosion design of carbon steel infrastructure, especially bridges. The DRF predictions for first-year corrosion rates were first confirmed using a set of historical field data collected from different locations across Canada. Further examination has revealed a dramatic change in atmospheric corrosivity at many locations in Canada since the last systematic effort in field data collection in the 1950-60s. it is believed that this was caused by significant drop in in sulfur dioxide levels in the atmosphere. A projection of future corrosivity in various Canadian cities with differing climates was also presented by considering the projected impacts of climate change on the temperature and relative humidity. This study has shown a promising precursor for the development of a corrosivity map in Canada to better guide the corrosion design and protection of steel infrastructure. Furthermore, this study has demonstrated an acute need to understand the current chloride deposition conditions of steel bridges, including the increased local exposure of roadways to corrosivity by the use of de-icing salts.