The effects of ocean salinity variance due to climate change on Australian seaport infrastructure

As the effects of climatic change become more evident and extreme, there is significant pressure being mounted onto port authorities and infrastructure stakeholders to ensure that their assets are resilient to the effects of a more aggressive and corrosive climate. Typically, the reinforcing steel within concrete which provides its flexural strength is protected from corrosion by both the alkalinity of the cement and the distance of cover from the chloride laden environment. However, studies are suggesting that as the hydrological cycle around the equator begins to accelerate, the salinity of the oceans at these lower latitudes (namely from 25°S to 25°N) will increase. As demonstrated through Fick's 2^nd Law of diffusion, there will then be an effect on the build-up of surface chlorides and thus, chloride ingress through the cement matrix to initiate corrosion. Through an extensive literature review of climatic forecasts, and both laboratory and infield trials, this paper will numerically demonstrate the relationship between salinity concentration and surface chloride levels at varying temperatures. The results illustrate a strong positive relationship between the two parameters suggesting faster corrosion initiation, and more frequent operational downtime for stakeholders into the future. To fill this gap in knowledge, the surface chloride equations presented should be considered when design, maintenance, and retrofitting options are being considered for stakeholders within the affected locations.