In Japan, many civil infrastructures such as bridges and port facilities constructed between the 1950s and the 1970s have undergone severe degradation due to corrosion. Therefore, many of these infrastructures are in a condition requiring repair or replacement. Corrosion affects the performance of a structure by weakening it leading to either gradual or abrupt failure. The severity of corrosion damage is highly dependent on the environmental conditions under which the steel is exposed. The abundance of oxygen, moisture, and chloride ions, due to salinity of seawater, as well as the physical action of the water waves, makes marine environment one of the most severe environments and a highly conducive one for corrosion to thrive. The current study investigated the corrosion characteristics of steel pipes exposed to such an environment.
For effective assessment of the remaining capacity of corroded steel structures in order to decide whether to repair, retrofit or replace a corroded member, condition assessment of the corroded surface is important. In this paper, surface characteristics of corroded steel surfaces were studied by computing descriptive statistical parameters. Steel surfaces studied were from steel pipe piles exposed in marine environment for 19.5 years. The relationship between the degree of corrosion, in terms of thickness reduction, and surface roughness characteristics was investigated. Preliminary investigation revealed that parameters related to surface heights variations have a strong correlation to corrosion degradation.