Characteristics of the non-uniform corrosion of the steel bars extracted from the marine transportation infrastructures

Abstract

This paper investigates the spatial morphological characteristics of non-uniform corrosion of reinforced concrete in coastal areas. A series of naturally corroded reinforced concrete specimens were retrieved from marine transportation infrastructure. Non-destructive tests were conducted by X-ray computed tomography (CT). The morphological propagations of the corrosion pits were explored, and the spatial distribution of non-uniform corrosion of the steel bars was analyzed in both longitudinal and circumferential directions. The results show that the non-uniformity of corrosion is related to both the corrosion degree and the morphology of corrosion pits. When the morphology of corrosion pits is similar, non-uniformity decreases exponentially with the corrosion degree of the steel bars. The morphologies of corrosion pits can be divided into two main categories: surficial corrosion pits and deep corrosion pits. The morphologies are related to the non-uniformity of the concrete surrounding the steel bar. When the corrosion degrees are similar, deep corrosion pits are more significant than surficial corrosion pits for the non-uniformity of the corrosion. The eccentricity was adopted to quantify the corrosion non-uniformity of bars with high corrosion degrees. These results provide a new perspective for evaluation on the non-uniform corrosion of steel bar in the marine transportation infrastructures.