Abstract
In paint-coated steel structures, the corrosion tends to initiate not only from individual coating defects but also from a plurality of adjacent coating defects; it should be interference in growth process of the corrosion. However, the influence of size and proximity of the coating defect on corrosion behavior is ambiguous and unclear. In this research, combined cyclic corrosion tests were conducted over a prolonged period using paint-coated steel plates with single and two adjacent circular defects. The test results indicate that the mean and maximum corrosion depths increased with increasing diameter of the single defect of the coated steel plate. The corrosion growth rate for specimens with two adjacent circular defects is greater than that with single defect. Furthermore, in order to clarify the electrochemical mechanism between two adjacent circular defects, time-dependent corrosion current was measured using a model specimen with their defects.
