Major Research Development of the performance evaluation method in protective coating for marine structures

Generally, two types of corrosion-prevention treatment are applied to steel marine structures simultaneously, namely cathodic protection and protective coating, to ensure their long-term durability. Regarding protective coating techniques, their deterioration characteristics (usable lifespan, etc.) are being elucidated through exposure tests, etc. However, while it is essential to review the anticipated performance of each protective coating technique in the design phase, there is no established method to evaluate its current corrosion-prevention capability or predict its future state for the maintenance and management phase. To address this, we have been continuously conducting exposure tests at the pier of our Hazaki Oceanographical Research Station and other locations to track the temporal changes in the condition of the corrosion-preventing techniques applied to their steel piles to evaluate the durability of the protective coating materials in the marine environment. In addition, we reviewed the results of surveys conducted on various port structures, etc. that had been jointly used for extended periods (over 20 years), analyzed some of the samples taken, and evaluated the durability-enhancing ability of each of the corrosion-prevention techniques that were applied. Furthermore, we organized the results of exposure tests conducted on petrolatum coating techniques to elucidate the related deterioration mechanism and establish a method of evaluating the performance of petrolatum-based coating materials. In addition, we studied the results of previous surveys conducted on actual structures (i.e., pier superstructures at Yokohama Port) and used the data to evaluate the performance of the concrete surface coating materials that were applied to those structures.