The factors for the deterioration of renewed coating systems on the steel members

In Japan, the rate of corrosion damage of steel members is almost half of the most serious causes of the renewals of the aged steel bridges. As one of the countermeasures of corrosion damages, the painting is used. The coating systems will deteriorate due to ultraviolet and so on in surroundings. After the occurrence of the deterioration, the renewal of the paint will be carried out. In this paper, the authors carried out the environmental acceleration test with the specimens coated with the coating system for the renewal to confirm the durability of the renewed coating systems. The measurement methods of the deterioration rate of the coatings are the visual inspection and the coating impedance measurement technique. According to the measured results, we estimate the influences of the type of the coating, the method of surface preparation and the amount of accumulated salt on the surface of steel.