環境促進実験を用いた鋼橋塗装系の腐食劣化評価

This study examined to evaluate the corrosion durability of painting systems for steel bridges. Accelerated corrosion cyclic tests conforming to JIS K5621 were carried out on three types of the painting systems, i.e. A-painting system for mild condition, C-painting system for severe corrosion condition, and a newly developed heavy duty I-painting system. Cross-scribed lines reaching the steel substrate were mechanically made in the painted surface, and uncoated region of 20 × 70 mm was also introduced in the lower part of the test specimens. The three types of painted specimens were exposed into the S6-cycle corrosion environments during 100, 200 and 400 days. Blistering area, tensile adhesion, glossiness, appearance and surface geometry of the paintings were measured at the exposure times of 0, 100, 200, 300, and 400 days. After removing painting films and corrosion productions by chemical treatment, the thickness loss of steel substrate was also measured. From the test results, the corrosion degradation degree of the three types of bridge paintings systems was quantiatively evaluated.