STUDY OF CORROSION LEVEL AND COMPOSITION OF ACCUMULATING SALT ON WEATHERING STEEL BRIDGES

Abstract

To estimate corrosion environment for weathering steel bridge, we investigated chemistry of salt and corrosion level on girders of the bridges in Shimane. Quantities of Na⁺ and Cl^- on girders are positively correlated with rust thickness and corrosion level, indicating that these quantities are proxies for corrosion environment. Girders with Na⁺ and Cl^- volumes higher than 5 mg/m²/y show thicker rust than 400 μm and worse corrosion feature, suggesting weathering steel should not be used under such environment. Relative to web, lower flange is enriched in Na⁺ and Cl^-, and shows worse corrosion feature. Accumulating salt on web potentially migrates to lower flange due to dew, and corrosion on flange probably advances.