2017 Volume 66 Issue 12 Pages 395-400
This study analyzed weathering steel test pieces that were exposed around the bridge in mountainous area for 27 years. In account of Ion transfer resistance method, corrosion level of the test pieces without supplementary rust controlling treatment coating is I-5 or I-4. In spite of the long exposure duration, their rust consists mostly of amorphous substance and a little α-FeOOH, which is considered to be main composition of protective rust of weathering steels. Weathering steel test pieces with supplementary rust controlling treatment coating retains coating with fading color among rust spots. In only case of top surface of the test piece horizontally exposed between girders of the bridge shows transformation of the treatment coating to rust. The test pieces with and without coating show little depletion of the thickness during 27 years, suggesting that environment of this area is mild in terms of corrosion and is suitable for weathering steel bridges, nevertheless inadequate formation of α-FeOOH.