Elution of Cr6+ from corrosion product on weathering steel bridges

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K06481
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Structural engineering/Earthquake engineering/Maintenance management engineering
• Research Institution: Matsue National College of Technology
• Principal Investigator: Takebe Masamichi 松江工業高等専門学校, 環境・建設工学科, 教授 (40390489)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 耐候性鋼橋梁 / 維持管理 / 六価クロム

Outline of Final Research Achievements

Cr6+ is edited from corrosion product on weathering steel bridges with surface treatment agent. On the basis of analysis of exposure test for test pieces, deterioration of surface treatment agent and corrosion of weathering steels are probably related to the elution of Cr6+. The elution of Cr6+ is detected from corrosion product of the bridges, in the case that shaking solution of the corrosion product and deionized water shows high pH. The corrosion product showing the high pH contains Na+ and inorganic carbon, which are composed of sodium hydrogen carbonate.

Free Research Field

土木工学，地球化学

Academic Significance and Societal Importance of the Research Achievements

厚生労働省から，構造物補修における鉛やクロムを含む塗料の剥離や掻き落し作業に関わる労働者の健康障害防止に関する通達が出されている．しかし，耐候性鋼橋梁の補修時の作業者の健康障害や環境負荷について不明であるため，対処方針も明確でない．
本研究で，表面処理皮膜を含む耐候性鋼橋梁の腐食生成物からCr(VI)が溶出すること，その溶出は腐食状況に関連することが明らかとなった．この結果を補修時の予備調査に活かし，部位ごとに細やかに対処方針を選定することで，補修作業者の健康障害防止や環境負荷の低減，加えて，補修コストの最適化が可能になる．以上の点で，本研究の成果は環境配慮型社会の構築に貢献できると言える．