Elucidation of Corrosion Mechanism of Steel Rebar in Concrete Using Rapid Straining Electrode Test and Development of a New Accelerated Corrosion Test

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K14711
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Civil engineering materials/Construction/Construction management
• Research Institution: National Institute for Materials Science
• Principal Investigator: Doi Kotaro 国立研究開発法人物質・材料研究機構, 構造材料研究拠点, 独立研究者 (80772889)
• Project Period (FY): 2017-04-01 – 2019-03-31
• Keywords: 腐食 / コンクリート / 鉄筋 / 不働態皮膜破壊 / 再不働態化 / 酸素還元 / 腐食加速試験

Outline of Final Research Achievements

In this study, the effects of stress and oxygen on corrosion behavior of steel rebar in concrete were investigated.
It was revealed that the localized corrosion on steel rebar in concrete can occur easily under tensile stress compared to that under no tensile stress when the concrete contains Cl-. In addition, the repassivation of steel rebar under tensile stress in concrete was hindered as the amount of Cl- in the concrete increases.
It was also revealed that the oxygen reduction reaction on the steel rebar surface is enhanced and the corrosion progress is enhanced as the amount of dissolved oxygen in concrete increases. Based on this finding, we have developed the hyperbaric-oxygen accelerated corrosion test which is a new accelerated corrosion test method.

Free Research Field

腐食

Academic Significance and Societal Importance of the Research Achievements

老朽化が深刻な問題となっているコンクリート構造物の劣化の主要因は鉄筋腐食である。これまで、鉄筋腐食に関して様々な研究がなされてきた。しかし、コンクリートが必ず晒される応力および酸素に関して、これらが腐食に及ぼす影響はほとんど明らかにされていない。本研究の成果は、これまで明らかにされてこなかった応力および酸素の影響を解明しただけでなく、これからのコンクリート構造物の建直しや建設の際の基準を考える一助となる社会的意義の大きな研究である。