Construction of non-destructive estimation method of amount of surface chloride by measuring amount of water in concrete

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K15064
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 22010:Civil engineering material, execution and construction management-related
• Research Institution: Kisarazu National College of Technology
• Principal Investigator: Harada Kenji 木更津工業高等専門学校, 環境都市工学科, 助教 (20804876)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: 近赤外線分光法 / 自由塩分 / 水分 / 非破壊検査 / 表面塩分量

Outline of Final Research Achievements

Estimation method for the amount of surface chloride on concrete by measuring the amount of water in the concrete was investigated. It was clarified that the amount of water in concrete can be estimated by multiplying the difference in absorbance at wavelengths 1443 nm and 1365 nm by value that changes with W / C. It was clarified that in the higher humidity environment, amount of water in the concrete increases due to the chloride in the water. These show that in a high humidity environment, it may be possible to qualitatively estimate the amount of chloride in concrete from the amount of water in concrete estimated by NIRS.

Free Research Field

コンクリート工学

Academic Significance and Societal Importance of the Research Achievements

本研究により，コンクリート中の水分に溶解している塩分により，コンクリートは湿潤傾向になり，その傾向を近赤外線分光法により非破壊で測定できた．この結果は，コンクリート表面の水分量より，表面塩分量を推定できる可能性を示している．近赤外線分光法による水分量の推定は安全かつ迅速に行うことができるため，この研究結果は，今後のコンクリート構造物の塩害の判定の効率化に大きく貢献していくと考えている．今後も研究を継続していきたいと考えている．