Study on a new evaluation method for detecting concrete defects from the steel plate side by the principle of radiation scattering attenuation

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04801
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 23010:Building structures and materials-related
• Research Institution: Aichi Institute of Technology
• Principal Investigator: SEKO Shigeki 愛知工業大学, 工学部, 教授 (50507259)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: コンクリート / 空隙 / 中性子線 / ラジオアイソトープ / 遮蔽 / 集束 / 複合構造物 / RIカウント

Outline of Final Research Achievements

Using a radioisotope backscatter detector, the thermal neutron measurement results included the effect from the sides of the detector. To solve this problem, experimental tests were conducted. In the first, the characteristics of different moderators were investigated to choose the applicable material. In the second, when the selected moderator was attached to the void detecting system, tendency of radio-isotope count on mock specimen were examined experimentally. The experiments revealed that attached moderator to this device improves the void detection capability. In the composite structures, many steel stiffening members are attached inside of steel plates, which may be influencing factors during a nondestructive inspection. The effect of steel stiffening members inside composite slabs on RI counts was investigated, and steel rib plate influences the evaluation of the results decreasing RI counts as well as a void.

Free Research Field

建築構造・材料

Academic Significance and Societal Importance of the Research Achievements

本研究では、合成構造の部材にコンクリート打込み中または硬化後に鋼材の外側から測定した熱中性子量(RIカウント)等と、発生する欠陥部の関係式の基礎を確立することを目的とした。中でも、速中性子のエネルギー減衰を制御して検出効率を高める減速材と、中性子線遮へい材で放出範囲を制御する手法が欠陥の検出性能に及ぼす影響を明らかにすることができたこと、実験で選定した減速材や遮へい材をRI線源の周りに設置することで測定対象に絞り込んだ速中性子の放出が精度を高められることを実験により明らかとできた効果は大きい。鋼材を通して、即時的にコンクリートの欠陥部の位置・大きさを判別できる検査技術を確立に向けて前進できた。