Study on the Mechanism of Chloride Ion Supply for Marine Concrete Structures

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K15067
• 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: National Institute of Maritime, Port and Aviation Technology
• Principal Investigator: Tanaka Yutaka 国立研究開発法人海上・港湾・航空技術研究所, 港湾空港技術研究所, 研究員 (00792706)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 塩害 / 海洋構造物 / 維持管理 / 桟橋 / 数値解析

Outline of Final Research Achievements

To understand the mechanism of chloride ion supply for the underside of a superstructure of an open-type wharf, on-site investigation and wind flow simulation have been carried out in this study. From the results of this study, the spatial distribution of chloride ion supply and wind flow at the underside of the superstructure has a relation. In addition, the shorter the distance between the sea-water surface and the superstructure becomes, the stronger the wind flow becomes disturbed. This disturbance causes the complex wind flow directed toward slabs. Therefore, not only beams but also slabs, which have a long distance from the sea-water surface, have much surface chloride ion content. Moreover, the complex wind flow affects the spatial distribution of the surface chloride ion content at the underside of the open-type wharf.

Free Research Field

コンクリート工学

Academic Significance and Societal Importance of the Research Achievements

桟橋は非常に厳しい塩害環境下にあるため、特に上部工下面は塩害による劣化が進行しやすい。施設を長期に亘って安全に利用するためにも適切な維持管理が必要であるが、上部工下面の点検は、小型ボート等からの目視点検が一般的であり、労力を要する作業となる。本研究では、数値解析により塩化物イオンが供給されやすい箇所を概ね見当付けることができることを示した。この成果は、重点的に点検する箇所やセンサ設置箇所の選定等の維持管理の高度化および効率化に資するものであり、社会的意義が大きい。