Study on the driving force of salt weathering and salt solution transfer in porous material

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K22445
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0304:Architecture, building engineering, and related fields
• Research Institution: Kyoto University
• Principal Investigator: Takatori Nobumitsu 京都大学, 工学研究科, 助教 (70880459)
• Project Period (FY): 2020-09-11 – 2022-03-31
• Keywords: 多孔質材料 / 塩化ナトリウム溶液 / 透水係数 / 変水位透水試験 / 吸水実験 / 塩溶液

Outline of Final Research Achievements

The objective of this study is to investigate the driving force of salt solution migration in porous materials. The main results are as follows:
1) The permeability of NaCl solution in saturated tuff was measured by the Falling-head method. It was found that there is a range of salt concentrations for which the permeability cannot be reproduced by considering only the density and viscosity coefficients of the salt solution.
2) Saline water absorption experiments were conducted with the same type of tuff used in experiment 1). The results showed that, as in the Falling-head method, the saline water absorption rate was faster in low-salt concentration NaCl solution than in pure water.

Free Research Field

建築環境工学

Academic Significance and Societal Importance of the Research Achievements

建築物および文化財の保存において、塩類風化など塩による諸問題への対策は年々その重要度が高まりつつある。多孔質材料中における塩の移動を数値解析により精緻に再現できる技術の開発は、塩類風化の対策を考える上で重要な役割を担う。本研究は、多孔質材料中における塩溶液の移動に着目しその移動性状を精緻に検討したものであるが、これまで建築分野で考えられてきた純水の移動理論とは異なり、塩溶液の移動にはその濃度が大きく寄与することが明らかとなった。これらの成果は今後建築物や文化財の塩類風化を予測するうえで重要な示唆を与えるものと考えられる。