Toda Kanako, Kikuchi Ryosuke, Otake Tsubasa, Nishimura Satoshi, Akashi Yuzoh, Aimoto Michihiro, Kokado Takeshi, Sato Tsutomu
Division of Sustainable Resources Engineering, Faculty of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan.
Division of Field Engineering for the Environment, Faculty of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan.
Materials (Basel). 2020 Nov 30;13(23):5450. doi: 10.3390/ma13235450.
Dredged soils have been used as construction materials by alkaline activation with steel slag (steel slag-dredged soil mixtures) at harbors. Such mixtures develop strength chiefly by calcium silicate hydrate (C-S-H) formation by the pozzolanic reaction. However, the strength of such mixtures is unpredictable, and in some cases, mixtures have been too soft for the intended engineering application. An identification of strength development indicators would accelerate evaluation processes for strength development to facilitate and promote the utilization of such materials. This paper focuses on the relationship between the characteristics of soil organic matters in dredged soils and the strength development of the mixtures by a comparison of eight dredged soils collected from eight different Japanese harbors. The characteristics of the soil organic matters were identified to determine as indicators of mixtures with weak strength development, i.e., enriched sulfur content in extracted soil organic matter (humic acid) fraction, and the N/C ratio of humic acid similar to land humic acid standards. Increases in the validated fraction of dredged soils and steel slag by replacing fractions disadvantageous to construction resources would contribute to reduce waste production, which would lower the environmental impact of the use, aiming to achieve sustainable utilization of such materials.
在港口，疏浚土已通过与钢渣进行碱激发（钢渣 - 疏浚土混合物）用作建筑材料。此类混合物主要通过火山灰反应生成硅酸钙水合物（C - S - H）来发展强度。然而，此类混合物的强度难以预测，在某些情况下，混合物对于预期的工程应用而言过于软弱。确定强度发展指标将加快强度发展的评估过程，以促进和推动此类材料的利用。本文通过比较从日本八个不同港口采集的八种疏浚土，重点研究了疏浚土中土壤有机质特性与混合物强度发展之间的关系。确定土壤有机质的特性，以确定其为强度发展较弱的混合物的指标，即提取的土壤有机质（腐殖酸）部分中硫含量富集，且腐殖酸的N/C比与陆地腐殖酸标准相似。通过替换不利于建筑资源的部分来增加疏浚土和钢渣的有效部分，将有助于减少废物产生，从而降低使用过程中的环境影响，旨在实现此类材料的可持续利用。
