{"title":"Mixture design for eco-friendly hybrid clay treated with two stabilizers based on water absorption and retention of stabilizers","authors":"Shafique Raihan Shovon , Alula Kassa , Ryo Sekine , Kimitoshi Hayano , Yoshitoshi Mochizuki","doi":"10.1016/j.sandf.2023.101403","DOIUrl":null,"url":null,"abstract":"<div><p>Major challenges are encountered when using high-water-content clays as construction materials owing to their low shear strength and high compressibility. Processes, such as sun drying and stabilization using chemical agents, can address the problems met with these clays during their conveyance and reuse. However, natural dehydration is a time-consuming process, and chemical stabilization can lead to an increase in the hydrogen ion index (pH) of the surrounding environment. Thus, the aim of this study is to improve the performance of high-water-content clay using a combination of green and byproduct materials, specifically bamboo chips and fly ash, which are cost-effective and eco-friendly. No previous study has attempted to design a mixture for the purpose of improving the performance of clay based on the water absorption and retention performance of stabilizers. In this study, the water absorption and retention rate (<em>W</em><sub>ab</sub>), which is the mass of the water absorbed and retained by 1 g of each stabilizer, was measured by removing the unabsorbed and unretained water through filtration under vacuum suction. A series of Cone Index tests were conducted on clay, separately treated with bamboo chips and fly ash, and the tests demonstrated a correlation among the Cone Index (<em>q</em><sub>c</sub>), <em>W</em><sub>ab</sub>, and amount of stabilizer added (<em>A</em><sub>st</sub>). A novel mixture design was proposed for hybrid-treated clay, using the two types of stabilizers in the composite, based on parameter <em>β</em>, which is defined as the sum of the product (<em>W</em><sub>ab</sub>/100)×(<em>A</em><sub>st</sub>/100) of each stabilizer used in the hybrid-treated clay. The results of the Cone Index tests performed on the hybrid-treated clay showed that the proposed mixture design can predict the combinations of certain amounts of each stabilizer needed to attain the target <em>q</em><sub>c</sub> with minimal errors. The results of pH measurement tests indicated that the hybrid-treated clays produced by the proposed mixture design were more eco-friendly than fly ash-treated clays. Furthermore, the theoretical maximum CO<sub>2</sub> fixation capacities of the hybrid-treated clays were evaluated to assess their feasibility as CO<sub>2</sub>-fixing materials.</p></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"64 1","pages":"Article 101403"},"PeriodicalIF":3.3000,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0038080623001324/pdfft?md5=83a5141bb9096c8c45d4927c40aa9e7a&pid=1-s2.0-S0038080623001324-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Soils and Foundations","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0038080623001324","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, GEOLOGICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Major challenges are encountered when using high-water-content clays as construction materials owing to their low shear strength and high compressibility. Processes, such as sun drying and stabilization using chemical agents, can address the problems met with these clays during their conveyance and reuse. However, natural dehydration is a time-consuming process, and chemical stabilization can lead to an increase in the hydrogen ion index (pH) of the surrounding environment. Thus, the aim of this study is to improve the performance of high-water-content clay using a combination of green and byproduct materials, specifically bamboo chips and fly ash, which are cost-effective and eco-friendly. No previous study has attempted to design a mixture for the purpose of improving the performance of clay based on the water absorption and retention performance of stabilizers. In this study, the water absorption and retention rate (Wab), which is the mass of the water absorbed and retained by 1 g of each stabilizer, was measured by removing the unabsorbed and unretained water through filtration under vacuum suction. A series of Cone Index tests were conducted on clay, separately treated with bamboo chips and fly ash, and the tests demonstrated a correlation among the Cone Index (qc), Wab, and amount of stabilizer added (Ast). A novel mixture design was proposed for hybrid-treated clay, using the two types of stabilizers in the composite, based on parameter β, which is defined as the sum of the product (Wab/100)×(Ast/100) of each stabilizer used in the hybrid-treated clay. The results of the Cone Index tests performed on the hybrid-treated clay showed that the proposed mixture design can predict the combinations of certain amounts of each stabilizer needed to attain the target qc with minimal errors. The results of pH measurement tests indicated that the hybrid-treated clays produced by the proposed mixture design were more eco-friendly than fly ash-treated clays. Furthermore, the theoretical maximum CO2 fixation capacities of the hybrid-treated clays were evaluated to assess their feasibility as CO2-fixing materials.
期刊介绍：
Soils and Foundations is one of the leading journals in the field of soil mechanics and geotechnical engineering. It is the official journal of the Japanese Geotechnical Society (JGS)., The journal publishes a variety of original research paper, technical reports, technical notes, as well as the state-of-the-art reports upon invitation by the Editor, in the fields of soil and rock mechanics, geotechnical engineering, and environmental geotechnics. Since the publication of Volume 1, No.1 issue in June 1960, Soils and Foundations will celebrate the 60th anniversary in the year of 2020.
Soils and Foundations welcomes theoretical as well as practical work associated with the aforementioned field(s). Case studies that describe the original and interdisciplinary work applicable to geotechnical engineering are particularly encouraged. Discussions to each of the published articles are also welcomed in order to provide an avenue in which opinions of peers may be fed back or exchanged. In providing latest expertise on a specific topic, one issue out of six per year on average was allocated to include selected papers from the International Symposia which were held in Japan as well as overseas.
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