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Development of Sustainable Ground Materials by Utilizing Agro-waste Aggregate for Soil Enhancement in the Subgrade Layers
http://hdl.handle.net/10076/0002001765
http://hdl.handle.net/10076/000200176571f190eb-395b-4e26-a4e4-1525221b6721
| 名前 / ファイル | ライセンス | アクション |
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2025DB0906.pdf (13.7 MB)
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| アイテムタイプ | 学位論文 / Thesis or Dissertation(1) | |||||||
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| 公開日 | 2026-03-23 | |||||||
| タイトル | ||||||||
| タイトル | Development of Sustainable Ground Materials by Utilizing Agro-waste Aggregate for Soil Enhancement in the Subgrade Layers | |||||||
| 言語 | en | |||||||
| 言語 | ||||||||
| 言語 | eng | |||||||
| 資源タイプ | ||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_db06 | |||||||
| 資源タイプ | doctoral thesis | |||||||
| アクセス権 | ||||||||
| アクセス権 | open access | |||||||
| アクセス権URI | http://purl.org/coar/access_right/c_abf2 | |||||||
| 著者 |
Shehata, Atef Abdelmageed Abdelmageed
× Shehata, Atef Abdelmageed Abdelmageed
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| 著者（ヨミ） | ||||||||
| 姓名 | シーハタ, アティフ アブドゥルマジドゥ アブドゥルマジドゥ | |||||||
| 言語 | ja-Kana | |||||||
| 抄録 | ||||||||
| 内容記述タイプ | Abstract | |||||||
| 内容記述 | In today's global construction industry, strengthening weak and expansive soils is becoming increasingly critical due to urbanization, climate change, and the need for resilient infrastructure. While effective, Traditional soil stabilization techniques rely heavily on cement and lime, which are costly and contribute significantly to carbon dioxide emissions and environmental degradation. This thesis presents a comprehensive study on the sustainable stabilization of expansive soils using rice husk ash (RHA) as a cement-reducing aggregate integrated with minimal cement dosages in stratified subgrade layering approach. By repurposing RHA, an abundant agricultural byproduct often underutilized in rice-producing regions, this research offers an innovative and eco-friendly solution to enhance soil properties, reduce material costs, and mitigate the environmental impacts of conventional stabilization methods. The research evaluates sixteen different soil mixtures, each prepared with varying proportions of RHA (2%, 4%, and 6%) and cement (2%, 4%, and 6%). These mixtures were applied in three subgrade configurations: upper, lower, and double layers. The primary aim is to determine the optimum mix and layering technique that maximizes shear strength, compressive strength, and overall load-bearing capacity while reducing the dependence on cement. A robust experimental program was implemented to achieve this, comprising mechanical tests such as the California Bearing Ratio (CBR), Triaxial Compression Test, Unconfined Compressive Strength (UCS), and Standard Proctor compaction tests. Additionally, advanced microstructural analyses were conducted using Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) to investigate the formation of cementitious hydration products and the evolution of the composite’s microstructure over time. The experimental results demonstrate that incorporating RHA significantly improves the soil's mechanical properties. Notably, specimens containing 6% RHA combined with 6% cement in the double subgrade layer exhibited the highest angle of internal friction. These findings highlight the potential of using stratified layering techniques to target the most critical subgrade zones, thereby enhancing soil reinforcement and overall structural stability. The integration of RHA in the stabilization process offers multiple benefits. Environmentally, it provides a sustainable avenue for managing agricultural waste, reducing the overall carbon footprint by partially substituting cement, a high-energy and CO₂-intensive material. Economically, the use of locally sourced RHA in regions such as Egypt, which is the focal case study in this thesis, offers a cost-effective alternative to imported construction materials. Egypt, facing significant challenges with expansive soils and rapid urbanization, can particularly benefit from this innovative stabilization technique by achieving higher soil strength and durability at reduced material and environmental costs. The stratified application of the soil-RHA-cement composite further distinguishes this research. By explicitly targeting the subgrade layers' upper, lower, and double layers, the method ensures that the stabilizing agents are optimally distributed where they are most needed. This targeted approach not only enhances the mechanical performance of the soil but also prevents the formation of weak planes that can lead to differential settlements and eventual structural failure. The experimental data indicate that when treated with higher proportions of RHA and cement, the upper subgrade layers exhibit the most substantial cohesion and shear strength improvements. Additionally, the double-layer configuration shows promise in achieving high deviatoric stresses, which is critical for the performance of pavements and other infrastructural elements subjected to dynamic loads. From a microstructural standpoint, the improvements observed in the 28-day cured specimens are profound. The SEM images illustrate a transition from a loosely bound, porous matrix in the early curing stage to a densely cemented and well-integrated composite structure. This densification is accompanied by a significant reduction in micro-cracks and voids, thereby enhancing the overall integrity and durability of the soil. The corresponding EDS analysis confirms that the improved microstructure is associated with an increased presence of key chemical components, namely, silicon and calcium, that drive the formation of the cementitious gels. These chemical and physical transformations collectively contribute to the enhanced geotechnical performance of the stabilized soils. The implications of this research are far-reaching. By demonstrating that using RHA as a sustainable stabilizing agent can significantly improve the mechanical properties of expansive soils, the study provides a viable pathway toward more environmentally friendly and cost-effective ground improvement practices. The approach meets the structural demands of modern infrastructure. It aligns with global sustainability initiatives, such as the United Nations Sustainable Development Goals (SDG 9), emphasizing the need for resilient and sustainable industrialization and infrastructure. Furthermore, the research offers a scalable model adapted to various geographical and climatic conditions. While the experimental work was conducted under controlled laboratory conditions, the principles and methodologies developed in this thesis have broad applicability. In regions like Egypt, where expansive soils and resource limitations pose significant challenges, the findings offer a promising solution that leverages locally available materials to enhance soil stability and support infrastructure development. Integrating advanced analytical techniques, such as SEM and EDS, provides a comprehensive understanding of the underlying mechanisms, laying a strong foundation for future research and practical applications in sustainable geotechnical engineering. this thesis contributes significantly to sustainable ground improvement by presenting a novel approach to soil stabilization that combines the benefits of rice husk ash with minimal cement dosages in a stratified application. The research highlights the benefits of enhancing soil mechanical properties and promoting environmental sustainability through waste valorization and reduced cement consumption. The findings demonstrate the proposed method's effectiveness in improving shear strength, compressibility, and load-bearing capacity and provide critical insights into the microstructural and chemical mechanisms driving these improvements. This work sets the stage for further innovations in soil stabilization and paves the way for developing robust, low-carbon solutions for infrastructure in expansive soil regions worldwide |
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| 言語 | en | |||||||
| 内容記述 | ||||||||
| 内容記述タイプ | Other | |||||||
| 内容記述 | 本文/Graduate School of Bioresources, Mie University | |||||||
| 内容記述 | ||||||||
| 内容記述タイプ | Other | |||||||
| 内容記述 | 188p | |||||||
| 書誌情報 |
発行日 2025-09-25 |
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| フォーマット | ||||||||
| 内容記述タイプ | Other | |||||||
| 内容記述 | application/pdf | |||||||
| 著者版フラグ | ||||||||
| 出版タイプ | VoR | |||||||
| 出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||||
| その他の言語のタイトル | ||||||||
| その他のタイトル | 農業廃棄物骨材を活用した持続可能な地盤材料の開発と路床層における土質改良 | |||||||
| 言語 | ja | |||||||
| 出版者 | ||||||||
| 出版者 | 三重大学 | |||||||
| 出版者（ヨミ） | ||||||||
| 値 | ミエダイガク | |||||||
| 学位名 | ||||||||
| 学位名 | 博士(学術) | |||||||
| 学位授与機関 | ||||||||
| 学位授与機関識別子Scheme | kakenhi | |||||||
| 学位授与機関識別子 | 14101 | |||||||
| 学位授与機関名 | 三重大学 | |||||||
| 学位授与年月日 | ||||||||
| 学位授与年月日 | 2025-09-25 | |||||||
| 学位授与番号 | ||||||||
| 学位授与番号 | 甲学術第2347号 | |||||||
| 資源タイプ（三重大） | ||||||||
| 値 | Doctoral Dissertation / 博士論文 | |||||||
