International Scientific Journal of Civil and Infrastructure Engineering (ISJCIE) - Vol.2
ISSN 2981-8168
https://doi.org/10.56601/ISJCIE-V2
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Contents:
1- Circular Economy Practices in Engineering: Lime-Eggshell Powder Binders for Sustainable Soil Stabilization
(Pages 1-17), 10.56601/ISJCIE-V2-1st
Reem Alqaisi, University of Technology Sydney (UTS), Sydney, Australia
Thang Minh Le, University of Technology Sydney (UTS), Sydney, Australia
Hadi Khabbaz, University of Technology Sydney (UTS), Sydney, Australia
ABSTRACT: Australia is among the top egg-producing nations, with an annual output exceeding 4 billion eggs. The resulting eggshell waste poses a significant environmental issue as it often ends up in landfills. This problem can be mitigated by converting eggshells into eggshell powder (ESP) for use as a soil-stabilizing agent. Due to its high calcium oxide content, ESP shows promise as a pozzolan for stabilizing expansive soils. This research presents a proposed innovative method to improve lime stabilization effectiveness in expansive soils by incorporating different percentages of eggshell powder. An experimental program is carried out to explore the influence of ESP and hydrated lime on the strength properties of expansive soils with high plasticity and swelling potential. Soil samples, composed of kaolinite, bentonite, and Sydney fine sand, were subjected to extensive geotechnical tests, including conductivity, Atterberg limits, shrinkage limits, compaction, unconfined compressive strength (UCS), shear strength, and swelling potential tests. The study found that a mix of approximately 5% lime and 5% ESP effectively improved soil characteristics for subgrade applications, evidenced by increased UCS and shear strength, and reduced plasticity and swelling potential. This research yields valuable insights into assessing the potential applications of eggshell powder in geotechnical engineering contexts. Eggshell powder can be tailored to ameliorate the strength and stabilization attributes of expansive soils in regions where optimal subgrade performance is overlooked. A circular economy analysis indicates that repurposing eggshell waste can yield environmentally sustainable raw materials while alleviating landfill pressure.
Keywords: Lime stabilization, Expansive soil, Eggshell powder, Circular economy
2- A Review of Vertical Inclusions as Ground Improvement Techniques for Foundations in Transport Infrastructure
(Pages 18-55), 10.56601/ISJCIE-V2-2nd
Yashar Salehi, Faculty of Engineering and Information Technology, University of Technology Sydney, Australia
Hadi Khabbaz, Faculty of Engineering and Information Technology, University of Technology Sydney, Australia
ABSTRACT: In today's world, constructing roads and embankments on soft ground has become increasingly challenging due to urbanization and population growth. Soft soils often deform excessively under loads, requiring improvement to ensure stability. Vertical inclusion systems provide solutions for constructing transportation structures on soft soils. These systems can be divided into semi-rigid inclusions (e.g., stone columns) and rigid inclusions (e.g., concrete-injected columns and auger-cast piles). In recent years, concrete-injected columns (CIC) have gained popularity as a viable ground improvement technique for roads and rail projects. Additionally, the use of geosynthetic encasements has been widely preferred by geotechnical engineers to overcome issues associated with stone columns in very soft clays. The aim of this paper is to briefly describe the vibro stone column (VSC) and CIC methods and their applications as sustainable ground improvement techniques in some transportation projects around the world. Case studies, numerical analyses, and experimental findings are reviewed to compare their effectiveness and identify unexplored areas. Vertical inclusions effectively reduce settlement and enhance the load-bearing capacity of weak ground. However, their application is site-specific. Stone columns are suitable for liquefiable soils, while CIC is preferred for sensitive structures where vibrations must be minimized. Furthermore, some recommendations are given regarding future studies and the combination of the above-mentioned techniques to achieve optimum results while considering the cost-effectiveness of road or rail projects.
Keywords: Ground Improvement, Bi-modulus Columns, Vertical Inclusion, Concrete Injected Columns, Stone Columns
1- Improving the Engineering Properties of Expansive Soils Using Lime and Eggshell Powder: A Characterisation Study
(Pages 56-75), 10.56601/ISJCIE-V2-3rd
Reem Alqaisi, University of Technology Sydney (UTS), Sydney, Australia
Thang Minh Le, University of Technology Sydney (UTS), Sydney, Australia
Hadi Khabbaz, University of Technology Sydney (UTS), Sydney, Australia
ABSTRACT: Eggshell waste management is an emerging environmental concern in Australia, primarily due to the substantial quantities generated by the poultry industry. Inadequate disposal practices can result in adverse environmental impacts, including unpleasant odours, increased insect activity, elevated disposal costs, and pressure on limited landfill capacity. To address these challenges, eggshells can be processed into eggshell powder (ESP), which is rich in calcium carbonate (CaCO3) and has potential as a soil-stabilising agent. This study presents a cost-effective approach for stabilising expansive soils, which are susceptible to significant volume changes with fluctuations in moisture content. An experimental program was undertaken to evaluate the influence of ESP and hydrated lime on the strength characteristics of expansive soils. The soils were simulated using kaolinite, bentonite, and Sydney fine sand to reflect typical regional soil conditions. A series of tests, including Indirect Tensile Strength (IDT), California Bearing Ratio (CBR), and bender element testing, were conducted following varying curing periods. The bender element tests were employed to determine the small-strain shear modulus (Gmax), thereby providing insight into the stiffness development over time. The results demonstrate that a combination of 5% ESP and 5% lime substantially enhances the engineering properties of the soil, yielding superior IDT, CBR, and Gmax values compared to lime-only mixtures. This research underscores the viability of ESP as a sustainable additive for improving the strength and stability of expansive soils, particularly in applications where exceptionally high subgrade performance is not a critical requirement.
Keywords: Soil Stabilisation, Eggshell Powder, Hydrated Lime, Expansive Soil