1- Circular Economy Practices in Engineering: Lime-Eggshell Powder Binders for Sustainable Soil Stabilization 

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(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

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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.

 

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Keywords: Lime stabilization, Expansive soil, Eggshell powder, Circular economy