Geotechnical improvement of soft clay using cockleshell ash and rice husk as stabilising agents
DOI:
https://doi.org/10.15282/construction.v6i1.13508Keywords:
Soft clay, Rice husk ash, Cockle shell ash, Undrained shear strength, Sustainable constructionAbstract
This study investigates the effectiveness of Rice Husk Ash (RHA) and Cockle Shell Ash (CSA) as sustainable stabilizing agents for improving the engineering properties of soft kaolinite clay. A series of laboratory tests were conducted to evaluate the physical and mechanical behaviour of the treated soil, including particle size distribution, specific gravity, Atterberg limits, Standard Proctor compaction, and undrained shear strength (USS). Kaolin samples were initially stabilized with varying dosages of RHA (3%, 6%, and 9%) to determine the optimum content for maximum strength improvement. The optimum RHA content was then combined with CSA at different proportions (3%, 6%, and 9%), and the specimens were cured for 1, 7, and 14 days. The results indicate that the addition of CSA to RHA-stabilized soil significantly influences the engineering properties of the clay. The inclusion of CSA reduced the specific gravity and optimum moisture content (OMC), while increasing the plasticity index (PI), maximum dry density (MDD), and undrained shear strength (USS). The highest strength improvement was observed for the mixture containing 9% RHA and 6% CSA after 7 days of curing, where the USS increased by 616.77% compared with untreated kaolin clay. This significant strength enhancement demonstrates the synergistic interaction between RHA and CSA when used as stabilizing agents. Overall, the findings indicate that the incorporation of CSA into RHA-stabilized kaolinite clay can effectively improve the mechanical performance of soft clay soils. The use of these waste-derived pozzolanic materials provides a sustainable and environmentally friendly approach for soil stabilization in geotechnical and construction applications.
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