Effect of red mud-based geopolymer binder on the strength development of clayey soil

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4. Effect of red mud-based geopolymer binder on the strength development of clayey soil

Disposal of mine tailings is a big concern for mining enterprises as it requires a large part of land for the construction of tailings storage facilities. Utilization of mine tailings as a geopolymer binder for soil stabilization could be a viable solution for its effective disposal. This article investigated the potential of red mud (bauxite tailings) as a geopolymer binder for its use in soil stabilization. Soil mixtures were prepared by partially replacing the soil with 10%, 20%, and 30% of red mud. Further, a mixture of NaOH and Na₂SiO₃ solutions prepared in a ratio of 30/70, 50/50, and 70/30 were utilized for activation. To examine the strength characteristics of stabilized soil, unconfined compressive strength tests were done after a curing period of 3, 7, and 28 days. Additionally, field emission scanning electron microscope images and energy dispersive X-ray spectroscopy were utilized to study the microstructural and elemental level changes occurring during the geopolymerization process. Based on the experimental findings, the compressive strength of bare soil could be increased from 0.35 MPa to 2.14 MPa by utilizing red mud as a geopolymer binder. This is attributable to the formation of N-A-S-H gel structures during geopolymerization which was further confirmed by the microstructural analysis. Furthermore, the highest improvement in compressive strength was achieved with the addition of 20% red mud activated by NaOH + Na₂SiO₃ solution mixed in 70/30 ratio. Overall, the current study shows that red mud can be utilized as a geopolymer binder for its usage in soil stabilization.

9th International Congress on Environmental Geotechnics (ICEG2023)

Resource Mining and Extraction