Mechanics, durability, and microstructure analysis of marine soil stabilized by an eco-friendly calcium carbide residue-activated coal gangue geopolymer AITranslate

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DOI：https://doi.org/10.1016/j.cscm.2023.e02687

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Highlights ● Marine soil with CG-CCR geopolymer showed excellent engineering performance. ● Geopolymer content, initial water content, and curing age control the enhancement. ● Durability is affected by the geopolymer content and initial water content. ● Mass loss is a prominent factor in strength reduction after wetting-drying cycles. ● Microstructure of marine soil was improved by reaction products of geopolymer. Constructing infrastructure on soft soils demands the implementation of ground improvement. This study proposed an eco-friendly method of stabilizing marine soil using a calcium carbide residue (CCR)-activated coal gangue (CG) geopolymer derived from industrial waste. Laboratory experiments were conducted to investigate the mechanical properties, durability performance, and stabilization mechanisms of stabilized marine soils under multiple wetting-dry cycles. The results highlighted the effectiveness of CG-CCR geopolymer by a content of 15% to achieve satisfactory strength gain over the engineering requirements. However, the largest decrease in strength (71.89%) was observed when the initial water content was beyond 1.5 times the liquid limit (LL). The optimum solution was proposed to have a geopolymer content of 15% or an initial water content of 1.25·LL to exhibit the highest resistance to strength decay after 12 cycles. Compared with water intrusion, mass loss had a more significant effect on soil strength deterioration. The formation of noncrystalline or amorphous-phase reaction products effectively filled intergranular pores and reduced the void space between soil particles, improving the mechanical properties. The CG-CCR geopolymer was demonstrated to offer a promising solution for soil improvement in geotechnical engineering and waste reduction in industry as a soil stabilizer.