Mechanics, durability, and microstructure analysis of marine soil stabilized by an eco-friendly calcium carbide residue-activated coal gangue geopolymer
Jianfeng Li, Yi Shan, Pengpeng Ni, Jie Cui, Yadong Li, Jinwen Zhou
Abstract
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.