Improving Sand–Bentonite Hydromechanical Performance With Shredded Facemask and Colloidal Nanosilica

Sand–bentonite (SB) serves a crucial role as a landfill liner for waste containment and environmental protection. However, the challenge of insufficient strength in SB liners poses risks of failure and hazardous substance release. To address this, our study introduces an innovative approach by incorporating the shredded facemask (FM) and colloidal nanosilica (CN) to investigate their combined effects on enhancing the hydromechanical performance of SB mixtures. The research encompassed a wide range of tests, such as unconfined compressive strength (UCS), free swell, 1D consolidation, and 3D volumetric shrinkage tests. To explore the geochemical compositions and microstructures of both untreated and treated SB samples, microstructural analysis techniques were utilized, including X‐ray fluorescence, X‐ray diffraction, Fourier‐transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Results show that the inclusion of FM improves both strength and dilative behavior, with an even more significant enhancement in strength observed upon the CN treatment. Optimal increases in UCS of 167% and 194% were achieved after treating with 0.5% FM and 15% CN in 10% and 15% bentonite contents for 28 days, respectively. Furthermore, notable improvements were also observed in swelling control, volumetric strains, and shrinkage limits. Additionally, the study met the prescribed benchmarks for hydraulic conductivity and adhered to the generally accepted minimum strength criteria for soil liners. Finally, FTIR and SEM analyses confirmed improved interlocking between SB particles and the viscous gels formation, leading to enhanced SB performance. The findings offer significant perspectives into the hydromechanical performance of FM‐CN‐treated SB and introduce an innovative approach featuring a robust design, contributing to more efficient and environmentally friendly practices in the treatment of SB.