Microstructural and strength analysis of lower Himalayan soil in Arunachal Pradesh using biomedical waste as additives

The escalating generation of biomedical waste poses critical environmental and health challenges globally. This study investigates the sustainable utilization of shredded nitrile gloves (NG) and Plaster of Paris (POP) as stabilizing additives for silty sand soil from the landslide-prone Nirjuli-Banderdewa corridor in Arunachal Pradesh, India. Comprehensive geotechnical characterization included compaction tests, Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), and advanced microstructural analysis using Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). Nitrile gloves were incorporated at 0.35%, 0.5%, and 1% by dry weight, while POP was added at 3%, 6%, and 9%. Results demonstrated that the optimal combination of 0.5% NG and 6% POP achieved a 109% increase in UCS and more than doubled both soaked and unsoaked CBR values compared to untreated soil. Microstructural analysis revealed enhanced particle bonding, reduced porosity, and improved fabric integrity through bridging mechanisms and cementitious gel formation. The stabilized soil meets IRC specifications for heavily trafficked road subgrades, demonstrating a viable circular economy approach for biomedical waste management while addressing geotechnical challenges in the seismically active Himalayan region.