Innovative reinforcement: Assessing strength features of waste microplastics reinforced backfills in sustainable mine waste management

Abstract

The growing concern over plastic waste and its environmental impact, coupled with challenges in managing mine tailings, necessitates innovative solutions to enhance sustainability in mining operations. The current investigation explores the prospective use of waste microplastics as reinforcement within cemented tailings backfill (CTB) by addressing waste management and structural improvement of backfill. Waste Polyethylene terephthalate (PET) and polyvinyl chloride (PVC) microplastic were incorporated at various content levels (0 %, 10 %, 20 %, 30 %) and particle sizes (100 mu m, 500 mu m, 3-4 mm) and analysed through UCS and SEM tests. Laboratory findings reveal that the optimum mechanical performance is achieved with a 10 % substitution of 100 mu m waste PET particles, leading to an 8.3 % rise in strength gain and a balanced combination of energy storage and dissipation. However, higher substitution levels and larger particle sizes decreased strength due to increased porosity and weak interfacial bonding between waste microplastic particles and cementitious matrix. These research findings provide a dual benefit of waste valorization and mine waste management, preparing for viable and potentially cost-effective mine backfill practices.