Upgrading Recycled Aggregates in Concrete by Using Waste Plastics

The current study investigates the potential upgradation of recycled coarse aggregates using plastics to be used in concrete. The study investigates the properties of plastic-coated recycled aggregates (PRA) in comparison to the properties of recycled aggregates (RA) and conventional coarse aggregates (CA) using different tests including specific gravity, impact strength, hardness, shape, elongation, and water absorption. The plastic-coated recycled aggregates (PRA) were produced from adding melted PP waste (~180 ℃) to demolished aggregates at 5% (w/w) followed by mixing for homogenous coating on the surface. The PRA exhibited 10–24% higher specific gravity, impact strength and hardness with reduced water absorption (by 50%) as compared to RA. The study further investigated the strength and durability properties of concrete cubes produced using PRA as compared to RA and CA. Although the RA exhibited failures for M15, M20 and M25 at compressive strengths of 13.8, 18.6, 20.4 N/mm² respectively after 28 days curing, cubes made of PRA exhibited around 21–40% higher values relative to RA and insignificant difference as compared to that of CA. Moreover, the cubes made of PRA also exhibited relatively better results in slump test, Vee Bee test, and Water absorption test. However, chemical leachability and toxicity studies are necessary before commercial application.