Valorization of plastic waste aggregate in concrete: A study on durability and microstructural properties.

Efficient valorization of plastic waste is widely investigated by numerous researchers. The need for an alternate to conventional aggregate in concrete production has led to the evolution of numerous artificial aggregates. This research investigates the impact of adverse environmental exposure conditions in plastic waste aggregate concrete. Conventional concrete of M30 grade designed as per IS- 10262 (2019) specification serves as control mixture. The conventional fine aggregate was volumetrically substituted at 5, 10 and 15 percentages with recycled waste plastic granule aggregate. Further, these three variants of plastic aggregate concrete mixtures were introduced with an additional substitution of 10% of glass cullet. The concrete mixtures were subjected to water absorption, sorptivity, chloride penetrability, acid and alkali exposure conditions to test their durability characteristics. The 15% PWA concrete mixture exhibited good resistance to water absorption which accounts to be 5.7% less when compared to water absorption of conventional concrete (M0) mixture. The compressive strength loss experienced in acid exposed concrete cubes was noted as 51.3% in conventional concrete mixture and 34.5% in M15PA10G mixture (15% PWA with 10% glass cullet). The 10% PWA concrete mixture exhibited 48.7MPa compressive strength after 60 days of sulphate immersion, which accounts for 43% gain in strength as compared to its normal 28 days cured compressive strength, 34MPa. Concrete mixtures with 10% glass cullet performed with very low chloride ion permeability of 300 coulombs to 500 coulombs. SEM analysis revealed a strong bond between plastic aggregate and concrete matrix. Concluding that, the plastic aggregate concrete mixture along with glass cullet satisfies the basic durability characteristics of normal strength concrete.