Durability of recycled waste plastic aggregate concrete

The durability of waste plastic aggregate (WPA) concrete was investigated. Concrete specimens prepared with varying proportions and shapes of WPA were prepared and their durability was evaluated. The bond between WPA and cement mortar was evaluated using scanning electron microscopy. The water absorption of WPA concrete was more than that of normal concrete. The water absorption of fibre-, flake- and granule-type WPA concrete was 16-28%, 15-35% and 14-32% more than that of control concrete, respectively. The chloride permeability (CP) of WPA concrete decreased; however, it was almost in a similar range (2200-3550 Coulombs) in all the specimens. Corrosion initiation was delayed in WPA concrete, except in the fibre-type WPA. The corrosion rate (CR) decreased by 34-82% in granule-, 23-60% in flake- and 11-20% in fibre-type WPA concrete compared to the control concrete. The compressive strength of concrete exposed to heat/cool cycles for 3 months decreased by 2-19% as the quantity of WPA increased indicating debonding between WPA and the cement mortar due to thermal variations. Due to its improved durability, concrete with up to 50% WPA can be used in construction of structures with low to moderate durability requirements.