Utilising poly(ethylene terephthalate) wastes in concrete reinforcement: A sustainable approach to waste management, building materials and conservation

Carbon neutrality and carbon footprints’ reduction are global development goals that are intrinsically linked to waste management and are both achievable by wastes’ valorisations. Herein, 0.5%–10% grated poly(ethylene terephthalate) (PET) wastes were incorporated in M25 concrete as a sustainable and environmentally benign method of managing and/or reducing the nuisance of plastic wastes. The concrete was prepared by the weight-batching method in a 1:1:2 ratio of cement, sand and gravel, respectively; with a proportionate replacement of these constituents by PET to yield PET–concrete composites, after water-curing for 7–35 days. The addition of PET reduced the workability of the concrete by 33%–83% but furnished composites with improved compressive (0.66–2.89 N/mm2; 2.6%–10.6%) and tensile (0.04–0.64 N/mm2; 3.1%–79%) strengths, respectively; peaking with 2% PET content. Durability tests revealed favourable properties of reduced water sorptivity (13.2% → 8.4%) and improved resistance to acid attack (7.4% → 4.9%) but added susceptibility to seawater penetrability (1.5% → 3.1%), as PET contents increased, compared to the control composite (13.4%; 9.5%; 1.3%), respectively. A preliminary life cycle assessment was positive and in concurrence with the notion that incorporating PET into concrete is a feasible and green way of mitigating plastic wastes.