Synergistic effects of waste plastic food tray as low-cost fibrous materials and palm oil fuel ash on transport properties and drying shrinkage of concrete

Waste plastic recycling is an essential step toward a green environment and a circular economy. Plastics, which are non-biodegradable polymers that come in various forms, have become an essential part of human life. The quick growth of the world's population has increased the need for plastics in different sectors such as food packaging. Consequently, adequate management of plastic waste recycling is critical to preventing environmental emissions from these wastes. In this study, experimental investigations were performed to determine the possibility of using polypropylene type of waste plastic food trays (WPFT) as low-cost fibres to improve the strength and durability performance of concrete. WPFT fibres with a length of 20 mm and dosages of 0–1% were used in concrete mixtures. The outcomes revealed that the inclusion of WPFT fibres decreased the workability of fresh concrete and the compressive strength. Despite a slight decrease in compressive strength, WPFT fibres' addition significantly increased the tensile strength by about 31% and reduced concrete's drying shrinkage by 35%. Besides, with fibre dosages of up to 0.6%, chloride penetration depth and sorptivity were remarkably decreased. The findings indicated that the use of WPFT fibres to manufacture sustainable concrete has a promising future. Concrete comprising waste plastics also leads to the conservation of natural resources and minimises solid wastes.