Upcycling fibre-reinforced plastic debris from abandoned fishing boats in the marine environment into innovative cementitious composite: A dual approach to natural resource conservation and consumer acceptance

Fibre-reinforced plastics (FRP) are widely used in the construction of commercial fishing boats, particularly in Asian countries, due to their durability and high strength. However, the lack of proper end-of-life disposal methods has led to the widespread abandonment of derelict boats, causing environmental harm through microplastic leaching and degrading coastal ecosystems. The study aimed to address this issue by evaluating a novel approach to convert derelict FRP fishing boats into cementitious composites, thereby reducing the consumption of natural sand and promoting long-term marine ecosystem sustainability. FRP debris were collected from fish landing centres along the Kerala coast. It was mechanically processed - shredded, pulverized, and sieved - to achieve a particle size of 0.3-1 mm. The resulting powder was used as a partial sand replacement (50%) in fabricating FRP-reinforced cementitious composites. Fourier transform infrared spectroscopy analysis confirmed the presence of glass fibre-reinforced polyester, with bulk density values lower than that of sand. Composition showed the powder primarily comprised glass fibre, making it a viable sand alternative. The resulting composite demonstrated mechanical properties comparable to traditional cementitious composites but with reduced specific weight, making it suitable for lightweight construction applications. Prototypes of architectural and beautification elements - such as vases, planter pots, and wall panels - were successfully developed using this composite. This study validated the feasibility of transforming environmentally problematic FRP debris derived from fishing boats into durable, value-added products. It highlights a sustainable solution that supports circular economy principles through effective debris valorisation and the conservation of finite natural resources.