Recycling of glass fibre reinforced polymer (GFRP) composite wastes in concrete: A critical review and cost benefit analysis

Abstract

The application of fibre reinforced polymer (FRP) composites has increased substantially in recent years as a result of need for lighter and stronger materials. Currently, the reuse and/or recycling of composite wastes is very limited while most of wastes are disposed of in landfill or incinerated. Recently, mechanical recycling, fluidised bed, and pyrolysis has been developed to recycle FRP composites, but yet to be fully commercialised. As an alternative recycling strategy, incorporating glass fibre reinforced polymer (GFRP) into concrete has shown a great potential from both economic and environmental perspectives. This paper systematically reviews the performance of recycling of GFRP wastes into concrete with respect to fresh properties, mechanical properties, durability, environmental and financial aspects. Results show that the effect of recycled glass fibre reinforced polymer (rGFRP) on concrete mechanical strength is associated with the content of waste material (fibre or resin rich) and physical properties (shape, density, hydrophilicity) of GFRP recyclates, as well as the amount of recyclates. For rGFRP powder, the filler effect combined with the pozzolanic reaction can improve interfacial transition zone strength, increasing mechanical strength. Recycled glass fibre has reinforcing effect to restraint cracks and can provide extra slip resistance to strengthen the bond, resulting in improvement of flexural strength. Recycling of GFRP waste in concrete reduces water absorption of the concrete, improving durability properties. Furthermore, this research presents outcomes of cost-benefit analysis and benefit-cost ratio on five common GFRP recycling methods. The results show that repurposing rGFRP in concrete can reduce the total required investment and increase net profit. Recommendations and future perspectives are also provided to allow a wider adoption of rGFRP repurposing from industrial waste and the development of a more sustainable life cycle.