Sustainable recycling of end-of-life tyres in civil (geotechnical) engineering applications: turning issues into opportunities in the New Zealand context

Abstract

End-of-life tyres (ELTs) are non-reusable tyres in their original form. They enter a waste management system based on product/material recycling and energy recovery or go to disposal. In New Zealand, only 30% of the 5 million ELTs produced yearly are recycled. The residual 70% of ELTs are mainly disposed of through landfill, stockpiles or illegally disposed. However, ELTs cannot be considered as a simple waste to be disposed of. If mechanically sheared into granulated tyre rubber, ELTs may find use in many civil engineering applications. In this paper, key environmental issues associated with ELTs poor management and recycling processes are first described and discussed with reference to the New Zealand context. Then, the potential reuse of ETLs in geotechnical applications is demonstrated based on the results on a multi-disciplinary feasibility study conducted jointly at University of Canterbury and at the Institute of Environmental Science and Research Ltd. (ESR).