# End-of-Life Tyres: Comparative Life Cycle Assessment of Treatment Scenarios
## 1 Introduction and State of the Art  
It is estimated that the annual generation of waste tyres amounts to 1.5 billion whole-tyres worldwide [1], contributing to the huge number of tyres already placed in landfill and stockpiles. Due to recent global recognition and strong environmental awareness, many authorities have imposed strict rules and regulations regarding this waste product to prevent excessive stockpiles and landfill operations [2]. According to the European Tyre and Rubber Manufacturers' Association (ETRMA), every year more than three million tonnes end-of-life tyres (ELTs) are collected and treated. The rate of ELTs treated for material recycling and energy recovery has significantly increased in the last two decades and already in 2009, 95% of ELTs arising on the EU market were successfully diverted from landfill. In most European nations, the handling of ELTs is managed by an Extended Producer Responsibility, a principle that gives to the tyres producers and importers the responsibility for a correct ELT management. In Italy this principle has been ratified with the Dlgs 152/20,006 and the ministerial decree n. 82/2011. Currently, every year around 350,000 tons of ELTs are managed in Italy, collected from cars, two-wheeled vehicles, trucks, up to large quarry vehicles and agricultural vehicles. Producers guarantee the collection and the sending to materials/energy recovery programs for 100% of the ELTs legally placed on the spare parts market The management of ELTs is therefore in line with the circular economy principle, aiming at avoiding or, at least, reduce waste and manage raw materials' scarcity through the continual use of resources. According to the hierarchy adopted in the EU for waste management (Directive 2008/98/EC), the tyre retreading offers high potential for circularity, through direct reuseof part of worn tyres and a lifetime extension. However, the retreading market is in decline, down by 20% since 2010 [3]. When it is not possible to avoid the waste, the directive suggests that generally the priority should be given to the recovery of materials (recycle and/or reuse). Currently, in Italy, the 56% of ELTs is sent to material recovery. Specifically, according to Ecopneus [4], secondary raw materials from ELTs currently finds employment in sport flooring (especially as synthetic grass for soccer fields, surface coats for tennis, basketball and horse-riding), children's playgrounds, acoustic insulation, rubber articles (e.g., shoe soles) and civil works (e.g., asphalts). The other 44% is sent to energy recovery through co-incineration in existing cement klins (using scrap tyres as replacement of traditional fuels) or dedicated incineration. In this context, this paper aims to analyse and compare the environmental impacts of two common scenarios of ELT treatments: the recycling of ELT for the realisation of Rubber Asphalt (RA) and the incineration for energy recovery. Impact calculations will be carried out according to the standardised [5; 6] methodology of Life Cycle Assessment (LCA). Life cycle assessment (LCA) applied to these materials has rapidly expanded over the last few years as a tool able to capture and handle complexities and interdependencies typically characterizing modern integrated waste management systems [7; 8; 9]. With reference to the European situation and the most recent legislation published by the European Commission (EC), i.e., the Waste Directive 2008/98/EC (EU, 2008), LCA is used to rationalize technological choices and to define management strategies; in less advanced regions, with a similar approach, LCA is used to develop measures required to implement more integrated solid waste management systems, and to reach EU directives [10]. The LCA methodology according to ISO 14,040 is worldwide accepted and appreciated because it allows an objective evaluation of the environmental performances of products and processes [11].