Sustainable End-of-Life Tyre Management: A Comprehensive Analysis of Environmental Impacts and Crumb Rubber Integration in Composite Concretes

Abstract

The research explores pollution prevention strategies associated with end-of-life tyres (ELTs) through sustainable practices, focusing on repurposing ELTs into crumb rubber (CR) for use in composite concretes for civil engineering applications. Three disposal approaches are considered: recycling into crumb rubber for use in cement composites to enhance acoustic properties, incineration for cement production, and landfill disposal. The study aims to assess the environmental impact of each method, particularly in terms of carbon dioxide (CO₂) emissions during the recycling phase, utilizing the OpenLCA program for a comprehensive life cycle analysis. The primary objective is to provide insights into the sustainability of incorporating recycled rubber in concrete mixes as fine aggregate to improve concrete acoustic and shock absorbance properties. The research also gathers data on CO₂ emissions from ELT incineration for cement production and the environmental implications of ELT’s landfill disposal. By comparing these three strategies, the study offers a holistic perspective on the environmental ramifications of ELT management. Notably, a recent study highlights the energy recovery and CO₂ emissions from ELT incineration, demonstrating the potential benefits of recycling. The research identifies a gap in existing studies, emphasizing the need to consider the entire life cycle, including the transportation and use stages. Notably, the use stage significantly contributes to environmental impacts, with carbon emissions ranging from 550 to 840 kg CO₂ eq., per car tyre. Additionally, a proposed inventory analysis method evaluates greenhouse gas emissions from Portland cement concrete pavement construction, revealing that raw material production accounts for most emissions. The findings of this research are providing valuable insights for policymakers, industry professionals, and environmentalists aiming for sustainable practices in the construction sector. By allocating a fraction of tyre production CO₂ emissions to obtain raw material for concrete composites, the study suggests a potential avenue for reducing environmental impact. Further calculations using the OpenLCA program may refine these recommendations.