## 1 Introduction
The urgency to address these issues is underscored by global initiatives such as the European Union's 20-20-20 targets, which include reducing greenhouse gas (GHG) [27] emissions and improving energy efficiency [3]. As industrial processes, particularly in the mineral products industry, contribute significantly to GHG emissions, finding sustainable solutions [3] for ELT recycling becomes imperative [7]. Additionally, the utilization of recycled ELTs in composite materials, specifically in conjunction with concrete replacing raw materials, such as sand [28], presents an eco-friendly approach. Concrete and tire recycling product crumb rubber offers opportunities for sustainable construction materials, contributing to waste management objectives and promoting a cleaner environment [29]. As an application, crumb rubber can be used in the manufacture of different products or as a raw material replacement [15] input for cement composites, which gives the material different physical-mechanical properties [30], such as ductility, sound absorption, and elasticity [31]. These properties allow us to use cement composites on highways or railways to build sound protection walls to reduce or avoid sound pollution in inhabited areas, and shoreline protection [15] during floods with ice stacks gives durability and fixability at the same time. Therefore, this leads to the saving of the soil and environment. The tire manufacturing industry accounts for a substantial portion of natural and synthetic rubber consumption globally, and the proper management of ELTs has become a critical aspect of sustainable supply chains [32]. Developing environmentally and financially feasible systems for recycling ELTs [33] and establishing markets for ELT-derived products are ongoing challenges. Incorporating sustainable materials into construction is a growing priority, particularly in the context of reducing the environmental impact of resource-intensive industries, such as concrete production. Previous research using the OpenLCA software 2.0.2 has demonstrated the significant environmental benefits of integrating recycled materials into construction practices. Specifically, calculations reveal that replacing traditional river sand with crumb rubber--derived from end-of-life tires (ELTs)--by volume can substantially reduce the environmental impact. River sand weighs 2300 kg/m\({}^{3}\), whereas crumb rubber weighs 1050 kg/m\({}^{3}\). By treating crumb rubber as waste with negligible environmental impact during its life cycle, the substitution results in a remarkable 24.06% reduction in Global Warming Potential (GWP100a). These findings emphasize the potential of crumb rubber to serve as an eco-friendly alternative in cement composites, contributing to reduced carbon emissions [34] and promoting sustainable waste management practices [35]. However, despite these gains, the physical-mechanical properties of the material show a 40% decrease, highlighting the need for further material testing and refinement to ensure structural integrity. Balancing environmental [36] advantages with functional performance, thus, remains a key challenge for advancing the use of crumb rubber in sustainable construction [37; 38]. In this research paper, the diverse perspectives on ELT recycling are explored, considering environmental and technological aspects. The focus extends to evaluating the impact of ELT recycling on reducing carbon emissions, promoting a circular economy, and enhancing the sustainability of cement composites. Through a comprehensive review and calculations, insights into the current state of ELT recycling worldwide, available technologies, and their environmental implications are provided.