Full definition
Tire granulate, also referred to as crumb rubber, is a material derived from the mechanical processing of end-of-life tires (ELT). This process involves shredding, grinding, and screening to produce rubber particles of various sizes, enabling diverse industrial applications. The granulate is categorized based on particle size: coarse chips (25-100 mm) are often utilized in civil engineering projects as fill; granulate (1-10 mm) is suitable for sports surfaces and molded products; crumb rubber (0.5-4 mm) finds use in playground surfaces and modified asphalt; while fine powder (<0.5 mm) is intended for reuse in rubber compounds. The processing retains the inherent properties of tires, such as abrasion resistance and elasticity, primarily from SBR (styrene-butadiene rubber) and NR (natural rubber) blends, which often include carbon black for enhanced durability.
The applications of tire granulate are extensive and varied. In playground safety surfaces, it meets the EN 1177 standard for critical fall height compliance, ensuring safety for children. In sports flooring and running tracks, it complies with IAAF certification, providing a reliable surface for athletes. Moreover, as infill for artificial turf, it adheres to FIFA Quality certification, enhancing performance and durability. Additionally, tire granulate is increasingly incorporated into rubber-modified asphalt mixtures, which are characterized by either gap-graded or open-graded compositions that not only reduce noise but also improve the flexibility of the pavement. Other uses include anti-vibration mats and various molded products such as mats, bumpers, and gym tiles, typically bonded with 10-15% polyurethane binder to ensure stability and performance.
From an environmental perspective, tire granulate plays a significant role in waste management by diverting approximately 1 billion ELT from landfills annually. This recycling effort not only reduces landfill pressures but also contributes to sustainable practices in construction and sports industries. Compliance with ASTM D6270 outlines the requirements for tire-derived materials in civil engineering, mandating the use of steel-free and fiber-free grades for applications related to sports and flooring to ensure the safety and longevity of the surfaces. Given the increasing global focus on sustainability, tire granulate represents a valuable resource in the circular economy, promoting the reuse of materials and reducing environmental impact.