The use of recycled rubber in ballasted railway tracks: A review

The disposal of waste tire rubber (WTR) is an environmental challenge, and a significant amount of waste is sent to landfills. However, modern railway tracks depend on rubber materials for their resilient elements. Therefore, extensive research is being conducted to investigate the reuse of WTR to form track components. To better understand this body of research, this paper presents a state-of-the-art review of the application of WTR in railways. First, the use of WTR for components close to the rail is explored with a focus on railroads, rail dampers, and level-crossing applications. Next, rubber–concrete sleepers and under-sleeper pads are discussed before exploring ballast-related solutions such as under-ballast mats and ballast mixed with rubber crumbs/chips. Finally, numerical simulation methods are discussed, including finite element constitutive models and the discrete element method. The paper concludes with suggestions for future research.