Laboratory evaluation on the long-term performance of crumb rubber asphalt mixture for elastic track bed

Crumb rubber (CR) asphalt mixture (CRAM) presents a promising strategy for mitigating environmental risks and enhancing waste recycling. This paper provides a systematic long-term performance assessment of CRAM for its application in elastic track beds, focusing on vertical stability, low-temperature crack resistance, and the effects of freeze-thaw cycles, aging, and their coupled influences. Results show that the optimal expansion ratio and split tensile strength of CRAM are achieved after a 45-min swelling. Compared with virgin asphalt mixture, the addition of 3 % CR leads to a slight increase in the accumulated damage strain and the Dissipated Pseudo Strain Energy of CRAM under vertical loading, thereby demonstrating competitive long-term vertical stability. Moreover, while CR may accelerate the initiation of low-temperature cracks, it appears to mitigate the crack propagation rate. Regarding resistance to crack initiation, CRAMs exhibit satisfactory performance against long-term freeze-thaw cycles and aging, excluding their coupled effect. The residual performance of CRAM can maintain over 70 % of its initial performance. However, CRAM with 6 % CR demonstrates deficiencies in crack propagation resistance after aging. Cost analysis reveals that CRAM provides a 30 % reduction in materials and construction costs compared to polyurethane reinforced track beds. By recycling crumb rubber from waste tires, CRAM significantly reduces emissions and land encroachment. This study holds the potential to guide the utilization of CRAM for elastic track beds in railway engineering.