Mining Waste Materials and Recycled Rubber Matrix for Rail Tracks under Cyclic Loading

Incorporating recycled materials (i.e., recycled rubber crumbs, RC) and mining wastes such as coal wash (CW) and steel furnace slag (SFS) in rail tracks helps to improve the track stability, while minimizing the stockpiling of these waste materials. This paper presents two novel methods to use the blended waste materials to replace conventional subballast/materials in rail track substructure, namely (1) SFS-CW-RC mixtures, and (2) CW-RC mixtures. Two series of cyclic triaxial tests were conducted to investigate the cyclic loading response of the mixtures with different RC contents, including deformation, resilient modulus, shear modulus, and damping ratio. Test results show that CW-RC mixtures are more compressive and present less resilient modulus and shear modulus than SFS-CW-RC mixtures for a given RC content. It is recommended that 10% RC is a preferable percentage for both mixtures according to their deformation behaviour, the resilient modulus, and the damping ratio.