Abstract:
This study addresses challenges of cracking and durability faced by conventional dense
graded asphalt mixtures (DGA) in hybrid railway tracks. Stone mastic asphalt (SMA),
known for superior performance but hindered by cost, is explored as alternative with
recycled polyethylene terephthalate (PET) to enhance durability of the tracks while
balancing investment and maintenance costs. Conventional asphalt binder was employed,
and its optimal content (OBC) was determined through the marshal design method. An
appropriate value for recycled PET was identified to selectively substitute a portion of the
OBC. Subsequently, the PET-infused mix underwent thorough assessments for
susceptibility to moisture damage, rutting, and fatigue failure. The findings were utilized
to analyze the response of the aforementioned tracks through numerical analysis with 100
scenarios varying asphalt and ballast layers thicknesses, axle wheel loads, and subgrade
moduli using Ansys software. Experimental results reveal that a 10% PET substitution
maintains SMA stability while exhibiting good resistance to fatigue and water damage.
The numerical analysis results demonstrate a favourable track response, particularly for
moderate to stiffer subgrade moduli, suggesting that SMA mix with recycled plastics could
serve as a viable alternative to DGA for enhancement of the lifespan of hybrid bituminous
ballasted tracks at a reasonable investment cost.
