Investigation of the mechanics of rail seat deterioration and methods to improve the abrasion resistance of concrete sleeper rail seats

A sustained increase in gross rail loads and cumulative freight tonnages on heavy haul railways, as well as increased interest in high- and higher-speed passenger rail development, is placing an increasing demand on railway infrastructure and its components. Rail seat deterioration (RSD) refers to the degradation of the material at the contact interface between the sleeper's rail seat and the pad that protects the bearing area of the sleeper.RSD continues to be identified as one of the primary factors limiting concrete sleeper service life, particularly in heavy haul operations. This paper includes results from two laboratory experiments that used test setups and protocols and were designed to isolate the abrasion mechanism. The first experiment was used to acquire quantitative and qualitative data related to the frictional properties of rail pad materials sliding on a concrete surface under various normal loads. The second experiment quantified the abrasion resistance of rail seat materials. Results confirmed that abrasion is a feasible RSD mechanism and that the frictional characteristics at the contact interface between the rail pad and concrete rail seat appear to have an impact on the transfer of forces and relative movement, and thus the abrasion mechanism. Also, the abrasion resistance of the rail seat's surface can be improved by grinding off the top cement paste layer to expose a hard aggregate surface and also by applying an epoxy coating to the surface. Increasing the service life of railway track components will facilitate capacity building on heavy haul, mixed-traffic and passenger railways around the world by reducing maintenance costs and decreasing the demand for maintenance windows.