Thermal performance of the solar reflective fluorocarbon coating and its effects on the mechanical behavior of the ballastless track

Abstract

A novel solar reflective fluorocarbon coating was proposed to improve the performance of ballastless tracks of high-speed railways at high temperature. Firstly, experiments were carried out to investigate the influence of the solar reflective fluorocarbon coating on the temperature field of coated concrete structures. Secondly, a non-linear finite element model of the ballastless track incorporating the non-linear properties of concrete and a cohesive zone relationship of interfaces between track components was established, and the numerical model was verified by on-site monitoring results. Then, based on the experimentally measured temperature fields, the efficiency of the solar reflective fluorocarbon coating on reducing temperature deformation of the track was quantified by finite element analysis, and the combined action of initial track component defects and bond properties between track components on the mechanical behavior of the coated track was analyzed. Finally, the influence of thermal performance of different coatings on mechanical behavior of the track was systematically investigated. Results show that the solar reflective fluorocarbon coating can reduce the surface temperature and the temperature gradient of the coated track by 10% and 14% respectively. After applying the solar reflective fluorocarbon coating to the ballastless track, the maximum slab end arching displacement, the rise of slabs in the lateral direction, and the maximum longitudinal stress of the concrete joints can be reduced by 20%, 19%, and 13% respectively. The combined action of initial track component defects and the interfacial bond strength should be considered when studying the thermal deformation of the ballastless track. Slab end arching displacements are mainly influenced by the surface temperature of the slabs.