Numerical and experimental investigation of reduced temperature effect on asphalt concrete waterproofing layer in high-speed railway

The thermal fatigue cracking of asphalt concrete waterproofing layer (ACWL) in high-speed railway is mainly caused by the daily reduced temperature effect. In this study, numerical and experimental investigations on this effect were respectively conducted through the determination of surface temperature field, finite element modelling (FEM), and experiments using the customized overlay test (OT). The results indicated the thermal condition in Northern China was more severe for ACWL compared with that of other regions. The stress concentration effect on ACWL surface was mainly attributed to the temperature variation, average temperature, and viscoelastic behaviour of asphalt concrete. In addition, the OT results indicated the internal damage might happen in ACWL without obvious surface feature. Finally, the OT was in consistent with FEM analysis regarding internal stress distribution and fatigue characteristics, and thus could be used as a feasible test method to evaluate the thermal fatigue of ACWL.