Evaluation on the Performance of Asphalt Concrete for the Railway Substructure

The dense-graded asphalt concrete has been a potential waterproofing material for the subgrade in high-speed railway in China. As a viscoelastic material, asphalt concrete can improve the bearing capacity and stability of the track structure. The main purpose of this paper is to evaluate the material performance of asphalt concrete substructure from different aspects. According to the environmental conditions and functional requirements, the mix design of asphalt concrete was completed based on the Marshall design method. The laboratory tests were conducted to evaluate the performance of asphalt concrete substructure, including rutting test, fatigue test, low-temperature bending test, immersion Marshall test, freeze–thaw split test, dynamic modulus test, and permeability test. The linear viscoelastic behavior of asphalt concrete at different temperatures and loading frequencies was then discussed, and it was observed that the asphalt concrete substructure had good energy dissipation capacity at the loading frequencies caused by the high-speed train. The tensile strain at the bottom of asphalt concrete substructure was analyzed by the finite element model. The results indicated that the service life increased as the thickness of asphalt concrete substructure increased. Therefore, the proposed asphalt concrete in this paper is a promising material for the sustainable substructure of high-speed railway.