Asphalt Concrete Layer to Support Track Slab of High-Speed Railway

Abstract

Asphalt concrete (AC) is a traditional material that is used to construct highway pavement and offers the advantages of good bearing capacity, waterproofing, shock absorption, and noise reduction. In recent years, AC also has been used to construct railway infrastructure as part of the rapid development of high-speed rail in China. The study presented in this paper focused on the material composition and mechanical response of railway asphalt concrete (RAC) on the basis of mechanistic models and laboratory experiments. According to the material test results, the air voids of the material RAC-25 used for railway infrastructure should be controlled from 1% to 3%. The optimal asphalt content should be obtained from parameter tests. The recommended asphalt content should be less than 5.8%. Load-bearing infrastructure with the use of RAC-25 to replace partially the surface layer of subgrade, which was a stabilized layer on top of the subgrade, may yield a better performance. This design was No. 1 asphalt concrete railway substructure (ACRS-1). On the basis of the test results, the model with a 12-cm depth of graded gravel subgrade surface layer replaced by RAC-25 showed much better capacity and stability than other models. By comparison, the model reinforced by RAC-25 showed a higher K30 value, less deformation, good temperature sensitivity, and better loading performance. In summary, the ACRS-1 reinforced by RAC-25 was found to be a suitable type of structure for high-speed railway infrastructure.