Testing Research Of Waterproof Asphalt Material On The Ballastless Track Subgrade

As the high-speed railway has the ability of celerity and stability, it developed wildly in China. Subgrade must be have enough strength and stiffness, only this , it enable to ensure the train keep high-speed motion . geotechnical materials as the main body filling material of subgrade has enough bearing capacity in dry environment, but it will be lost strength and stability when water erode into subgrade. So, we take an layer on the subgrade to protect the subgrade from that surface runoff like rainfall and snow water and so on soften the subgrade.Through the analysis and research of road asphalt mixture and hydraulic asphalt mixture, we determine the five important properties of waterproof asphalt mixture and relevant measuring method of the index parameters, the index include: permeability, density, water stability, low temperature crack resistance, and high temperature stability. Moreover, we definite the major and minor relationship of them.According to the nature and feature of waterproof asphalt mixture, we can determine test item and measure standard of the raw material. Through the comprehensive comparative analysis of three types of asphalt mixture characteristics (include: AC-5, AC-10 and AC-13) that each of them designed graded curves respectively close to upper bound,middle line and lower bound ,it sum to nine curves ,in five index of waterproof asphalt mixture, we can definite the most reasonable type of waterproof asphalt mixture is SAMI-10. In addition, we formed the mix proportion design that take permeability coefficient and porosity as the the border, and intensity ratio of frozen and melted and Marshall stability as optimizing factor, and the linear contractive Modulus as test index .At last, through the analysis and summarizing of the key point in the experiment process, we determine the different test methods and relevant operation points about the permeability coefficient of asphalt mixture.