| The filling material of embedded track is the key to affect the vibration and noise reduction performance of the structure,because the rail in the structure is continuously supported by the elastic cushion plate and the polymer material,and the rail is completely embedded in the polymer filling material.Generally,the material is required to have high damping loss factor and suitable elastic modulus.At present,there are a series of problems in the performance,cost and environmental protection of polyurethane filling materials that are widely used.As a high-strength and high-damping material,epoxy asphalt is feasible to replace polyurethane,but there are also shortcomings such as insufficient flexibility and poor low-temperature performance.Therefore,this paper combines the demand of embedded track structure and the characteristics of epoxy asphalt,and chooses to introduce large chain flexible curing agent and waste tire particles to modify epoxy asphalt in the system to ensure that the material can meet the performance requirements of track structure.Firstly,the requirements of tensile,compression and damping of the material were formulated according to the research content,and the raw materials and methods of material preparation were clarified.Uniaxial compression,uniaxial tensile,compressive stress relaxation and dynamic mechanical analysis(DMA)were used as the test methods to evaluate the performance of the material.Orthogonal test was designed to determine the distribution ratio of the material group.The control specimens with different rubber content and mesh were set to explore the influence of two factors on the performance of the material.Secondly,properties of the compression and tensile test data of materials at ordinary temperature and low temperature are compared,it is considered that the ratio of compatibilizer: flexible curing agent: epoxy resin: modified asphalt =1:1.25:1.4:0.4 are expected to meet the performance requirements.The test level was encrypted and the orthogonal test again was conducted on this basis.The results showed that the optimal ratio was 1:1.2:1.4:0.4.Moreover,low curing temperature,reducing asphalt content,increasing the proportion of flexible curing agent and reasonable epoxy resin content are helpful for the material to meet the performance requirements.Thirdly,the mechanical tests of materials with different rubber content and mesh were completed.The results show that rubber content should be 8%～24%,and the higher the content is,the better the compression,tensile,relaxation and low temperature toughness of the material are.While reducing the content can improve the damping loss factor and broaden the effective temperature range.The larger the rubber mesh,the less sensitive the material is to low temperature,and the relaxation characteristics are inversely proportional to the mesh.The specimens with 60 mesh and 80 mesh rubber powder showed good mechanical properties.According to the mechanical test data of epoxy asphalt materials for filling,the hyperelastic and viscoelastic constitutive models of epoxy asphalt materials were established,and the hysteresis characteristics of materials were analyzed.Based on dynamic thermomechanical analysis(DMA)and time-temperature equivalence principle,the main curves of storage modulus and phase angle are obtained,and the mechanical properties of the material under high frequency are predicted.The results show that the model can describe the mechanical properties of the material well,and the material can maintain good mechanical properties under high frequency load.Finally,Abaqus software was used to carry out the simulation analysis of compression test and relaxation test,and the rationality of material parameters was verified.The track structure model is established,and the anti-overturning stability of the structure is analyzed.It is considered that the epoxy asphalt material has certain stability when applied to the embedded track structure,which lays a foundation for the application research of subsequent materials. |
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