Cement-asphalt Composite Binder Creep Damage Characteristics And Constitutive Model

Cement-asphalt composite binder(CA compound binder)is a kind of organicinorganic composite binder widely used in the construction of high-speed railway in China.It is mainly used in the cement mortar cushion of slab ballastless track as binder,and plays an important role in supporting,regulating and reducing vibration of slab ballastless track.Under the action of temperature and wheel load,the creep behavior of CA composite binder has an important influence on the stability of track structure.In this paper,the creep and creep recovery properties of CA composite binder are studied,and the effect of creep damage on its mechanical properties is analyzed.A viscoelastic-plastic mechanical model considering creep damage is established,and the material ratio and test method are determined.By introducing fractional derivative model and plastic element,RKB-S mechanical model is constructed.Based on this model,creep and creep compliance formulas are deduced,and a method for determining the stress threshold of plastic elements is proposed.The raw materials and their proportions of CA composite binder were determined,and the creep and creep recovery test,stress scanning test and other experimental research programs were formulated.The creep and creep recovery tests of CA composite binder were carried out,and the creep and creep recovery characteristics were analyzed.The effects of stress level,temperature and A/C on creep mechanical properties of CA composite binder were analyzed.Quantitative analysis was carried out based on experimental data,and the effects of different factors on elastic,viscoelastic,viscoelastic and plastic properties of CA composite binder were clarified.The creep damage evolution equation of CA composite binder was established,and the influence of creep damage on viscoelastic-plastic mechanical parameters was analyzed.Based on creep and creep recovery tests,the plastic strain threshold of CA composite binder at different temperatures was determined.By fitting and analyzing the creep and creep recovery test results,the accuracy of the RKB-S mechanical model is verified.The effects of stress level,temperature and material ratio on the viscoelastic-plastic properties of CA composite binder were studied through the analysis of viscoelastic-plastic mechanical parameters.The evolution of viscoelastic damage of CA composite binder was studied,and the difference of creep damage on viscoelastic and elastic properties was analyzed.A damage variable describing the damage of elastic,viscoelastic and viscoelastic properties of CA composite binder is proposed.The effect of stress level on creep and creep recovery rate of CA composite binder was analyzed.The effect of stress level on viscoelastic-plastic mechanical properties of CA composite binder was studied.The influence of creep damage on the viscous and elastic properties of CA composite binder was studied,and the influencing factors and mechanism of the damage difference were analyzed.