Influence Of Rubber Powder Spacemovement Behavior On Basic Properties Of Asphalt Rubber At Mesoscopic Scale

At present,the research on asphalt rubber and concrete in China mainly focuses on the micro structure and macro performance,and there is no relation to the mesoscopic scale between macro and micro.In view of this situation,the paper studies the effect of the basic properties and the properties of rubber powder on the asphalt rubber.The main research contents are as followsFirstly,based on the research of the preparation parameters of asphalt rubber at home and abroad,combined with the three indexes,viscosity and thermal storage stability of asphalt rubber,the preparation parameters of asphalt rubber are determined:the amount of rubber powder is 27-30%,the preparation temperature is 160-180℃,the shear speed is 5000-5500r/min,the shear time is about 1 hour,and the development of rubber asphalt in 180℃ oven is 1 hour.For different grade asphalt,different amount of rubber powder is needed.For 70#and 90#base asphalt,the range of the mixture of the better performance is 21-24%and 27-30%respectively.There was no significant difference in the properties of asphalt rubber prepared at 160℃ and 180℃.The results showed that the main mechanism of compatibility stability is the asphalt rubber,and the process of oil absorption swelling high temperature shear compatibility dispersion is the main process.The addition of rubber powder can reduce the temperature sensitivity of asphalt and improve the thermal stability and anti-aging properties of matrix asphalt.Secondly,the Voronoi cell model composed of reference and similar colloidal powder is described at mesoscopic scale.Based on the discrete particle model,the shape of the dispersed rubber powder is set to be circular.At the same time,the rigid ball model is used to analyze the motion and static force of the contact particles in Voronoi cell model.The velocity,displacement and other static relations of the contact particles pairs,friction force and contact force increment are obtained.Finally,the effect of rubber powder on the mechanical properties of asphalt rubber and the influence of the movement of rubber powder in asphalt on the mechanical properties of asphalt rubber are simulated by ABAQUS software under constant load.The results showed that the mechanical properties of asphalt rubber are better than that of matrix asphalt,and the addition of rubber powder can reduce the stress inside the asphalt,and make the stress distribution more uniform,so as to enhance the asphalt offset The ability to resist deformation.The rotation movement and final distribution of rubber powder in asphalt will affect the mechanical properties of rubber asphalt.Among the selected feature points,the average stress of rubber powder at 0°is only 34.1%of 90°in space angle.In ideal condition,when all the rubber powder is in parallel state in asphalt,the rubber powder can enhance the mechanical properties of asphalt the most.