Research On The Performance Of High Content Rubber-SBS Compound Modified Asphalt And Mixture

With the increase in the number of motor vehicles in our country,on the one hand,the traffic channelization effect of asphalt pavement has become increasingly prominent,and the performance of a single polymer-modified asphalt cannot meet the current requirements.On the other hand,the demand for solid waste treatment and effective utilization of waste tires,which are consumables for motor vehicles,is also increasing day by day.For this reason,this paper proposes to use the two widely used modifiers,rubber and SBS compound modification to give full play to their respective advantages,and further increase the amount of rubber in the compound modified asphalt,maximize the modification effect of SBS and rubber,and further improve the property of the asphalt and mixture.This paper focuses on the high content rubber-SBS compound modified asphalt and mixture,and studies its preparation method,performance characteristics,micro-mechanism and road performance of the mixture.First of all,based on the common content of rubber-SBS compound modified asphalt,the influence factors of its property were clarified through research,and the rubber fineness was determined to be 40 mesh and 60 mesh the SBS content was 2%-3%made the best asphalt performance.On this basis,the viscosity of the asphalt was reduced to an appropriate range by cracking and desulfurizing the rubber and pretreatment of the modifier.Based on this,a compound modified asphalt with a rubber content of up to 42%was prepared.Subsequently,the rheological properties and aging properties of high content rubber-SBS compound modified asphalt were studied.The results show that the high content of rubber and compound modification can raise the elastic components of asphalt,improve the rut factor and recovery rate of asphalt,reduce the irrecoverable creep compliance,and improve the high temperature resistance to deformation of asphalt and the recovery ability after deformation.Fatigue performance and aging performance tests show that increasing the amount of rubber through cracking has a certain negative impact on asphalt fatigue and UV aging resistance,but after compound modification,these properties of asphalt were improved due to the cross-linking of SBS and rubber.Then,the mechanism of high content rubber-SBS compound modified asphalt was studied using four material testing techniques.Fluorescence microscope and scanning electron microscope images show that the vulcanization system of the rubber was opened due to the addition of the cracking agent in the high content rubber-SBS compound modification.It formed a network structure in the asphalt,and the SBS was connected with the rubber to form a dense system.X-ray photoelectron spectroscopy（XPS）test results showed that the S-S and S-C chemical bond content of the rubber decreased under the action of the cracking agent,and new S-O bonds were formed.Infrared spectroscopy tests show that SBS and ordinary rubber modified separately,and the process of compound modification of them were physical modification.After adding the cracking agent,the rubber produced a chemical reaction of desulfurization and cracking,which made the characteristic peaks of functional groups near1510cm^-1and 1232cm^-1in the rubber modified asphalt disappear.Afterwards,the road performance of high content rubber-SBS compound modified asphalt mixture was studied.The results show that by raising the amount of rubber on the basis of ordinary compound modification,the high and low temperature performance and fatigue resistance of the asphalt mixture were improved,but the water stability was reduced.And whether it is a high content rubber or a compound modified asphalt mixture,the gap gradation had better overall road performance,so it is more recommended to use the gap gradation.Finally,the compound modified asphalt and mixture were applied to the project engineering,showing good road performance and usability.Comprehensive research shows that the high content of rubber-SBS compound modified asphalt has better performance and higher application value.