Study On The Road Performance And Influencing Factors Of SBS-T Based Dry Modified Asphalt Mixes

SBS-modified bitumen is the most widely used modified bitumen in the industry and its production process is the traditional wet modification process.It has been proven that wet SBSmodified bitumen has so far suffered from modifier segregation and degradation by heat.SBST,as a new dry modifier,can be used to modify bitumen mixes,but as a new material,the modifying effect of dry SBS-T modifiers on bitumen mixes is not clear,nor are the factors affecting it.,which has become a technical bottleneck in the application of this technology,so this paper is a study of the above problems.The content and results are as follows:In this paper,the modifier dosing(3%,4.5%,6%,7.5%,9%),mixing temperature(150℃,160℃,170℃,180℃,190℃),wet mixing time(the 60 s,90s,120 s,150s,180s)and dry mixing time(30s,45 s,60s,75 s,90s)were used as test factors to design a four-factor,five-level A fourfactor,the five-level orthogonal test protocol was designed.The microscopic analysis and macroscopic tests were carried out to capture the modification effect of the dry SBS-T modifier in the mixing process of asphalt mixes(AC-16 and SMA-16),based on which the microscopic state and fluorescence microscopic area of the dry SBS-T modifier were observed and calculated using fluorescence microscopy,MATLAB,and Image J software.And the modification mechanism was analyzed.In the macroscopic aspect,high-temperature rutting test,lowtemperature bending test,water immersion Marshall test,and freeze-thaw splitting test were used to study the road performance of SBS-T dry modified asphalt mixes(AC-16 and SMA-16)under the coupling effect of multiple factors,and to determine the mixing and construction process of SBS-T dry modified asphalt mixes,to propose the quality control system of SBS-T dry modified asphalt mixes,and to control system and analyze its benefits.The results of the study are as follows: In the microscopic study,the dry SBS-T modifier gradually reaches a molten state as the mixing temperature rises,and during the mixing process with the aggregate,it will first adsorb on the surface of the aggregate and then gradually combine with the asphalt to form a uniform thickness of structural asphalt film wrapped around the aggregate,at a modifier dosing of 7.5%-9%,a mixing temperature of 180°C,a wet mixing time of the 90s-120 s,a dry mixing time of 45s-60 s,and a dry mixing time of 45s-60 s,The fluorescence microscopic area of the SBS-T modifier reached a larger value when the dry mixing time was 45s～60s,while the aggregate of AC-16 asphalt mix was more continuous and had a more uniform shearing and squeezing effect on the SBS-T modifier,and the fluorescence microscopic area was larger than under the SMA-16 asphalt mix.In the macroscopic study,the dry SBS-T modifier significantly improved road performance.The study recommended a mixing process with a modifier dose of 6%～7.5%,a mixing temperature of 170℃～180℃,a wet mixing time of 90s～120s and a dry mixing time of 60s～75s in hot and rainy areas in summer,and a modifier dose of 6%～7.5%,mixing temperature of 180°C,wet mixing time 120 s,dry mixing time 60s～75s.The dry SBS-T modification process omits the process of preparing modified asphalt,which can be tested from the source of materials such as dry SBS-T modifier,base asphalt,and aggregates,improving the quality of production and bringing certain management benefits;moreover,the omission of production equipment such as colloidal mills brings certain environmental and economic benefits.The results of the study are useful for tracking the effect of dry SBS-T modifier on asphalt.The results of this study are scientifically important for tracking the effects of dry SBS-T modifiers on asphalt and developing appropriate mixing processes that will play a role in the widespread adoption of dry SBS-T modification technology.