Study On Pavement Performance And Modification Mechanism Of SBS Modified Asphalt Mixture By Wet And Dry Pre-mixing Process

At present,wet pre-mixing technology is widely used to make SBS modified asphalt,which has comprehensive improvement effect on asphalt.However,SBS modified asphalt by wet process has some technical defects such as "SBS segregation,performance degradation by thermal decomposition ".The instant SBS-T modifier is a typical dry process SBS modifier,which can be directly placed into the mixing plant,avoidiong the problems of wet pre-mixing SBS modified asphalt to a certain extent.After rubbing by aggregate,the SBS-T modifier wrapped on the aggregate surface and diffused into the matrix asphalt to play a modifier role.As a new material and new process,the modification effect of SBS-T modifier and the performance of the modified asphalt mixture prepared by dry process need to be fully verified.It better develope comprehensive comparative study with SBS modified asphalt and asphalt mixture which are widely recognized by the road industry.On the basis of determining the processing parameters of modified asphalt and mixtures,this paper explored the modification effect of the SBS-T modifier and whether the SBS-T dry application can fully exert the modification effect.On the basis above,the road performance of SBS asphalt mixture by wet pre-mixing process and SBS-T asphalt mixture by dry pre-mixing process is compared.The micro-distribution of the two modifiers in asphalt was observed by fluorescence microscope,and the mechanism of Modified Asphalt was analyzed by infrared spectroscopy.Finally,the social benefits of the modified asphalt mixture of the two pre-mixing processes were analyzed.The results show that with the increase of modifier content,the performance of wet premixing SBS and wet pre-mixing SBS-T modified asphalt is obviously improved compared with base asphalt.SBS-T has the same modification effect as SBS modifier.Compared with the performance of the wet pre-mixing SBS-T modified asphalt mixture,the SBS-T modified asphalt mixture can perform well in the dry pre-mixing process.The performance of SBS asphalt mixture by wet pre-mixing process and SBS-T asphalt mixture by dry pre-mixing process has advantages and disadvantages.Specifically,the SBS modified asphalt mixture by wet pre-mixing process has better water stability,and the SBS-T modified asphalt mixture dry pre-mixing process has better high temperature performance and low temperature performance.Microscopic studies show that the modifiers in the SBS modified asphalt by wet pre-mixing process and SBS-T modified asphalt by dry pre-mixing process can be evenly distributed in the base asphalt,and the two modifiers and the asphalt are simply physically blended by improving the physical properties of the asphalt to achieve the effect of modification.According to the different modification processes,the dry pre-mixing process of SBS-T modification can be divided into three stages: rapid melting,viscous flow and fusion development.The wet premixing process of SBS modification can be divided into three stages: shear,swelling and development.Compared with the SBS modified asphalt mixture by wet pre-mixing process,the SBS-T modified asphalt mixture by dry pre-mixing process has the advantages of simple process,transparency in quality supervision,green environmental protection,etc.,which can avoid the technical defects and supervision difficulties of the wet pre-mixing process.The research results have certain guiding value for the popularization and application of SBS modified asphalt mixture by dry pre-mixing process.