Preparation And Performance Evaluation Of SBS/Crumb Rubber Powder Composite Modified High Viscosity Asphalt

In recent years,the drainage asphalt pavement has certain functions of drainage and noise reduction due to its characteristics of large porosity,good noise reduction performance,which meets the requirements of people for road safety and comfort,and has become an important direction of road development.High-viscosity modified asphalt has good high temperature performance and aggregate adhesion properties,which has become the key binder for the preparation of drainage asphalt road.Therefore,the preparation of high performance high-viscosity modified asphalt is very important for the development of asphalt pavements.In this paper,SBS,waste rubber powder and tackiness resin were added to 70#matrix asphalt to prepare the SBS/waste crumb rubber composite high-viscosity modified asphalt by the full swelling,high temperature shear,and then development process;then the optimal content of each modifier was determined by the range and variance analysis of orthogonal experiment.Finally,the modification mechanism,storage stability,high-temperature viscosity characteristics,high-low temperature and fatigue performance based on PG classification method and fatigue properties of different high viscosity modified asphalt were systematically and deeply studied.The test results are as follows:(1)By the orthogonal test,the optimal content of each modifier for the SBS/waste crumb rubber composite high-viscosity modified asphalt were determined to be 7%linear SBS,12%waste rubber powder and 4%tackiness resin.(2)By analyzing the change of functional groups in the infrared spectrum,it was found that the asphalt had both chemical reaction and physical modification in the process of mixing with SBS,waste rubber powder and tackiness resin.By analyzing the microscopic morphology and surface roughness of atomic force microscopy,it can be seen that the addition of various modifiers can form a stable network structure in the asphalt system,resulting in a large number,small area and uniform distribution of "bee phase structure",which improved the root mean square roughness of asphalt.Therefore,the SBS/waste rubber powder composite high-viscosity modified asphalt has good adhesion with aggregate.Then,the heat flow curves of matrix asphalt,SBS/waste rubber powder composite high-viscosity modified asphalt and SINOTPS high-viscosity modified asphalt were obtained by DSC test Compared with the glass transition temperature Tg and the area of heat absorption peak,it can be seen that the glass transition temperature Tg of matrix asphalt became smaller after high viscosity composite modification,indicating that the temperature of asphalt under high elastic state reduced by adding modifier,and the low temperature performance was improved Meanwhile,the reduction of heat absorption area showed that the addition of modifier makes the internal structure of asphalt more stable and its thermal stability was improved.(3)The viscosity-temperature relation curves of SBS/waste rubber powder composite high-viscosity modified asphalt,SINOTPS high-viscosity modified asphalt and Shell high-viscosity modified asphalt were established by DSR viscosity-temperature sweeping.The analysis results showed that SBS/waste rubber powder composite high-viscosity modified asphalt had the highest high-temperature viscosity,but the poor construction workability.So,it is necessary to add a warming agent to reduce its viscosity at the same temperature,so as to reduce the construction temperature and mixing temperature.Through the PG specification evaluation,the analysis of the high temperature,low temperature and fatigue performance of different high-viscosity modified asphalt found that the high temperature and low temperature,medium temperature fatigue resistance of the modified asphalt had been improved significantly after the addition of various modifiers,and the SBS/waste rubber powder composite high-viscosity modified asphalt had the best performance.