Study Of SBS Dispersion And Its Effect On The Performance Of The Modified Asphalt

In this paper, SBS modified asphalts were prepared by Qinhuangdao AH-90 asphalt and linear SBS(T6302), which were produced in Qinhuangdao and Du shanzi respectively. Fluorescence microscopic analysis technology was used to observe the SBS modified asphalts which were prepared by the shearing method and solvent method, and the basic performance of modified asphalt were measured by using conventional methods, such as softening point, ductility, penetration, viscosity and so on. The influencing factors including shearing time, the type and dosage of compatibilizers, the proportion of SBS and solvent, the kinds of master batch, solvent content of SBS and stabilizer on the dispersion of SBS in asphalt were studied. Besides, the effect of microstructure on the properties of modified asphalt and SBS were investigated.Comparing fluorescence samples preparation methods showed that the hot drops method was relatively simple and could satisfy the requirements of the quantitative analysis. The optional preparation condition of the hot drops method was that hot asphalt was put on the cover glasses molding at 100 ℃ and heated for 10 min and the microstructure of SBS in asphalt could be better observed under this condition.As the aromatics content of compatibilizers increased, the softening point of the SBS modified asphalt increased, while ductility decreased. Conversely, as the saturates concent of compatibilizer increased, the softening point declined and ductility increased. It showed that aromatic released hard segment of SBS, saturates released soft segment of SBS. When the aromatics content of compatibilizers was 55 %, and compatibilizer content was 5 %, the particle size of SBS in asphalt was smallest, and the stability was the best.The SBS master batchs prepared by solvent method were used to produce modified asphalts instead of SBS. It could effectively reduce the asphalt heat temperature and weaken the shear strength in modified asphalt production process, and the diameter of SBS particles was distributed from 1 to10 μm. With the increase of the proportion of cyclohexane in the mother liquor, SBS in asphalt not only spread evenly, but the particle size became smaller. From fluorescent microscope images of modified asphalt, basic properties and storage stability, it was concluded that the properties of modified asphalt were better using toluene to prepare master batch, but the improvement was not obvious.Relative to physical modification, the performance of the modified asphalt made by chemical modification was improved. The softening point, ductility and viscosity increased and penetration reduced. The phase interface between SBS and asphalt disappeared and SBS presented a three-dimensional network structure, which satify the requirement of the storage stability.