Relationship Between Microscopic Structure And Performance Of Modified Bitumen

Modified asphalt with good performance has been widely used, as a kind of hybrid system, it is a polymer swelling in asphalt, so as to transfer the performance of the polymer in the asphalt, the difference of the macroscopic properties is the result of joint action of the microstructure such as phase state, shape, size and uniformity. Therefore, studying the microstructure of modified asphalt, revealing the relationship between microstructure and macro properties is already imperative.In this paper, based on previous studies, first of all, to investigate the preparation of process parameters on the impact of SBS modified asphalt technology indicators from two aspects of shear time, swelling time. Under the condition of prolonging shear time and swelling time, to reveal the connection of macro and micro performance parameters and to explore the description method of the microscopic characteristics of compatibility of modified asphalt. The results show:Softening point, viscosity, complex modulus of SBS modified asphalt gradually slowly rising trends by extending shear time. The numerical value after compatible keep stable, have smaller fluctuation margin, for jinling70#road asphalt, the compatibility of star-shaped SBS is a little better than linear SBS, and shear time of90min is recommended for both of them. The blending dispersion process of modified asphalt is a process of dynamic balance and it is continuing after modified asphalt getting compatibility; the microscopic parameters of modified asphalt have been under cyclical fluctuations, the cycle time shortens lately.The adding of swelling process makes softening point, viscosity, complex modulus of linear SBS modified asphalt increase under the same shear time, it is more likely to happen swelling relative to the star structure, swelling time of120min is recommended; for the star structure SBS, softening point increases significantly, viscosity and the complex modulus decrease.Modified asphalt has volatile performance before compatible, even achieve compatibility, it can be stable in the end. The area percentage and average area of modifier have less volatility after reaching compatible, the size distribution of polymer is more even, the distribution of the polymer modified asphalt is given priority to aggregate distribution; the ratio of the length of axis and its standard deviation present cyclical fluctuations in the process of shearing, and volatility is larger.Secondly the relationship between the macro and microscopic parameters of the modified asphalt performance is matched using regression analysis, the properties and microscopic morphology of two kinds of modified asphalt present a good relationship.For the correlation of regression equation, it is verificated by the grey system incidence degree in this paper, results show:macro performance and average area, area percentage of Star-shaped SBS modified asphalt have better relevance and correlation, the relevance and correlation of macro performance and the ratio of he length of shaft、the standard deviation of the ratio of he length of shaft is superior to the average area, area percentage. The whole fit of the macro and micro parameters of Star-shaped SBS modified asphalt is better than that of linear SBS modified asphalt.