Research On The Mechanism And The Pavement Performance Of SBS Modified Asphalt And Rubber Powder Modified Asphalt

SBS modified asphalt with good performance of high and low temperature is widely used in China, and rubber powder modified asphalt is a new kind of composite material which has the advantages of environmental protection, economy, energy saving, noise reduction and some other features. At present, there is no uniform recognition on the performance of two kinds of modified asphalt, and many controversies exist for a long time.The object of this paper is comparing the performance of SBS modified asphalt with that of rubber modified asphalt systematically. By changing the shear time, shear temperature and shear rate, the preparation process of SBS modified asphalt and rubber powder modified asphalt was studied comparatively. The reasonable preparation process of the two was also recommended according to their properties.High and low temperature properties, sensitive-temperature property and anti-aging property of SBS and rubber powder modified asphalt containing different amounts of modifier were comparatively studied by softening point test, ductility test, BBR test, penetration test, RTFOT and PAV tests. Then the reasonable amounts of modifier were proposed combined with the various performance indexes of modified asphalts.The aggregate gradation and optimum asphalt content of AC-13 and SMA-13 were determined. the high temperature stability, low temperature cracking resistance and water stability of different asphalt mixture were compared by rutting test, Hamburg wheel tracking test, Marshall stability test, freeze-thaw splitting test and low temperature bending test.To explore the mechanism of SBS and rubber powder modified asphalt, the fluorescent microscope and FTIR were selected to analyze the blending state of modifier and asphalt and the changes of asphalt molecular structure.The test results show that high temperature performance, low temperature performance, sensitive-temperature property and anti-aging resistance of SBS and rubber powder modified asphalt improve greatly with the increase of modifier content. High temperature performance of SBS modified asphalt is better than that of rubber powder modified asphalt,but the low temperature performance and sensitive-temperature property of rubber powder modified asphalt are better than those of SBS modified asphalt. The high temperature stability and water stability of SBS modified asphalt mixture are higher than that of rubber powder modified asphalt mixture when aggregate gradation is the same. Experimental results about the mechanism show that two kinds of modifier just blend with asphalt and there are no chemical reaction occurred.The investigation plan for pavement diseases was presented and the social and economic benefits, scope of application and existing problems of the two modified asphalt were also analyzed in last part of the paper. The research results can provide some guidance and reference for engineering practices of two kinds of modified asphalt.