Study On The Preparation Of Low-grade Modified Asphalt

In this paper, 30# and 50# low grade asphalt were used as the row materials, and the asphalts were modified with the using of SBS, rubber and rubber/SBS compound modifiers. In order to explore the preparation technology of low grade modified asphalt, three indicators(softening point, penetration, and ductility), film aging, Brookfield rotary viscometer and BBR were adopted to analysis the modified samples, afterwards, the economic technical analysis is used to determine the most appropriate way of producing low grade modified asphalt.The results of SBS modified asphalt experiments show that when the SBS dosage is within 0-6%, with the increasing of SBS’s content, the penetration gradually declines, softening point increases, so the high temperature properties of the modified asphalt were improved. And the anti-aging performance of modified asphalt and the high temperature ductility improved significantly. But SBS has little effect on the asphalt’s low temperature performance. And due to the high production cost of SBS modified asphalt, it is not recommended to use the process to produce low grade modified asphalt.The results of rubber modified asphalt experiments show that when the rubber content is within 10%-19%, rubber can significantly improve asphalt’s performance in both high and low temperatures and anti-aging properties. With the increasing of the rubber’s content, the relatively high temperature ductility decreases, while the viscosity of modified asphalt increases dramatically, making the mixing and compaction temperature very high. Despite its production cost is low, considering its adverse impact on the asphalt’s properties, it is not recommended to use the process to produce low grade modified asphalt either.Rubber/SBS compound modification can make the best use of their own advantages, SBS and rubber could work effectively with each other. Rubber/SBS compound modifier can improve asphalt’s high temperature performance, low temperature performance and anti-aging performance at the same time. In addition, rubber/SBS compound modified asphalt has moderate production and using cost. So it is recommended to use rubber/SBS compound modification to produce low grade modified asphalt.