Study On The Hot In-place Recycling Technology Of SBS-Modified Asphalt Pavement

In recent years, with the rapid development of highway construction, some sections have been revised into the large and medium stage. In order to take full advantage of waste and effectively save investment, the asphalt pavement recycling technologies were paid more and more attention. Asphalt pavement recycling technology has been successfully applied in China. The more and more high-grade road pavement structure used excellent performance of SMA modified asphalt mixture at present. Compared with the base asphalt, the studies on modified asphalt recycling technology appeared serious lag. Many modified asphalt pavement recycling still used the recycling technology of base asphalt, it was extremely unreasonable. Relying on thermal regeneration of the local highway projects, through the research on the laboratory experiments of SMA modified asphalt mixture recycling technology, the suitable method of asphalt pavement recycling was found.Through the systemic summary of extracting the shortcomings of the existing asphalt recycling method, the main performance factors of recycled asphalt were found, the applicability of current methods to the modified asphalt recycling was studied in this article. Through the comprehensive improvement of the existing test methods, finally, the representative samples of asphalt was got which can truly reflect the performance of asphalt of the original mixture.In order to further explore the mechanism of asphalt aging and recycling, through comparing the chemical composition and physical properties of the change of pre and post aging of asphalt, the aging mechanism of modified asphalt was described in depth; starting from the components regulation theory and consistency theory, the modified asphalt recycling theory was proposed. The impaction between traditional recycling agent and modifier was evaluated by asphalt test index, and the feasibility of modified asphalt re-modification was assessed.According to the characteristics of the regeneration of SMA mixture, compound of lignin fibers aging was evaluated, analyzed the reasons that led to fibers aging, the concept of fiber "short-term aging" and "long-term aging" were proposed. By comparing the performance changes of different "regeneration agent+fiber" mixture, the interaction was obtained between recycling agent and fiber, specific measures and techniques were given to reinforce the mixture in recycling. Finally, by means of laboratory tests, the feasibility of recycling modified asphalt has been demonstrated, and effect of modified asphalt recycling was evaluated. By comparing the road performance indicators of two recycled asphalt SMA mixture (not adjusted gradation and adjusted gradation), the importance of adjusted gradation was highlighted during SMA mixture regeneration.