Studies On Aging And Regernating Of Bitumen

With the freeway volumes and natural environment, property of flexible pavements deteriorates gradually owing to asphalt aging and aggregate finning and structure changing of asphalt pavement. Therefore, lots of pavements need to repair in large-scale even repave wholly after using a long time, which will bring large numbers of waste asphalt mixture. Therefore, it is important to regenerate the waste asphalt mixture in order to protect environment and economize resource. But one of the difficulties of recycling waste asphalt mixture is evaluating the characters of old asphalt, the other is producing excellent recycling agent according to the mechanism of the asphalt aging.This paper studied the influence of heat, oxygen and UV-light on chemical component and physical properties of asphalt through thin film oven test (TFOT), UV-irradiation test and long-time oxidation test. The results showed that changes of content of saturants, aromatics and asphaltenes were similar during the three kinds of aging test, i.e. the saturants content almost kept invariable, the aromatics content obviously decreased and the asphaltenes content remarkably increased. However, the change of resin content was different , it increased in long-time oxidation test but decreased in the other aging test.Based on the conclusion of aging test and the properties of the recovered asphalt, two kinds of recycling agents (named A and B respectively) were prepared in this paper. The property of the regenerated asphalt was investigated. The result indicated that the properties of regenerated asphalt added recycling agent B were better than that of regenerated asphalt added recycling agent A. The character of regenerated asphalt meet to criterion of road asphalt after 20wt% recycling agent was added. Meanwhile, the aging resistance of the regenerated asphalt was good.Using hot-in plant recycling, the influence of recycling agent on the property of regenerated asphalt mixture was investigated. The results showed that the volume properties and performance of resisting damage of moisture of regenerated asphalt mixture were improved by adding the recycling agent. Splitting test indicated the low temperature property was improved. Tests of Marshall stability and immersion Marshall about regenerated asphalt mixture indicated the technical parameters ofregenerated asphalt mixture met to the standard of hot-mixed asphalt mixture while the content of waste asphalt mixture was 20wt% and 30wt% respectively...