Study on the influence of thermal oxidative aging temperature on the properties of polymer modified asphalt
Different mixing temperatures can lead to different initial aging states of asphalt,which may affect the long-term aging degree of asphalt and the service life of pavement.In order to compensate for the lack of existing research on the correlation between short-term aging temperature and long-term aging degree,the modified asphalt with different SBS contents(SBS accounted for 3.0%,4.0%,and 4.8%of the total mass of modified asphalt,respectively)was prepared in this paper.The thermal oxidative aging temperature that covered three mixing techniques to perform short-term aging on modified asphalt was selected,and the long-term aging tests on modified asphalt with different degrees of short-term aging for different periods of time were conducted.60℃dynamic viscosity test,dynamic shear test,and infrared quantitative analysis test on SBS modified asphalt with different degrees of aging were conducted,and the influence of mixing temperature on the macroscopic and microscopic properties of asphalt at various stages of long-term aging was analyzed.The research results showed that,(1)Within the experimental time range,the aging degree of modified asphalt characterized by dynamic viscosity at 60℃showed a pattern of low-temperature mixing＜medium-temperature mixing＜high-temperature mixing,and the longer the pressure aging time,the greater the difference in aging degree.(2)When using the 60℃rutting factor as the evaluation index for aging degree,the aging degree of low-temperature mixed asphalt was lower than that of medium-temperature mixed asphalt in the early stage,and as time went on,the aging degree gradually approached that of medium-temperature mixed asphalt.But the aging degree of both had always been lower than that of high-temperature mixed asphalt,and over time,the gap between them gradually widened.(3)When the mixing temperature reached 183℃,the degree of asphalt aging increased sharply,and as the pressure aging time prolonged,the growth trend of aging degree increased.In practical engineering,the mixing temperature should be controlled as much as possible not to exceed 183℃.(4)The carbonyl index and sulfoxide index of modified asphalt both increased with the prolongation of aging time,but the growth rate of carbonyl index gradually decreased,while the growth rate of sulfoxide index remained high.
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维普
