Research on aging characteristics of recycled asphalt and its induced aging of new asphalt from hot in-plant recycled asphalt mixture
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Abstract:
In order to explore the aging process and mechanism of new asphalt in plant hot-mixed recycled asphalt mixture, the dynamic viscosity and partial road performance of the recycled asphalt, the mixture of new and old asphalt and the matrix asphalt after RTFOT aging and PAV aging were tested. The macroscopic performance attenuation law of the mixture of new and old asphalt during the aging process in thermal regeneration was compared and analyzed. After that, the aging process and mechanism of the mixture of new and old asphalt were explored by infrared spectroscopy and differential calorimetric analysis scanning. The results show that RTFOT aging and PAV aging make the viscosity of recycled asphalt rise significantly and the low temperature performance decline rapidly. After RTFOT aging and PAV aging, the change range of dynamic viscosity and low-temperature performance of the mixture of new and old asphalt is much higher than that of the matrix asphalt, which proves that the aging rate is faster than that of matrix asphalt. Meanwhile, microscopic analysis show that in addition to the independent aging of new asphalt and recycled asphalt, there is also a chemical effect between them, that is, some active groups in recycled asphalt have a more obvious promotion effect on the aging process of new asphalt, here called induced “aging”. This induced aging changes the aging mechanism of the matrix asphalt by changing the aging process of it.
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Supported by National Natural Science Foundation of China (51708072).
