热再生沥青混合料微波加热自愈性能研究OA

[Purposes]Under the constraints of environment and resources,reclaimed asphalt pavement(RAP)is widely used in numerous reconstruction and extension recycling projects.However,compared with traditional newly-paved asphalt pavement,the recycled pavement is more prone to cracking hazards,and its long-term service performance is affected.In view of the problems that hot recycled asphalt pavement is prone to cracking,and its self-healing behavior remains unclear,this study aims to quantitatively investigate the self-healing performance of its cracking damage by introducing microwave heating technology to clarify the key influencing factors and mechanisms and provide a technical basis for improving the durability of recycled pavement.[Methods]Three recycled asphalt mixture groups and one newly-mixed base asphalt mixture group were designed.The effects of microwave heating duration,mixing time,and aging degree of aged materials on the self-healing performance of recycled asphalt mixture were systematically analyzed,and the self-healing results were compared with those of the traditional newly-mixed base asphalt mixture group.[Results]Although the recycled asphalt mixture possesses self-healing ability,a longer microwave heating duration and a higher healing temperature are required to achieve a self-healing rate similar to that of the new mixture.Meanwhile,the blending degree of old and new asphalts and the aging attributes of the aged asphalt also significantly affect the self-healing behavior.Under short-term microwave action,if the blending is insufficient,or the aging degree of the incorporated aged materials is more severe,the self-healing process mainly relies on the softer base asphalt part,which is activated and softened under microwave heating to exert a good healing effect.However,under long-term microwave heating,both the aged and base asphalts are fully softened,and the self-healing rates of the three recycled groups are 80%-91%,approaching the level of the newly-mixed group,but attention must be paid to the risk of localized asphalt softening and loosening.[Conclusions]Microwave heating technology effectively promotes the crack healing of recycled asphalt pavement,but its self-healing behavior is jointly influenced by the blending degree of old and new asphalt,the attributes of aged asphalt,and the microwave heating duration.In practical applications,the microwave heating duration should be reasonably selected to balance its self-healing effect and the risk of loosening and bulging.