Study On Preparation And Performance Of Wood Tar-based Rejuvenated Asphalt

The advantages of asphalt pavement are excellent driving experience,easy to repair,but lack of durability,easy to aging and damage defects.The aged pavement materials will produce a large amount of waste asphalt after milling.The reasonable and effective use of waste aged asphalt can save oil asphalt resources and reduce energy consumption.There is rich bamboo resources in the world,and bamboo production of China ranks first.In this thesis,environmentally friendly and widely sourced bamboo pyrolysis wood tar is used as the main part of rejuvenator of aging asphalt,and other additives such as biomass fiber are added to prepare composite rejuvenator.The RA-102 rejuvenator is used as the control group to rejuvenate aged 70#base asphalt and SBS modified asphalt.Combined with physical properties,rheological properties,chemical properties and microscopic properties,the performance and rejuvenation mechanism of asphalt binder(mixture)of wood tar-based rejuvenator were explored.The main conclusions of the study are as follows,(1)The proportion of each additive of wood tar-based rejuvenator in the quality of aged asphalt was obtained by orthogonal test as follows:15%wood tar,0.3%biomass fiber,5%plasticizer,0.3%compatibilizer,and 1%stabilizer.(2)Compared with RA-102 rejuvenated asphalt,wood tar-based rejuvenated asphalt has better thermal storage stability.Wood tar-based rejuvenator phase is not easy to separate from asphalt phase.Under the premise of uniform mixing,wood tar-based rejuvenated asphalt has longer storage time and more stable performance.(3)The test results of physical and rheological properties show that wood tar-based rejuvenator can significantly improve the low-temperature ductility and crack resistance of aged asphalt,but it will slightly reduce the high-temperature deformation resistance of aged asphalt.Due to the reinforcement effect of biomass fiber,the high-temperature deformation resistance of wood tar-based rejuvenated asphalt is slightly better than that of RA-102 rejuvenated asphalt.(4)The results of component analysis showed that after mixing of aged asphalt and wood tar-based rejuvenator,the contents of saturates and aromatics increased,and the contents of resins and asphaltenes decreased.The rejuvenator could dissolve the asphaltenes,and supplement the light components to restore the performance of aged asphalt.The infrared spectrum test results show that the strength of S=O bond and C=O bond is weakened after asphalt rejuvenation.For rejuvenated SBS modified asphalt,the C=C bond of butadiene is slightly enhanced.The wood tar-based rejuvenator can react with SBS modifier and repair the network structure of modifier.(5)The test results of microscopic properties showed that wood tar-based rejuvenator could promote the decomposition of bee structure of aged asphalt,reduce the area proportion of bee structure,increase the content of dispersed phase and continuous phase,reduce the roughness of asphalt surface,and better restore the surface morphology of aged asphalt.(6)The test results of road performance of AC-13 asphalt mixture show that the synergistic effect of wood tar and biomass fiber can significantly improve the strength and toughness of rejuvenated asphalt mixture,and prolong its service life while improving the performance of asphalt pavement.Compared with RA-102 rejuvenated asphalt mixture,wood tar-based rejuvenated asphalt mixture has good high-temperature stability,low-temperature crack resistance,water stability and aging resistance.Studying the internal mechanism of wood tar on the performance recovery of aging asphalt has an important guiding role in realizing the recycling and harmless treatment of agricultural and forestry waste,and further improving the recycling technology of waste asphalt resources in China.