Abstract:Multiply recycling process for asphalt mixture was simulated by laboratory test, then the physical properties and component content of multiply recycled asphalt were investigated. The mix design of recycled asphalt mixture was determined by Marshall test, and the properties were evaluated by uniaxial penetration strength test, semi circular bending test and freeze thaw test. And the phase angle variation of recycled mixture under the synchronous coupling of temperature and loading frequency was analyzed by asphalt mixture performance tester(AMPT). The results show that after multiply recycling of asphalt, the rheological property changes adversely, high temperature property improves and low temperature property change much adversely. The compatibilization of rejuvenating agent in the aged asphalt enhances as its content increases, and decreases exponentially as recycling cycle increases. The rutting resistance of recycled mixture enhances logarithmically as recycling cycle increases, and the moisture susceptibility is less sensitive to recycling cycle, after the third recycling for asphalt mixture, the Marshall volume parameters can meet the specification requirements. The viscoelastic property of recycled mixture for first cycle is similar to virgin mixture, after the second recycling, the elastic effect is enhanced, and the low temperature anti cracking property reduces significantly. In summary, the multiply recycling for asphalt mixture should focus on its low temperature anti cracking resistance.
