| Compared with other modified asphalts,crumb rubber asphalt has higher and lower temperature performance.lt is also one of the effective ways to reduce used tires,which is not only beneficial to environmental protection,but also saves resources.At the same time,the cost is much cheaper than other modified asphaltWith the process of the rubber powder by microwave activation,the performance of the crumb rubber modified asphalt can further improveand.In addition,the shortcomings of separation and high viscosity can be overcome.lt is proved by many researchers that the microwave activation is a simple and economical treatment method.However,both the performance of microwave crumb rubber modified asphalt(MCRMA)after aging and the mechanism of action between asphalt and rubber powder after aging are not fully understood,which greatly limits the promotion and application of MCRMA.Therefore,the aging characteristics and the mechanismof MCRMA are deeply studied,which is help for improving the quality of MCRMA and the service life of asphalt pavement.In this paper,the activated crumb rubber asphalt was prepared by origin asphalt and crumb rubber by microwave activation.Then,the activated crumb rubber asphalt was aging by TFOT.The performance of modified asphalt after aging was tested by consistency tests and DSR test,in order to research the effect of any two aging factors on the performance of modified asphalt.The results show that both aging time and aging temperature will affect the performance of asphalt,but the degree of impact is different.According to the results analysis,it is considered that the effect of aging time as per 5h at 163OC equivalent about 2.6 to 3.6 times to the aging temperature as per 10? on the performance of the modified asphalt.Linear analysis found that the softening point index has a higher regression coefficient with aging time and aging temperature.Therefore,the softening point is used as the aging kinetic equation parameter of the activated crumb rubber asphalt.The aging kinetic equation is derived from the experimental data and formula,which is apply to the activated crumb rubber asphalt.Consistency tests,viscosity test and DSR test were used to analyze the aging characteristics of basic asphalt,ordinary crumb rubber asphalt and activated crumb rubber asphalt after short-term aging and long-term aging.The results show that the asphalt becomes brittle and hard after aging.In addition,the penetration and ductility values decrease as the aging temperature and time,while the softening point increases.The reason might be the loss of light components in the asphalt,increasing the resistance of molecule in asphalt,while results the viscosity value increasing rapidly.As the degree of aging deepens,the complex shear modulus and rutting factor of asphalt gradually increase,while the phase angle decreases.The results indicated that aging make the elastic component in the asphalt increases while the viscous component decreases,which deteriorates the high temperature deformation resistance of the asphalt.Additionaly,the anti-aging properties of activated crumb rubber asphalt are significantly improved compared to basic asphalt and ordinary crumb rubber asphalt.Finally,the aging mechanism of activated crumb rubber asphalt was analyzed by infrared spectroscopy,scanning electron microscopy and atomic force microscopy.It was verified that the activated crumb rubber had a significant improvement on the anti-aging performance of crumb rubber asphalt. |
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