Study On Preparation,property Characterization And Modification Mechanism Of Vulcanized Eucommia Ulmoides Gum Modified Asphalt

Asphalt pavement is widely used in various grades of roads due to its good driving comfort,convenient maintenance and excellent road performance.In recent years,research on rubber modified asphalt has increased,and the modified asphalt has good performance.As a kind of rubber,natural eucommia ulmoides gum(EUG)has a wide range of sources and is naturally renewable.Studies have found that EUG can be used to improve the road performance of asphalt and its mixtures.However,the current research is mainly focused on using conventional test methods to study the basic properties of common EUG modified asphalt and its mixture,there are few researches on the preparation method of vulcanized EUG modified asphalt,its high-temperature stability,low-temperature crack resistance,thermal stability,etc.,and few studies on its modification mechanism.Therefore,this article proposes a preparation method of modified asphalt with vulcanized EUG to study the microscopic appearance and dispersion of modified asphalt;molecular changes,structural composition,quality changes,volatile components and their effects on road performance when heated.In addition,the changes of microstructure and mechanical properties of modified asphalt caused by the addition of vulcanized EUG and the self aging of asphalt are analyzed,and the effect of vulcanized EUG on the road performance of asphalt mixture is studied,which enriches the asphalt modification technology,improve the durability of asphalt pavement.First,vulcanized EUG modified asphalt was prepared,and its road performance,rheology performance,chemical composition,phase structure,micro morphology were studied by three index tests,dynamic shear rheometer,curved beam rheometer,Fourier infrared spectroscopy,X-ray diffraction and environmental scanning electron microscopy.It was found that the low-temperature ductility of modified asphalt is improved obviously,and the softening point is not much different.As the content of vulcanized EUG increases,the penetration becomes larger,the elastic recovery slowly increases,and the Brookfield viscosity remains almost unchanged.The addition of vulcanized EUG improves the high-temperature rutting resistance and low-temperature crack resistance of the modified asphalt,but it slightly reduces the fatigue crack resistance of the asphalt.The modified asphalt of vulcanized EUG is mainly a physical blending process,meantime,there is a slight chemical reaction.After the asphalt is modified by vulcanized EUG,new diffraction peaks appear on the X-ray diffraction pattern due to the presence of zinc oxide,and when the content of vulcanized EUG is 10%,the compatibility of the two is better.The swelling effect of vulcanized EUG has resulted in uneven asphalt surface and many pits.As the content of vulcanized EUG increases,desulfurization and degradation reactions will occur,improving its compatibility with asphalt.Secondly,differential scanning calorimetry,thermogravimetric analysis-infrared combined technique and dynamic thermodynamic analysis methods were used to study the road performance of vulcanized EUG modified asphalt from the perspective of thermal analysis.The research results showed that after the matrix asphalt is modified by vulcanized EUG,the compatibility between the two is better,the thermal stability of the modified asphalt is improved,the glass transition temperature is lowered,and the low-temperature crack resistance is enhanced.However,the effect of improving thermal decomposition stability is not obvious.The addition of vulcanized EUG reduces the production of toxic gas products during the construction of the asphalt pavement and when a fire occurs on the asphalt pavement.It is recommended to use 10%vulcanized EUG to modify the asphalt.Then,the modified asphalt of vulcanized EUG with the best content(10%)was tested by atomic force microscope to study the influence of the blending of vulcanized EUG and the self-aging of the asphalt on the microstructure and mechanical properties of the modified asphalt.The results showed that due to the incorporation of vulcanized EUG in the modified asphalt,the number of "bee-like" structures is greatly reduced,and the volume is reduced,and the microstructure of modified asphalt after aging changes less obviously than that of matrix asphalt.The roughness index of modified asphalt before and after aging is smaller than that of matrix asphalt under the same conditions,and the growth rate is smaller than that of matrix asphalt.The incorporation of vulcanized EUG and the aging of the asphalt will decrease the adhesion value and energy dissipation value,and increase the Young’s modulus in the modified asphalt,and the decreasing or increasing trend is less than that matrix asphalt.According to the test results of the microstructure and mechanical properties of AFM,the incorporation of vulcanized EUG can improve the anti-aging performance of asphalt.Finally,the influence of vulcanized EUG on the road performance of asphalt mixture was studied by using rutting test,low temperature trabecular bending test,immersion Marshall test,freeze-thaw splitting test.Studies have found that the addition of vulcanized EUG is beneficial to improve the high temperature stability,low temperature crack resistance and water stability of the modified asphalt mixture,and meet the actual use of asphalt pavement requirements.In a word,this paper proposes the preparation method of vulcanized EUG modified asphalt,reveals the influence law and modification mechanism of vulcanized EUG on asphalt road performance,enriches the asphalt modification technology,and expands the application range and utilization rate of EUG,improve the durability and service level of asphalt pavement.