Study On The Properties Of Warm Mix Matrix Asphalt Based On The Effect Of Thermal Oxygen Aging

Asphalt mixture pavement is widely used in modern road construction for its excellent road performance.At present,hot asphalt mixture is used on the most asphalt pavements in China.Hot asphalt mixture not only consumes energy but also pollutes the environment,the warm mix asphalt mixture technology can reduce the temperature of mixing and construction of asphalt mixture,and alleviate energy consumption and environmental pollution.The aging of road asphalt is an important factor that affects the road performance and durability of asphalt pavement.The distribution of asphalt microstructure and molecular structure will affect the macroscopic performance of asphalt.Domestic research on warm mix asphalt is mainly based on macroscopic studies,and there is less research on microscopic propertie and long-term aging of warm mix asphalt.In this paper,macroscopic road performance and microscopic properties of matrix asphalt and warm mix asphalt subjected to thermal aging are studied.In this article 90 # maxtric asphalt,and two kinds of warm mixing agent was used as the test material,which adopts thin film oven to simulate short-term aging during asphalt mix and construction process,and uses pressure aging container test to simulate long-term aging during service under different aging conditions.The asphalt materials were subjected to penetration test,softening point test,ductility test,Brookfield rotational viscosity test,bending beam rheological test,and atomic force microscope test to study the effects of warm mix agent and aging on the road performance of the mixture asphalt.and provide test basis for the promotion and use of warm agent.Analyzing the high-temperature and low-temperature performance of warm mix asphalt through three indicators,analyzing the anti-aging performance of warm mix asphalt by the ratio of residual penetration ratio,residual ductility ratio,softening point increase rate,and the viscosity ratio before and after aging,analyzing the temperature-sensitive performance of warm mix asphalt by penetration index,penetration viscosity index and viscosity-temperature curve.The results show that the Evo warm agent can slightly improve the high temperature performance of the matrix asphalt,Evo warm agent can improve the low temperature performance of the matrix asphalt,and increase the temperature sensitivity of the matrix asphalt,improve the anti-aging properties of the matrix asphalt.USP warm agent reduces the high temperature performance of the matrix asphalt,improves the low temperature performance of the matrix asphalt,increases the temperature sensitivity of the matrix asphalt,and improves the aging resistance of the matrix asphalt in the short-term aging stage.The rheological tests of curved beams showed that Evo warm agent can improve the low temperature performance of the matrix asphalt under different aging conditions,and the best effect is obtained when the dosage of the warm agent is 0.6%.USP can also improve the low temperature performance of the matrix asphalt under different agingconditions.The effect is better than the Evo warm agent,and the higher the dosage is,the better the effect is.With Burgers parameter fitting,it can be seen that the two kinds of warm agents increase the dissipating energy of the matrix asphalt before and after aging,reduce the storage energy,and increase the dissipative energy ratio,which improves the stress relaxation ability of the matrix and enhances the crack resistance of the matrix asphalt.Atomic force microscopy(AFM)tests show that both the Evo warming agent and the USP warming agent change the microstructure of the matrix asphalt and only the matrix asphalt and the Evo warm asphalt exhibite obvious bee-like structure and phase structure.With the degree of aging deepens,the amount of matrix bitumen structures and the roughness becomes smaller and the surface bearing capacity becomes greater.The number of Evo warm mix bitumen structures,the area of the dispersed phase and the roughness increase.The bearing capacity of the surface becomes larger and the USP warm asphalt gradually becomes black and white with the aging deepens.