Study On Preparation And Properties Of Ultra-thin Wearing Layer High Viscosity And Elasticity Recovery Modified Asphalt

Cement concrete pavement occupies a significant position in highway,but with the increase of traffic volume and traffic load year by year,the function of pavement will be reduced,resulting in traffic jam,affecting traffic safety.In order to improve the service life of the pavement,reduce the maintenance cycle and reduce the maintenance cost,it is a good idea to overlay the asphalt ultra-thin wearing layer on the old cement pavement.However,40%of the structural stability of ultra-thin wearing layer depends on asphalt binder,thus,it is essential to develop new asphalt binder.In this paper,a kind of modified asphalt with high viscosity and elasticity recovery used for cement concrete pavement in "white change black" project was prepared.Firstly the types and dosage range of modifiers were preliminarily determined by tests.Secondly,the comprehensive performance analysis and evaluation of the modified asphalt were carried out by the three indexes,elastie reeovery,dynanic viscosity and adhesion test.The formula of the modified asphalt with high viscosity and elasticity recovery was determined.Finally,the performance of the self-made modified asphalt with high viscosity and elasticity recovery was explored through the comparative test,and the pavement performance of the ultra-thin wearing layer of the modified asphalt with high viscosity and elasticity recovery was verified,including dynamic shear rheometer test,bending beam rheometer test,creep test,rutting test,low temperature trabecular bending test,immersion Marshall test,freeze-thaw splitting test,etc.The main research results are as follows:(1)Preliminary tests confirmed that the modifiers were SBS,natural asphalt N1,compatibilizer Z1 and rubber powder,and the corresponding content ranged from 3.5%to 5%,5%to 10%,0.6%to 1.1%and 10%to 15%,respectively.(2)When the content of SBS,natural asphalt N1,compatibilizer Z1,rubber powder and stabilizer was 5%,7.5%,1.1%,15%and 0.3%respectively,the performance of high viscosity and elasticity recovery modified asphalt was the best.(3)The adhesive grade of self-made high viscosity and elasticity recovery modified asphalt to aggregate was grade 5.Even after freezing and thawing,the shear strength and peeling strength were 2.3 MPa and 1.9 MPa,respectively.(4)The dynamic viscosity of self-made high viscosity and elasticity recovery modified asphalt at 60℃ and the elastic recovery performance were very considerable;the rutting factor of self-made high viscosity and elasticity recovery modified asphalt was always the largest,and its rutting resistance was the strongest;when the temperature was-18℃ the creep stiffness(S)and creep rate(m)of the specimens were ranked as follows:sample 3<sample l<self-made<sample 2,sample 3>self-made>sample l>sample 2,respectively.(5)The high temperature performance,low temperature performance and water stability of the self-made high viscosity and elasticity recovery modified asphalt mixture could meet the requirements of the specification.