Performance Comparison Of UTA Ultra-thin Overlays Modified By High Viscosity Direct Feed

This preventive maintenance technology of ultra-thin cover has attracted much attention because of its fast construction speed,low operation cost and good maintenance effect.However,the research and application of ultra-thin cover are few in China,and there are still many problems to be solved.Therefore,this paper relies on the foundation project of Chongqing Jiaotong University ultra thin cover(UTA)application technology research.The main research contents include the following aspects:Firstly,the high viscosity asphalt and high viscosity SBS modified asphalt were prepared by adding different amount of high viscosity direct feed into the base asphalt and SBS modified asphalt according to the specific modification process,and the penetration,softening point,ductility,short-term aging,135℃ Brinell viscosity and segregation tests were carried out for 8 kinds of different blended asphalt.The experimental results show that the addition of high viscosity direct feed can reduce the penetration of matrix asphalt binder,increase the softening point index of matrix asphalt,increase the impact on the ductility first and then decrease,and the best addition of high viscosity direct feed in matrix asphalt after adding high viscosity direct feed is 12.3%(internal).After short-term aging test,the penetration index of matrix asphalt increases first However,the softening point and ductility index of the base asphalt increase with the increase of the content of high viscosity direct feed,and the viscosity of the base asphalt increases by 396.8%under the optimum content of high viscosity direct feed.The addition of high viscosity direct feed will reduce the penetration index of SBS modified asphalt binder,and improve the softening point index and ductility index of SBS modified asphalt.After short-term aging test,the addition of high viscosity direct feed will have no effect on the penetration index of SBS modified asphalt.After short-term aging,the addition of high viscosity direct feed will improve the softening point and ductility value of SBS modified asphalt,and the addition of high viscosity direct feed will make SBS modified asphalt soften The viscosity value of SBS modified asphalt increases,but the viscosity is too high when the content is too high.The best content of SBS modified asphalt with high viscosity direct feed is 8%,and the viscosity value increases 43.2%when the content of high viscosity direct feed is 8%.The SBS modified asphalt binder is more stable by adding high viscosity direct feed.After adding high viscosity direct feed,the improvement rate of high temperature performance of matrix asphalt binder is higher than that of SBS modified asphalt.The increase rate of Brinell viscosity of high viscosity asphalt is higher than that of high viscosity SBS modified asphalt,but the value of Brinell viscosity is lower than that of high viscosity SBS modified asphalt.The best combination of asphalt binder data index is SBS modified asphalt+8%high viscosity direct feed.Secondly,uta-10 graded drainage asphalt mixture is used to verify its road performance.Through the relevant design specifications and relevant documents to determine the grading design and oil stone ratio of ultra-thin cover.The results show that the asphalt aggregate ratio is 4.7%,the 2.36mm pass ratio is 17%,and the void ratio is 14.6%.Finally,the high temperature stability,water stability(asphalt adhesion test,immersion stability test,freeze-thaw split test),Kentucky dispersion test and cherenberg leakage test,water permeability and skid resistance of asphalt mixture with different types,mixing processes and additives are studied to evaluate the adaptability of high viscosity direct feed to the mixture Performance.The experimental results show that the dispersion index,high temperature stability index and water stability index of high viscosity asphalt are significantly improved,the water permeability index and friction performance index are slightly improved,and the leakage analysis index has degradation effect.The dispersion index and high temperature stability index of high viscosity SBS modified asphalt are significantly improved,while the water stability index,water permeability index and friction performance index are slightly improved,and the leakage index is degraded.The best combination of uta-10 asphalt mixture data index is basalt coarse aggregate+SBS modified asphalt+high viscosity direct feed(dry mix).