Study On The Design Of Asphalt Mixture In Lanzhou Urban Road Based On The Status Of Simulating Dusty And Sprinkling State

As the main form of future road development in China,asphalt pavement has the advantages of smooth surface,good abrasion resistance,comfortable driving,convenient construction,simple maintenance,suitable for segmental maintenance and construction,etc.It is widely used in urban road construction.The main road surface of Lanzhou City is also dominated by asphalt pavement,but the sandstorms in Lanzhou area are frequent.Loess particles are easy to cover the surface of asphalt pavement,and the roads are frequently sprinkled,so the soil particles are integrated into the water to form mud,which spreads widely over the surface layer of asphalt pavement.It not only reduces the anti-sliding safety of the road surface,but also under the pumping action of the vehicle tire,the mud adhered to the road surface accelerates the stripping of the asphalt and the mineral material,reduces the stability of the asphalt mixture,and seriously affects the service life of the asphalt pavement.In view of the above problems,this topic takes Lanzhou urban road as the research object,compares and analyzes the water stability,slip resistance performance and fatigue resistance performance of common asphalt mixture and rubber modified asphalt mixture,and evaluates the adaptability of the two mixed materials in dusty watering state.It provides a reference for the choice of asphalt pavement type and material composition design of urban roads in Lanzhou.The main research contents are as follows:(1)Determine the type of raw materials and material technical indicators used in the research,select 40 mesh rubber powder to prepare rubber asphalt,and determine the best preparation process.(2)For the type of asphalt surface layer commonly used in urban roads in Lanzhou City,AC-13 was selected as the grading type studied in this paper,and the gradation composition design of common asphalt mixture and rubber asphalt mixture was carried out.(3)Simulate the actual environment of the road surface under dusty watering conditions,perform water stability analysis(immersion Marshall stability test,freeze-thaw splitting test,hydrodynamic scouring test),slip resistance analysis(Loss abrasion test)and fatigue resistance analysis(four-point bending fatigue test)to compare and evaluate mud-water stability,slip resistance and fatigue resistance oftwo asphalt mixtures.(4)Establish a finite element numerical model of pavement structure of two kinds of asphalt mixture,analyze the shear stress and vertical displacement of the surface layer of two types of pavement structures under vehicle load,and determine the load adaptability of the structure.The test results show that the mud-water stability,slip resistance and fatigue resistance of the rubber asphalt mixture are better than that of the common asphalt mixture.Before and after the hydrodynamic scouring test,the stability of the common asphalt mixture is reduced by 18.8%.However,the stability of the rubber asphalt mixture is only reduced by 7.58%.The finite element software simulation analysis shows that the shear stress of the surface layer of rubber asphalt pavement is greater than that of the surface layer of common asphalt pavement.The vertical displacement of the two asphalt mixtures is only 0.01 mm.The rubber asphalt mixture has better adaptability in the dusty watering state than the common asphalt mixture.