Dynamic Analysis Of Asphalt Mixture Spreading And Its Influence On Spreading Uniformity

Nowadays,the asphalt paving is affected by mechanical factors,material factors and human factors.The paving uniformity may not meet the requirements,which will affect the paving quality and service life of the pavement.Since the auger in the paver is easy to isolate the mixture during the paving process of the asphalt mixture,it is necessary to carry out the dynamic analysis of the spiral paving field of the asphalt mixture and the factors affecting the paving uniformity.And the control method is discussed.Therefore,this paper takes the paver auger as the research object,and through the theoretical analysis and simulation test and engineering test and verification research methods,the auger of different structural parameters and operating parameters is studied for the paving field.The impact and research on the factors affecting the paving uniformity of asphalt mixture and the control methods are carried out.The main research results are as follows:(1)Analyzed the main structure and working principle of the paver.For the auger of the asphalt mixture paver,according to the asphalt mixture,the Hooke elastic theory and the Newton viscous fluid dual properties and the force characteristics of the pellets,The type of movement of the asphalt mixture in the spreader auger was determined.(2)According to the basic equation theory of fluid motion,the RNG model and the Euler model are used to numerically simulate the mathematical model of fluid motion and the "domain" of the spiral transport field.For the auger field,a geometric model was created using CATIA,and a tetrahedral mesh of the motion field geometry model was obtained using ICEM CFD software.Set the material parameters and the motion field parameters of the asphalt mixture AC-20 in the CFX-Pre,set the solution control parameters,and solve the calculation domain of the asphalt mixture motion field.(3)According to the velocity vector diagram,velocity cloud map,time-average velocity graph and turbulent flow energy cloud diagram of the auger moving field,the velocity vector distribution,velocity cloud map distribution and time-average velocity distribution of the asphalt mixture in the auger moving field And the variation of the turbulent flow energy distribution in the auger was analyzed,and the specific influences of different pitch,screw diameter,rotation speed and feed amount on the motion field were obtained,and the pitch,screw diameter,rotation speed and feed amount were determined.The right value.According to the temperature cloud map of the auger moving field,the influence of different paving temperatures on the moving field temperature is analyzed by calculating the temperature change rate per unit area,and the loss of the moving field temperature at different initial temperatures is determined.(4)Based on the digital image processing technology and the Lambertian model,using MATLAB to perform the three-dimensional reconstruction of the two-dimensional surface of the image after the image is removed,decolored and grayscaled,the depth of the asphalt pavement is obtained.average value.According to the project,the uniformity analysis of the collected images was carried out.The results showed that the pitch of the paving was 280 mm,the structural parameters of the screw diameter of 420 mm and the working parameters of the rotational speed of 40r/min,paving the asphalt mixture.The ratio of TD/TDD of the road surface is 0.0831,which is less than 1.16 of the evaluation standard of the separation,and the paved road surface is uniform.(5)Based on the analysis of the separation of asphalt mixture,the influencing factors such as the preparation,transportation and unloading,paving and rolling of asphalt mixture were studied.In order to improve the uniformity of paving,the structural parameters and working parameters of the spreader auger were reasonably selected.Based on the construction process of the paver,the joint operation control method of the construction machine group was proposed.Moreover,the auxiliary mechanism of the asphalt mixture paver is designed to further improve the paving uniformity of the asphalt mixture.