Research On The Uniformity Of Asphalt Mixture Paving With Spiral Cloth Based On Discrete Element

The uniformity of the asphalt pavement is the guarantee for the good road performance and long life of the asphalt pavement.The complicated force system and movement system in the process of spreading asphalt mixture under the action of the paver spiral distributor cause the mixture to gradate and segregate,which affects the uniformity of paving.Therefore,it is necessary to further analyze and study the different dynamic states and paving characteristics of graded aggregates in the paving process.In this paper,by studying the conveying mechanism of the auger,the force and movement model of the asphalt mixture is established;with the help of discrete element EDEM software,the distribution law of the asphalt mixture particles after being transported and spread along the auger is analyzed,and the segregation in the process of the auger is studied.Causes and influencing factors,establish an evaluation method for paving asphalt mixture,carry out engineering surveys with the help of the Yunnan Provincial Department of Communications project,and carry out the uniformity inspection of the paving asphalt mixture.The main research work is as follows:(1)Explain the structural composition of the paver spiral distributor and the composition structure and mechanical characteristics of the asphalt mixture,and establish the mechanical function and motion function equations of the asphalt mixture particles,and study the spiral distribution of the asphalt mixture in the spiral distribution trough.The force and movement under the action of the device.(2)Analyze the discrete contact model between particles,between particles and geometric models,and carry out the simulation of paving asphalt mixture pavement by the spiral distributor of the paver,and establish the main structure and working parameters of the paver based on the actual project.The three-dimensional solid geometric model of the paving mixture conveyed by the auger of the paver.(3)Determine the value of the dispersion coefficient Sc of the asphalt mixture pavement section as the evaluation index of the uniformity of spiral cloth paving,and conduct single-factor simulation analysis and orthogonal simulation analysis to obtain a screw diameter of 420 mm,a pitch of 280 mm,When the material level coefficient is 1,the uniformity of the paving asphalt pavement is the best.The range analysis method is used to analyze,and the order of significant influence on the paving uniformity is obtained:screw diameter> pitch> material level coefficient.(4)Based on the four-side static moment theory of image particles,relying on the physical engineering to analyze and calculate the images collected by paving the AC-25 gradation type asphalt mixture,the uniformity evaluation index is given: the bin-weighted four-side static moment separation coefficient Cv Analyze the uniformity evaluation results of the asphalt pavement.According to the uniformity evaluation results,the uniformity changes of the asphalt pavement in different pavement sections in the transverse direction are verified.The uniformity of the asphalt pavement near the feed inlet of the auger is better.The uniformity of the middle section is the best,and the uniformity at the discharge port is poor.The measured uniformity of the auger paving asphalt pavement in the transverse direction and the asphalt mixture pavement obtained by the simulation analysis are in the transverse direction.The uniformity change law of the above has a good consistency.The study on the uniformity of asphalt mixture paving with spiral cloth based on discrete element is the anti-segregation design of the spiral distributor of the paver and has important research significance for improving the paving quality of the road surface.