Material Design And Performance Simulation Evaluation Of UTAC-10 Based On Discrete Element Method

Since the reform and opening up,China's highways and other infrastructure construction has developed rapidly,and the society's requirements for road safety and comfort have gradually increased.The asphalt surface layer directly bears the wheel load,which is easy to produce ruts,pits,structural wear and other diseases.The anti-sliding surface layer of the old road surface is an effective means to improve the road performance.At present,most of the highway maintenance adopts AC-type asphalt mixture,which has poor economic efficiency and is difficult to adapt to the trend of road maintenance in the future.UTAC-10(Ultra-thin Asphalt Concrete 10)is a typical high-performance anti-slip overlay material with excellent road performance and good economic efficiency.Compared with ordinary asphalt mixture,the technical design of the material is difficult,and the traditional material design method is difficult to meet the design requirements.In recent years,numerical simulation has been gradually applied to the microscopic scale research of asphalt mixture,which has become an effective means to deeply study the performance of asphalt mixture.Based on this,this paper based on discrete element method to carry out volume material design and performance simulation of UTAC-10,and improve asphalt mixture material design method,rich gradation,particle geometry and other factors to understand the influence of UTAC-10 road performance.Firstly,based on the three-dimensional structure light scanning technology,the coarse aggregate geometry is obtained.The three-dimensional angularity index is used to evaluate the aggregate angularity.The aggregate aggregate geometry is used to generate the coarse aggregate discrete element model,and the coarse aggregate model database is constructed.According to the principle of the volumetric method,coarse aggregates are assembled according to the grading,and a coarse skeleton model is generated.The “coincidence-deletion method” is used to fill the virtual asphalt mortar,and some of the mortar particles deleted according to the distribution of the void phase are used to simulate the void,and the discrete element simulation design of the asphalt mixture is realized.Secondly,the internal contact is analyzed based on the volume characteristics of the asphalt mixture,and the mesoscopic contact model between aggregate-aggregate,aggregatemortar,mortar-mortar is determined,and the Burgers parallel bond model suitable for asphalt mixture is developed.The conversion relationship between macroscopic test parameters and mesoscopic parameters is established.The values of the parameters of the mesoscopic contact model are determined according to the empirical values and research results in the existing research.The rationality of the parameter values is verified based on the indoor test results.Finally,based on PFC,the anti-sliding structure,volume characteristics and hightemperature performance simulation evaluation platform of asphalt mixture were developed.The influence of grading factors on UTAC-10 anti-slip structure and anti-sliding skeleton structure was investigated.The gradation and aggregate angularity were used.And the influence of needle-like content as the influencing factor,design single factor test and multi-factor orthogonal test,analyze the influence of various factors on the UTAC-10 skeleton clearance rate and triaxial shear strength.An asphalt mixture discrete element design platform including volume design,anti-sliding evaluation,volume characteristic analysis and high temperature performance evaluation was initially established.