Research On Gradation Design Method Of Drainage Asphalt Mixture Based On Void Characteristics

As a new type of road with excellent structure and strong functionality,the drainage asphalt pavement meets the requirements for road comfort and functionality.As the component material of drainage asphalt pavement,the large voids caused by the skeleton-void structure of drainage asphalt mixture provide pavement better drainage function.However,the strength of the internal structure of the mixture will be reduced by the oversize voids,which will affect the durability of the pavement.Therefore,the void characteristics are the key factors to balance the drainage function and pavement performance of drainage asphalt mixture.The gradation design of drainage asphalt mixture is carried out based on the void characteristics,so that the drainage asphalt mixture can not only meet the requirements of road performance,but also play a good drainage function.In this paper,the models of drainage asphalt mixture with different gradation were established,and the characteristic parameters of void were obtained to analyze the relationship between gradation and void characteristics.The influence of void characteristics on drainage function and road performance of drainage asphalt mixture was studied in order to build a comprehensive performance balance relationship.And the research on gradation design technology of drainage asphalt mixture based on void characteristics was carried out.Firstly,the void characteristics of drainage asphalt mixture were studied.The discrete element method was used to construct the virtual specimen model of drainage asphalt mixture.The formation of void micro-structure of drainage asphalt mixture was realized mainly by simulating the morphological characteristics of coarse aggregate and the characterization of mineral gradation,and dense “virtual” slice treatment was carried out to obtain the micro-characteristic parameters of void.Secondly,according to the relationship between the main sieve pass rate and the macro-attribute parameters of void and the micro-characteristic parameters of the void,the change rule of void characteristics of different mineral gradation was analyzed,and the influence of void characteristics of different mineral gradation on drainage function and road performance of drainage asphalt mixture was studied.Finally,for the gradation design of the drainage asphalt mixture,the comprehensive performance balance relationship of the drainage asphalt mixture was constructed based on the void characteristics to design the gradation range,and the optimum asphalt dosage was determined by the test of schellenberg binder drainage and kenterbaoge aggregate scattering.Through the laboratory performance test,the designed drainage asphalt mixture had good road performance.