Curve Analysis And Pavement Performance Study On Step Interlock Gradation

The research shows that the pavement of embedded and squeezed dense asphalt mixture is superior to the traditional asphalt pavement in the aspects of high and low temperature,water stability,wear resistance,skid resistance and fatigue resistance.The structure is characterized by the formation of the skeleton structure between the coarse aggregates and the gaps between the skeleton structures are filled with bitumen,mineral powder and fine aggregate,thus forming a skeleton dense structure.The purpose of this paper is to analyze the gradation of asphalt mixture by progressive extrusion.With reference to the study of the skeleton structure of continuous gradation coarse aggregate at home and abroad,combined with the theory of step by step filling,the grade of mineral aggregate is filled with a step by step test,and the first order particle size aggregate is filled to the mixture of the previous grades particle size aggregates,and the density and bearing ratio are used as the evaluation index of the density of the aggregate skeleton.A new parameter index LE_n-1 value?n is used to be used to fill the aggregate size grade?is proposed for each grade filling test,and the influence of the change of its value on the mixed aggregate density and the bearing ratio results is studied,and the range of the value of the corresponding parameter LE_n-1 value is obtained by analyzing the filling results.In this paper,LE_n-1 was defined as the ratio of control particle size to effective particle size in aggregate mixtures with filler added.After consulting a large number of literatures,particle size with 60%passing rate was taken as control particle size and 10%as effective particle size.Compared with coarse aggregate,a step by step filling method is used for fine aggregate,and LE'_n-1 value is used to study the influence of the particle size on the density of the fine aggregate,and the range of the value of the corresponding filling grade is given.Appropriate composing proportion of coarse and fine aggregate was selected from filling test result,passing rate of 4.75mm was set as 35%and 25%to design aggregate gradation.At the same time,asphalt mixture gradation design was conducted with filler binder ratio of 1?1.2?1.4 and marshall specimens were molded,Also,indoor experiments were conducted to study merits and demerits of mixture pavement performance and the impact of filler binder ratio on it under various reference index LE values of coarse and fine aggregates.The advantages and disadvantages of pavement performance concerning different asphalt mixtures was evaluated using the results of rutting test,uniaxial penetration test,low temperature bending test and retained Marshall test,which demonstrate the reasonability of index range given above.In addition,the impact of filler binder ratio and mixture type on pavement performance were explored and filler binder ratio of 1?1.2 in the process of proportion design was recommended.