The Research On The Optimized Design And Application Of AC-13, AC-20 Asphalt Mixture Gradation

Each kind of early disease and various structures lever asphalt mixture gradationis not designed properly which appears in our country's first-class highway asphaltpavement. Both of them have close relationship. The remarkable deficiency in therecommendation gradation of present standard in our country is the scope of gradationis too wide. Because our country is vast territory, and the great difference in variousregional climate condition and the transportation environment, the standard as anational wide technical guidance and the control standard must extend to every detail.It brings great difficulty to the design of mixture in each project. The realistic questionthat the general engineer's and technicians faced is how to chose the most suitabledesign gradation scope that apply to each project in a wide scope of gradation.This article focused on the typical aggregate of the up layer and the middle(down) layer, which is used in Foshan asphalt pavement. 4.75mm as the boundary ofthe fine and coarse aggregate, it will carry on the graduation combination ram densityexperiment, using the gap of coarse aggregate which is obtained from the experimentas a appraisal target. Then analysis the relation between the content of various particlesizes in the coarse aggregate and the coarse aggregate's gap rate. And then on thisbase, using the closest heap as the principle to decide the gradation scope of coarseaggregate. The principle of the fine aggregate is filling and does not interference withcoarse aggregate structure. It unify the Superpave's design thought and 4% ofdesign's percentage of gap rate determination then combine with the coarse aggregateto calculate the total rate of volume of fine aggregate. The mutual proportion of fineaggregate will use distribution; its gradation scope will unify the constructiontechnology standard to allow the undulation scope which is determined. From thisobtains aggregate gradation scope and the optimized design of the rate of gradation ofAC-13,AC-20 asphalt mixture. Though the synthesis appraisal among the volumetarget and the high temperature stability and the water stability to choose the bestgrading curve. This design method is difference from other popular design methodsamong the domestic and the foreign counties, the design achievement according tothis method is suited to the climate and transportation characteristic of asphaltpavement in Foshan area, is worth using and referring.