Study On The Gradation Features And Structure Indexes Of Stone Matrix Asphalt

Since SMA was introduced into our country in 1990s,it has already become a primary mixture type on bituminous pavement in our country after research and promotion. Because of the difference between SMA and general bituminous concrete, it is very important to select and use the suitable graduation of SMA to ensure the dense frame work structure and excellent road performance of SMA.In this paper, we make a statistical for the performance index of three kinds of road material (basalt,diabase,granite) according to the actual application condition, and research the application of road material in different area of our country, to analyze widespread regulations of SMA material everyplace area in our country.Meanwhile, the data of SMA-16 and SMA13 in Chinese different periods and regions from 1996 is collected. Differences of key sieve are analyzed, and the character of SMA grading is researched in Chinese different regions. According to the application of different stage, the development feature and law of SMA grading is researched. The research finds that the obvious change exists in SMA16 from initial stage to present stage. Then, the common characteristics of SMA are proposed in Chinese present stage.According to the above research, the five of gradation are selected, that are the nether gradation on Standard; the nether gradation on Standard; the gradation which actual applications present stage of SMA16. Based on the Discrete Element theory, and simulated the three of gradation by the use of Particle Flow Code in 2 Dimensions (PFC2D) computer program, then, analyze the stability and the influential factors on the dense frame work structure among the five aggregate gradation, the results showed that the change of the pass ratio through 4.75mm sieve has important significance for the dense frame work structure of SMA.With the above investigation and research, we select the intermediate gradation which is similar to the optimum aggregate grading, and analyze the effect of fiber content and asphalt content also the compaction temperature on the structure indexes of SMA.