Fractal Theory On Graded Evaluation Of Asphalt Mixture And Research Of Road Performance

With the rapid development of highway construction in China since 1990s, early destroy happened in the asphalt pavement in large-scale construction process, especially by high temperature rutting. Chongqing is particularly prominent, because its high temperature lasting from June to September every year, longer than that in other places, with raining a lot from May to October. In addition, according to the heavy traffic, the asphalt mixture in Chongqing is asked for more stringent. Therefore, the way of figuring out the solution for mixture design gradation range for engineering using is urged to be found out.In this paper, research reports on asphalt pavement during the similar climatic zones home and abroad and the engineering experience is summarized. Raw materials commonly used in Chongqing area are selected, and four types of dense gradation mixes AC-20, AC-16 , AC-13 and SMA-13 are tested.Bulk density tests are used to determine the optimum proportions of coarse aggregate in the mixes, and the smaller voids in a mix are thought to be the better one. Five kinds of the shape of fine aggregate gradation calculated by 5 different N values are selected through Wheel Tracking Test and Freeze-Thaw Split Test to find the best of fine aggregate composition. The fractal theory was used to analyze the Fractal Characteristics of aggregate ,and find the variation between fractal and aggregates bulk,quality,grading curve,Marshall test parameters.Based on the best aggregate ratio, AC-13, AC-16, AC-20, SMA-13, the four types of asphalt mixtures for road performance of Rutting test, freeze-thaw splitting test had been taken. According to the test results, high stability and water stability in line with national norms of aggregate gradation are chosen. And it is recommended to adapt to Chongqing rational engineering design grading range with high temperature and wet areas, and gradation range of fractal dimension. The relationship with macro pavement performance and pavement microstructure had been established initially.