Research On Application Of Fractal Theory For Asphalt Mixtures

In recent years, express highway develops at full speed in our country, asphalt pavement on the highway in the increasingly large, the study of asphalt mixture more depth. There are so many self-similarity characteristics in asphalt mixture from the selection of raw materials, the design of gradation, until to the construction of pavement. Traditional indexes based on experience are difficult in describing and evaluating, so we can turn to the fractal theory to give them a quantitative analysis. Fractal is a new theoretical tool to study lots of statistical self-similarity characteristics in nature, and it has a powerful function in describing and evaluating those phenomena continuous in scale, erose in shape or stochastic in distribute. Fractal theory has been regarded as a hotspot-issue of asphalt mixture study.The fractal method is using the fractal theory of an important parameter of fractal dimension to describe asphalt mixture to derive particle size distribution function and mineral aggregate gradation .Gradation of the three pilot study of fractal: SMA-13,AC-13C,OGFC-13,Guang-Shao expressway used to provide the granite, limestone, slag, etc, the mineral aggregate gradation evaluation of the fractal model based on the pilot study and theoretical analysis.Asphalt-aggregate ratio is used by 6.0% and 6.3% of SMA-13 coarse, medium and fine three gradations for the test, fractal dimension may have different influences on Marshall Stability, voids in mineral aggregate, percentage of voids, saturation cleavage streng and thresidual stability of asphalt mixture. Results indicate fractal theory that can be used study of asphalt mixture and guided the design of gradation.Through the SMA-13 with nine directions of fractal analysis, fractal dimension may have influences on dynamic stability and Marshall Test volume targets, the trend of SMA gradation is made through the principle of selection.Graded in four anti-slide for the study: SMA-13,AC-13C,OGFC-13,AC-13F, Anti-sliding performance of asphalt pavement on the use of fractal analysis and evaluation. Analying the relationship between structural sub-section dimension with slag content, fine aggregate as well as texture depth .To some extent, sub-section dimension takes into account the macro-and micro-surface structure, and from the size and density structure of both the roughness of the pavement evaluation. Therefore, the structural fractal dimension is more suitable for performance evaluation of anti-sliding than texture depth.