Research On The Fractal Nature Of The Surface Microstructure Of Coarse Aggregate And The Relationship With The Anti-slide Performance Of Asphalt Pavement

The thesis comprehensively analysis the asphalt pavement skid resistance around domestic and international profile, and the influence of pavement skid resistance of a variety of subjective and objective factors were summarized and analyzed, made of coarse aggregate surface texture is a surface micro-structure sliding performance one of key influence factors, using the basic method of fractal surface fractal dimension of micro-texture analysis.Developed a coarse aggregate micro-texture image measurement, collection and analysis of computing complete sets of hardware and software measurement and analysis system, using non-contact measurement principle of laser triangulation imaging, combined with DC motor Chufa pulsed laser signal and record the lateral displacement of the methods issued by the laser beam on the measured aggregate to form a uniform surface scattering spot, scattering imaging in laser spot reflection point to accept the image plane, are things like the ratio between the displacement. Acquisition software is a common ActiveX controls and hardware systems for communications, control and data transmission, and various types of measurement error of the system conducted a comprehensive analysis, that the acquisition system of high precision, reliable and practical. Combined with the measurement system equipment, basic principles and parameters of indicators proposed laser, coarse aggregate surface characteristics and the measurement error of the environment, are analyzed in the level, respectively of the improved optimization, and the main indexes of the calibration and checksum against outside interference capability and measurement repeatability are also verified, the final measurement in extreme conditions on the smooth glass surface were measured The results show that the data measuring system stability, errors are controlled within an acceptable range. The introduction of fractal theory to the surface of coarse aggregate micro-texture image analysis of the fractal dimension calculated using the box counting method and the MATLAB programming platform on the texture fractal graphics computation, and the texture images were used to calculate and use of images corresponding to curve coordinate data to calculate the fractal dimension in two ways calculated by comparing the analysis, using micro-texture image method of calculating fractal dimension calculated sensitivity is good, the results between different types of stone obvious benefit analysis. At the same time, using standard KOCH fractal image to calibrate the process and efficacy, results consistent with the theoretically calculated data.Selected a road project has a common representation of granite, basalt, diorite, diabase, etc. were measured coarse aggregate basis, for further follow-up comparative study of selected one of two types of granite and basalt stone for tracking, Meanwhile, in order of the same type of stone the difference between different areas, we selected two regions were compared diabase. The selected surface texture of coarse aggregate fractal dimension decreasing order: basalt, diorite, granite and diabase, diabase two different dimensions of origin there are some differences, we in Selection When, on the same type of stone should be compared in detail to find out the difference.With trace measured on two Asphalt Pavement sliding surface using of the granite and basalt with which the attenuation of its stone surface texture and micro texture fractal dimension D values were about 8% of the decline occurred. On the other hand, have also been Sideway force coefficient SFC value of the tracking measurement, the lateral force coefficient of attenuation SFC value of about 21% -24% of differences between the decay rate, but the attenuation trend line, so you can explain the coarse aggregate tend to smooth the surface texture of the wear and tear, leading to friction against sliding down the road. On the other hand, fractal dimension about attenuation coefficient of road friction lateral force attenuation of 1 / 3, which also shows micro-texture of coarse aggregate impact of pavement skid resistance is an important factor.This surface texture measurement system developed high resolution, anti-interference ability, according to the system gives the sliding surface of asphalt pavement of coarse aggregate material selection of the fractal dimension control targets, given the surface micro-texture of coarse aggregate fractal dimension Measurement of D values and the basic requirements, and proposed pavement skid resistance material design process, the coarse aggregate micro-texture surface fractal dimension D value in the initial request and the completion detection range of the indicators proposed in the study area is a try and breakthroughs.