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为了定量评价超大粒径沥青混合料(SLSM)的级配特性,运用分形理论提出了SLSM集料质量分形分布函数的计算方法,得到了不同级配SLSM-40的质量分形维数,建立了集料质量分布与分形维数的关联模型,分析了分形维数与SLSM-40体积指标的关系,并通过强度试验和简单性能试验研究了SLSM-40的力学指标。分析结果表明:分形维数在2.60左右时,SLSM-40的体积指标均符合技术要求;分形维数在2.55～2.60之间时,SLSM-40的级配均匀性良好;随着粒径增大,粘聚力增大,SLSM-40中粘聚力对整体强度贡献率约为50%,比普通沥青混合料提高了1～2倍,而内摩擦角减小5°～10°;20℃试验条件下,SLSM-40抗压回弹模量比AC-25提高了1 869MPa,为AC-25的2.6倍;不同试验温度条件下,随着加载频率的增大,SLSM-40的动态模量逐渐增大,相位角随温度和加载频率的变化规律与动态模量相比差异较大,并且温度越高,动态模量指标越小,SLSM-40的抗永久变形能力下降。
In order to quantitatively evaluate the gradation characteristics of ultra-large-size asphalt mixture (SLSM), the fractal theory was used to calculate the mass fractal distribution function of SLSM aggregates. The mass fractal dimensions of SLSM-40 with different gradations were obtained. The relationship model between the mass fraction and the fractal dimension was analyzed. The relationship between the fractal dimension and the volumetric index of SLSM-40 was analyzed. The mechanical index of SLSM-40 was also studied by the strength test and simple performance test. The analysis results show that the volumetric index of SLSM-40 meets the technical requirements when the fractal dimension is about 2.60. The SLSM-40 has good gradation uniformity when the fractal dimension is between 2.55 and 2.60. As the particle size increases , The cohesion increases, the contribution of the cohesion in SLSM-40 to the overall strength is about 50%, which is 1 to 2 times higher than that of ordinary asphalt mixture, while the internal friction angle is reduced by 5 ° -10 °; Under the test conditions, the compressive resilience modulus of SLSM-40 is 1 869MPa higher than that of AC-25, which is 2.6 times that of AC-25. Under different test temperature conditions, the dynamic modulus of SLSM- The phase angle increases with the increase of temperature and loading frequency, and the dynamic modulus of the phase angle increases greatly. The higher the temperature is, the smaller the dynamic modulus is. The anti-permanent deformation ability of SLSM-40 decreases.