矿料级配对多孔沥青混合料空隙分布特性的影响

Influence of Mineral Aggregate Gradation on Air Void Distribution Characteristic of Porous Asphalt Mixture

通过将X射线CT技术、数字图像处理技术与分形理论相结合,分析了矿料级配对多孔沥青混合料空隙率、空隙直径、空隙数量、空隙分维数等参数的影响规律。结果表明:随着空隙率的逐渐减小,空隙等效直径范围从空隙率为18.8%时的3.9～4.8mm减少到空隙率为4%时的1.5～2.9mm,空隙等效直径平均值从4.3mm降低到2.0mm;空隙数量、空隙率与等效直径沿试件高度方向分布规律较为一致;空隙轮廓分维数随着空隙率的不断减小而逐渐增大,且空隙轮廓分维数与空隙率呈现出显著的函数关系;多孔沥青混合料与普通沥青混合料空隙率的分界值约为14%;多孔沥青混合料空隙数量并不多,而是空隙等效直径较大。

Using X-CT technique, digital graphic processing technique and fractal theory, the influences of mineral aggregate gradation on air void percentage, air void diameter, air void quantity, air void fractal dimension were analyzed. The result indicates that the air void equivalent diameters decrease from 3.9-4.8 mm with 18.8% air void percentage to 1.5-2.9 mm with 4% air void percentage as air void percentage decreases, and the average values of air void equivalent diameters decrease from 4. 3 mm to 2. 0 mm. The distribution rules of air void quantity, air void percentage and air void equivalent diameter along depth direction are consistent. The fractal dimension of air void profile increases as air void percentage decreases and there exists functional relationship between fractal dimension of air void profile and air void percentage. The air void percentage of 14% is considered to be the dividing value between porous asphalt mixture and common asphalt mixture. Air void quantities of porous asphalt are less, but the air void equivalent diameters are larger.