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细观结构特征对沥青混合料宏观性能有着重要影响,其中细观结构的空隙率特征是影响沥青混合料车辙、水损害的关键因素之一。通过工业CT分别对最大公称粒径分别为13mm与16mm的AC、SAC、SMA的6种沥青混合料试样进行无损扫描,获取其内部细观结构特征信息,并对其试样进行三维重构。提取试样的内部空隙体积参数并计算其三维空隙率;选取部分断面图像计算其二维空隙率,并对两种方法计算出的空隙率进行对比分析。研究结果表明:试样内部空隙数量随着空隙体积增大呈递减趋势,且0～50mm3体积区间内空隙数量最多;相同级配下,SAC的空隙率小于AC和SMA;最大公称粒径为13mm的空隙率小于16mm的空隙率;空隙率由试样两端向中间呈逐渐减小的趋势,且SMA较SAC表现得明显,最大公称粒径为16mm的试样比最大公称粒径13mm的表现得更明显;3D计算空隙率比2D计算空隙率更接近实测值。
The mesostructural features have an important influence on the macroscopic properties of asphalt mixtures. The porosity of mesostructures is one of the key factors affecting the rutting and water damage of asphalt mixtures. Through the industrial CT, six kinds of asphalt mixture specimens with the largest nominal diameter of 13mm and 16mm respectively AC, SAC and SMA were scanned non-destructively to get the information of their internal meso-structure characteristics, and their specimens were reconstructed in three dimensions . The internal void volume parameters of the sample were extracted and the three-dimensional void fraction was calculated. The two-dimensional void fraction was selected by partial section images, and the void ratios calculated by the two methods were compared. The results show that the number of voids in the sample decreases with the increase of the void volume, and the number of voids in the volume of 0 ~ 50mm3 is the largest. The void fraction of SAC is smaller than that of AC and SMA in the same gradation. The maximum particle size is 13mm Of the porosity of less than 16mm porosity; porosity from the sample ends to the middle of a gradually decreasing trend, and SMA was significantly SAC performance, the maximum nominal diameter of 16mm sample than the maximum nominal diameter of 13mm performance It is more obvious; the calculated void ratio of 3D is more close to the measured value than the calculated void ratio of 2D.