基于CT数字图像处理的沥青混合料车辙试件空隙特征测定

摘要

为了研究沥青混合料标准车辙试件试验前后空隙分布特征,采用医用CT扫描设备获取了大量车辙试件图像,将图像导入Matlab图像处理软件进行图像增强处理,采用大津法(OTSU)选取全局阈值实现图像的分割.在此基础上,对比SBS改性沥青混合料和普通沥青混合料车辙试件空隙特征及其变化的差异.结果表明:采用本方法测定的空隙率均值与实验室测量的空隙率一致,并且本方法能从细观层面反映空隙分布特征.轮碾成型原始车辙试件的空隙率在轮载作用处偏小,二维平面上空隙面积在10 m m2以下居多;车辙试验后,辙槽处空隙率大幅度下降,普通沥青混合料试件车辙深度更深,空隙数量减少更明显,空隙特征的变化主要体现在小徽空隙上.%In order to quantify air voids,distribution characteristics of asphalt mixture standard rutting specimens before and after the test,this paper adopts the medical CT scanning equipment to obtain a large amount of rutting specimen images,puting into the Matlab image processing software for image enhancement processing,using the Da-Jin (OTSU) to select the global threshold for image segmentation.On this basis,comparing rut specimen of the SBS modified asphalt mixture and common asphalt mixture in differences of air voids characteristics and changes.The results show that using this method for determining the average air void consistent with the air void laboratory measure,and It can reflect the characteristics of the space distribution from the mesoscopic level.The air void of the grinding wheel original rutting molding specimens smaller in load place,air voids area under 10 mm2 was mostly in a two-dimensional plane;After Rutting test,the air void dropped substantially,the common asphalt mixture specimen rutting depth deeper,air void decreased more significantly,the change of the air void characteristics mainly reflects on the small air void.