基于X-ray CT的沥青混合料空隙测试精度影响因素分析

Analysis of influencing factors of the test precision of asphalt mixture voids based on X-ray CT

为了分析细观尺度下沥青混合料空隙率测试精度的影响因素,采用德国Phoenix v|tome|x S240型工业X-ray CT机,结合正交试验设计与方差分析,研究不同CT参数及级配类型对沥青混合料三维重构体积参数的影响.通过对不同级配类型马歇尔试件扫描并进行三维重构与体积分析,建立影响因素与空隙率测试结果之间的关系,进而确定最优扫描参数.试验结果表明,基于细观尺度对沥青混合料进行三维体积分析是可行的;扫描电压、电流及级配类型对重构结果有不同程度的影响;适当提高电压、电流及选择恰当的滤波片可提高测试结果的准确性;在恰当的设备参数条件下,基于细观尺度与宏观尺度下得到的沥青混合料空隙率具有良好的相关性,有助于提高测试结果的准确性与试验的经济性.

To study the factors that influence the test precision of percent air voids of asphalt mixture based on mesoscopic scale, German Phoenix v ｜ tome ｜ x S240 industrial X-ray CT was utilized in combination with orthogonal test and variance analysis to study how different CT parameters and gradation types influenced the 3D reconstruction volume parameters of asphalt mixture. Marshall specimens were scanned by changing the parameters of CT and gradation types of asphalt mixture and the results were used for three-dimensional analysis, the relation between influence factors and percent air voids was also built, and then determine the optimal scanning parameters. The test results showed that it is feasible to make three-dimensional volume analysis of asphalt mixture on the basis of meso-scale; the scanning parameters and gradation types have different levels of effects on reconstruction results; the test accuracy would be improved by increasing scaning voltage and current properly and as well as choosing the appropriate filters. The percent air voids that obtained on the base of both meso-scale and macro-scale had good correlation under the condition of appropriate parameter of apparatus, in addition can improve the accuracy and economy of the test.