基于数字图像处理的粗集料棱角性量化研究

基于数字图像处理技术,对粗集料棱角性进行量化研究,以取代传统的试验方法。首先从单个颗粒的棱角性定义出发,建立了4个粗集料棱角性量化指标:AR、ARmax、AP、APc;然后采用数字图像处理(DIP)技术,对拍摄的粗集料二维图像进行处理分析,得到粗集料样本棱角性量化结果,最后将20份粗集料样本的未压实空隙率试验与DIP试验进行了比较。结果表明:4个用于评价粗集料棱角性的量化指标与未压实空隙率之间均有较强的相关性,其中以AP指标最佳;AP和APc指标更好地拉大了两个棱角性极端,有利于区分不同棱角性的粗集料。4个量化指标的面积加权平均值与未压实空隙率之间的相关系数均要大于它们的算术平均值与未压实空隙率之间的相关系数,这也表明经面积加权的棱角性指标考虑了粗集料的宏观性能,因此更加合理。

Quantification Research of Coarse Aggregate Angularity Based on Digital Image Processing

Existing test procedures for coarse angularity are time-consuming and labor-intensive and hard to work in a fast and accurate manner.In order to replace traditional tests,a quantitative analysis method for coarse aggregate angularity was presented based on Digital Image Processing(DIP).Firstly,four quantified indexes including AR,ARmax,AP and APc were established according to definition of angularity of individual particle,and the formula of calculations were proposed.Secondly,2D image of a coarse aggregate was captured,processed and analyzed by means of DIP technique to quantify the angularity of coarse aggregate.Finally,for the sake of verification,the uncompacted voids(UV) test of twenty coarse aggregate samples was made,and the experiment results were compared with that of DIP test.The study shows that strong correlations exist between the four indexes and the uncompacted voids.Among them,AP is the best one.AP and APc,which magnifying the ends of angularity,are better to distinguish all kinds of coarse aggregate angularity.For these indexes,the correlations between area weighted mean and UV are better than those between arithmetic mean and UV,which indicates the area weighted angularity indexes are more reasonable because of considering the macroscopic property of coarse aggregate.