Morphology of Limestone Manufactured Sand Based on Image Processing Technology

To quantitatively study the morphological characteristics and regularity of limestone manufactured sand with different particle sizes, digital images of 6 size fractions in total, 4.750-2.360, 2.360-1.180, 1.180-0.600, 0.600-0.300, 0.300-0.150 mm and 0.150-0.075 mm (sample size of each size fraction is 500), were collected by digital camera and stereomicroscope. Based on digital image processing (DIP), the circularity,aspect ratio and sphericity of samples were quantitatively determined using software Image-Pro Plus. While the fractal dimension of limestone manufactured sand was calculated according to fractal theory. Besides, statistical analysis was used for the morphology characteristics, and the morphology parameters of limestone manufactured sand and river sand were compared. The results indicate that the circularity,aspect ratio and sphericity of limestone manufactured sand with different sizes basically obey the normal distribution. For different size fractions,the changes of circularity,aspect ratio,sphericity and fractal dimension are consistent,signifying that the morphology parameters of limestone manufactured sand or river sand can be characterized by either one of these parameters.The circularity,aspect ratio and sphericity of limestone manufactured sand are 0.834-0.857, 0.693-0.705 and 0.793-0.799, less than those of river sand by 5.0%,7.2% and 3.3%, respectively,while its fractal dimension reaches 1.046-1.056, higher than that of the river sand by 3.2%. Finally, the recommended ranges of roundness, aspect ratio, sphericity and fractal dimension in the process of manufactured sand shaping were provided, i.e., 0.880-1.000,0.740-1.000, 0.820-1.000 and 1.010-1.025.