RESEARCH ON THE RELATION BETWEEN THE PARTICLE SHAPE OF A COARSE AGGREGATE AND VOID CONTENT

摘要

To quantitatively characterize the shape of coarse aggregates, a needle flake gauge meter was used to sieve coarse aggregates. The image technique was used to carry out the operations of edge recognition, greying and image binarization. Image-Pro Plus was employed to obtain the grain-shape parameters of the coarse aggregates, including sphericity and flatness. Tested void contents were obtained for the coarse aggregates so that the relationship between the shape parameters (sphericity, flatness) and the accumulated void content was analyzed. The results showed that the minimum values of sphericity and flatness were 0.67 and 1.01 while the maximum values were 0.88 and 1.9, respectively. Sphericity was positively correlated with the void content of the coarse aggregate; on the contrary, flatness was negatively correlated with the void content. At the same condition of the mixture, compared to sphericity, flatness showed a higher correlation.