Shape and size of microfine aggregates: X-ray microcomputed tomography vs. laser diffraction

Microfine rock aggregates, formed naturally or in a crushing process, pass a #200 ASTM sieve, so have at least two orthogonal principal dimensions less than 75 μm, the sieve opening size. In this paper, for the first time, we capture true 3-D shape and size data of several different types of microfine aggregates, using X-ray microcomputed tomography (μCT) with a voxel size of 2 μm. This information is used to generate shape analyses of various kinds. Particle size distributions are also generated from the μCT data and quantitatively compared to the results of laser diffraction, which is the leading method for measuring particle size distributions of sub-millimeter size particles. By taking into account the actual particle shape, the differences between μCT and laser diffraction can be qualitatively explained.

The application of X-ray microcomputed tomography and spherical harmonic analysis to determining the three-dimensional shape and size distribution of sub-millimeter size particles was described and the results were used to evaluate results yielded by laser diffraction for the same material. Possible reasons for error in the laser diffraction results were discussed.Figure optionsDownload as PowerPoint slide