A Quantitative Evaluation of Size and Shape Characteristics for Desert Sand Particles

Abstract

In this paper, the size and shape characteristics of desert sand particles were quantitatively investigated via a combination of X-CT scanning and spherical harmonics functions. The size characteristics of the desert sand particles were evaluated via the Length (L), Width (W), Thickness (T), and Volume equivalent spherical diameter (VESD). The average value of the VESD for the desert sand particle is 118.2 m, which is much smaller than that of commonly used fine aggregate, and more than 90% particles are smaller than 150 m. The overall shape of the desert sand particles was assessed with two aspect ratios: elongation (EI) and flatness (FI). Desert sand particles were classified into four categories: spheroid-shaped, oblate-shaped, prolate-shaped, and blade-shaped. The sphericity (S) values of the desert sand particles were distributed in a wider range, with an average sphericity of 0.85, much larger than that of commonly used fine aggregates. Through a combination of aspect ratios and sphericity analysis, it can be roughly concluded that the desert sand particles appear in more irregular shapes, but with relatively smooth surface morphology and less convex or concave parts.