Estimation of 3D Sphericity by Volume Measurement – Application to Coarse Aggregates

Abstract

Abstract Wadell’s ‘true’ Sphericity is a traditional 3D particle geometry descriptor that quantifies the shape by comparing the particle’s surface area to the surface area of a sphere having the same volume as the particle. Despite the simplicity of definition and the capability to characterize the 3D shape, the true Sphericity has not been employed in the engineering practice due to the technical difficulty associated with the measurement of particle surface area. The recent advance in optical geo-characterization using 3D scanner has facilitated the surface area measurement, but which is still time-consuming and requires high computational cost to scan many particles to obtain a statistically reliable shape distribution. This paper introduces a new framework that can quickly estimate the particles’ true Sphericity with a minimal effort of 3D scanning. This approach leverages the relation between the particle surface-area-to-volume ratio (A/V) and volume (V) that can be approximated by a ‘power law’, which serves as the key information to estimate the 3D Sphericity by measuring the volume only. This paper demonstrates the feasibility of this new approach on a set of coarse aggregate.