Effect of Particle Morphology on Stiffness, Strength and Volumetric Behavior of Rounded and Angular Natural Sand

Abstract

Stress–strain and volume change behavior for clean sands which have distinct particle shape (rounded and angular) with very similar chemical (mineralogical) composition, size, and texture in one-dimensional (1D) compression and drained triaxial compression are presented. The effect of particle morphology on the crushing behavior in one-dimensional loading is explored using laser light diffraction technique which is suitable for particle crushing because of its high resolution and small specimen volume capability. Particle size distribution in both volume/mass and number distributions are considered for improved understanding associated with the process of comminution. Number distributions present a clearer picture of particle crushing. It is argued that particle crushing in granular assemblies initiates in larger particles, rather than in smaller particle. It was found that rounded sand specimens showed greater crushing than angular sand specimens with higher uniformity coefficient. In 1D compression, loose specimens compress approximately 10% more than dense specimens irrespective of particle shape. Densification of angular sand results in improvement in stiffness (approximately 40%) and is comparable to that of loose rounded sand. In general, density has a greater influence on the behavior of granular materials than particle morphology. The effect of particle shape was found to be greater in loose specimens than in dense specimens. The effect of grain shape on critical state friction angle is also quantified.

An Image-Based Gradation Calculation Method considering Crushed Stone Morphology

“…Recently, with the application of the computer image processing technology, the accuracy of the particle shape measurements has been improved. An image-based method is known to be a relatively convenient and accurate method, which can obtain particle shape data by using image processing software [22][23][24][25][26][27][28][29][30][31][32][33][34]. Basically, particles are usually pictured finely or roughly and the photos are processed in specific software such as ImageJ [22,31,33] and OnDemand3D [34] to obtain the particle shape indices.…”

“…An image-based method is known to be a relatively convenient and accurate method, which can obtain particle shape data by using image processing software [22][23][24][25][26][27][28][29][30][31][32][33][34]. Basically, particles are usually pictured finely or roughly and the photos are processed in specific software such as ImageJ [22,31,33] and OnDemand3D [34] to obtain the particle shape indices. Some researchers used professional instruments to measure the particle shape of sand and review the particle shape effect on mechanical behavior such as QIC-PIC [23,24,29], Sedimaging [26], and CX2 [32] systems.…”