The influence of particle shape and mineralogy on the particle strength, breakage and compressibility

Xiaoyan Zhang,Ting Yao,Beatrice A Baudet

doi:10.1186/s40703-020-0108-4

Xiaoyan Zhang, Ting Yao + Show 1 more

Open Access

https://doi.org/10.1186/s40703-020-0108-4

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Abstract

It is widely accepted that both particle shape and mineralogy could have a great effect on the particle strength. However, due to the complexity of nature grains, it is difficult to distinguish the influence of particle shape from mineralogy. This paper shows measurements of the particle shape and mineralogy of carbonate sand, completely decomposed granite, Leighton Buzzard sand and pumice sand. The particle shape of carbonate sand and completely decomposed granite is similar, but the mineral of carbonate sand is carbon dioxide while the mineral of completely decomposed granite is mica and feldspar. It is found that the single particle strength of completely decomposed granite is higher than that of carbonate sand, and the particle breakage caused by one-dimensional compressing tests of completely decomposed granite is higher than that of carbonate sand. The mineralogy of both completely decomposed granite and Leighton Buzzard sand are quartz, but completely decomposed granite is more heterogeneous, result in the single particle strength of completely decomposed granite is much lower than that of Leighton Buzzard sand. It is also found the particle breakage from the one-dimensional compression test for completely decomposed is larger than Leighton Buzzard sand. It should be noted that carbonate sand is stronger than completely decomposed granite after quantitatively analysis the particle shape, particle breakage and compressibility behavior although carbonate sand has extremely irregular shape such as a branch shape, and also several pores. On the other hand, although Leighton Buzzard sand, completely decomposed granite and also pumice sand to some extent have composition of silica, the crystal of those three is completely different, result in the strength or compressibility are quite different. It seems that particle shape is not a major factor to affect strength or compressibility, but the mineralogy could be a major factor.

Highlights

Particle breakage plays an important role in determining the constitutive relation for granular materials at high or medium high stress
carbonate sand (CS) as a product of corals, mollusc shells and algae was considered as a very irregular and fragile material like Dog’s Bay sand [12, 15, 31], or contains several intra-voids [38], but it is surprising to note that AR50 of completely decomposed granite (CDG) is smallest among four kinds of materials, which indicate that CDG could be the most irregular material instead of CS from statistic quantification
Mica and feldspar within CDG were measured separately by single particle crushing tests, and it was found that the 37% survival possibility strength of mica with size of 0.6–1.18 mm is 94.8 MPa, while that of feldspar is 38.1 MPa

Summary

Introduction

Particle breakage plays an important role in determining the constitutive relation for granular materials at high or medium high stress. Single particle crushing tests were carried out to determine average tensile strength on a wide range of size of grains and verity of minerals [7, 20, 30, 41]. This paper focus on investigating the influence of particle shape and mineralogy on average tensile strength, particle breakage and compressibility.

Results

Conclusion