Sand–rubber mixtures undergoing isotropic loading: derivation and experimental probing of a physical model

Abstract

The volume of scrap tyres, an undesired urban waste, is increasing rapidly in every country. Mixing sand and rubber particles as a lightweight backfill is one of the possible alternatives to avoid stockpiling them in the environment. This paper presents a minimal model aiming to shed light on the relevant physical parameters governing the evolution of the void ratio of sandrubber mixtures undergoing an isotropic compression loading, where the mixtures consist of various volume ratios of rubber. It is based on the idea that, when pressure is applied, the rubber particles deform and partially fill the porous space of the system, leading to a decrease of the void ratio with increasing pressure. We show that our simple approach is capable of reproducing experimental data obtained with sand and rubber of similar particle size distributions up to mixtures composed of 50% of rubber. The effect of the particle shape and size on the model parameters is discussed.

Compaction of mixtures of rigid and highly deformable particles: A micromechanical model

“…The compaction of soft granular matter, especially beyond the jamming point, is a broad issue increasingly studied in the literature. Innovative experiments [26][27][28][29][30][31] and advanced numerical methods (including discrete element methods [31][32][33][34][35][36], meshless approaches [29,37,38], and coupled finite-discrete element methods [39][40][41][42]) have made it possible to take a step forward in the understanding of the microstructural evolution beyond the jamming point. However, a theoretical modeling of the compaction process is still missing.…”

“…For assemblies of two distinct solid granular phases (i.e., for binary mixtures), the, so far, adopted strategies consist of using existing compaction equations for a single granular phase and free-parameter fitting [42,61]. However, an attempt to predict the compaction behavior of mixtures of rigiddeformable particles can be attributed to Platzer et al [29], who studied mixtures of sand with rubber particles. They introduced an equation involving four parameters and deduced from the assumption that the empty space is filled as a first-order differential equation of the applied pressure.…”

Compaction Model for Highly Deformable Particle Assemblies

“…We focus this work on the compaction behavior of deformable grain assemblies beyond jamming, a subject widely investigated, of major industrial and engineering significance, yet misunderstood. The compaction of deformable matter has been addressed in experiments using ceramic, metallic, and pharmaceutical powders [1][2][3][4][5], gels [6][7][8], rubberlike particles [9][10][11][12], and even blood cells [13]. More recently, developments of numerical approaches based on meshless methods [14][15][16], the discrete element method [17,18], or the coupled finite element-discrete element methods [11,[19][20][21][22][23][24] have enabled the exploration of the physics of deformable granular media.…”

Particle–scale interactions and energy dissipation mechanisms in sand–rubber mixtures

“…As this happens the volume of voids reduces (filled by deformed rubber particles) and the contact area increases between both rubber and sand particles. Rubber particles can then fulfil two different roles: one which participates in the loading transmission and the other which acts like a void inert portion (Platzer et al, 2018). Whilst the behaviour of rubber particles can be expected to be nearly elastic, the inter-particle friction in rubber is significantly high (e.g.…”