Mechanical Behaviour of Completely Decomposed Granite Soil with Tire Rubber Granules and Fibres

Mixing soil with waste tire rubber granules or fibres is a practical and promising solution to the problem of global scrap tire pollution. Before successful applications, the mechanical behaviour of the soil–rubber mixture must be thoroughly investigated. Comprehensive laboratory studies (compaction, permeability, oedometer and triaxial tests) were conducted on the completely decomposed granite (CDG)–rubber mixtures, considering the effects of rubber type (rubber granules GR1 and rubber fibre FR2) and rubber content (0–30%). Results show that, for the CDG–rubber mixture, as the rubber content increases, the compaction curves become more rubber-like with less obvious optimum moisture content. The effect on permeability becomes clearer only when the rubber content is greater than 30%. The shape effect of rubber particles in compression is minimal. In triaxial shearing, the inclusion of rubber particles tends to reduce the stiffness of the mixtures. After adding GR1, the peak stress decreases with the increasing rubber content due to the participation of soft rubber particles in the force transmission, while the FR2 results in higher peak stress especially at higher rubber contents because of the reinforcement effect. For the CDG–GR1 mixture, the friction angle at the critical state (φ’cs) decreases with the increasing rubber content, mainly due to the lower inter-particle friction of the CDG–rubber interface compared to the pure CDG interface, while for the CDG–FR2 mixture, the φ’cs increases with the increasing rubber content, again mainly due to the reinforcement effect.

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Effects of inclusion of granulated rubber tires on the mechanical behaviour of a compressive sand

Canadian Geotechnical Journal ◽

10.1139/cgj-2019-0112 ◽

2020 ◽

Vol 57 (5) ◽

pp. 763-769 ◽

Cited By ~ 4

Author(s):

W. Li ◽

C.Y. Kwok ◽

K. Senetakis

Keyword(s):

Particle Size ◽

Shear Strength ◽

Mechanical Behaviour ◽

Size Distributions ◽

Particle Size Distributions ◽

Rubber Content ◽

Filling Materials ◽

Rubber Particles ◽

Decomposed Granite ◽

Completely Decomposed Granite

Drained triaxial shearing tests were performed on a well-graded compressive sand (completely decomposed granite, CDG) and its mixtures with granulated rubber tires to investigate the effects of rubber size and content on their mechanical behaviour. Three sizes of rubber particles, GR1, GR2, and GR3, were used with size ratios to CDG (D50,rubber : D50,CDG) of 0.9, 3.5, and 7.2, respectively, and the rubber content ranged from 0% to 30%. The results show that for CDG–GR1 mixtures, the strength decreases with increasing rubber content, while for CDG–GR2 and CDG–GR3 mixtures, the strength decreases only at 10% rubber content and then increases markedly with increasing rubber content. The increase of strength is mainly because the inclusion of large rubber particles widens the particle size distributions of the mixtures, resulting in denser packings. The denser packings also lead to a decrease in compressibility. At larger size ratio and higher rubber content, the CDG–rubber mixtures show higher shear strength and lower compressibility than pure CDG, which indicates the CDG–rubber mixtures are very suitable to be used as filling materials.

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Thermodynamic-based cross-scale model for structural soil with emphasis on bond dissolution

Canadian Geotechnical Journal ◽

10.1139/cgj-2020-0677 ◽

2021 ◽

Author(s):

Wei Zhang ◽

Jia-qiang Zou ◽

Kang Bian ◽

Yang Wu

Keyword(s):

Constitutive Model ◽

Bond Strength ◽

Scale Model ◽

Triaxial Tests ◽

Natural Soil ◽

Engineering Practice ◽

Compression Tests ◽

Strength Deterioration ◽

Decomposed Granite ◽

Completely Decomposed Granite

The immersion weakening effect of natural soil has always been a difficult problem encountered in geotechnical engineering practice. The bond dissolution is a common cause of soil strength deterioration, which remains not well understood yet. In this study, a thermodynamic-based constitutive model of structural soils based on the α model is first established, considering the bond strength by modifying the yield surface size and gradually reducing the bond strength with the development of plastic strain. Furthermore, by taking the meso-mechanisms of bond dissolution into account, the evolution rule of the free energy during the bond dissolution process is derived based on a homogenization approach, and a thermodynamic-based constitutive model of structural soil with bond dissolution is thereafter developed. By comparing with the results of one-dimensional compression tests and conventional triaxial tests, the model is verified to be capable of reflecting the gradual destructuration process of soil while loading. The comparison with triaxial test results of completely decomposed granite after different immersion durations and parametric studies show that based on the cross-scale energy equivalence, the model can well reflect the strength deterioration characteristics of completely decomposed granite with bond dissolution mechanisms at the mesoscale fully considered.

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An Evaluation of the Resilient Modulus and Permanent Deformation of Unbound Mixtures of Granular Materials and Rubber Particles from Scrap Tyres to Be Used in Subballast Layers

Libro de Actas CIT2016. XII Congreso de Ingeniería del Transporte ◽

10.4995/cit2016.2016.4231 ◽

2016 ◽

Author(s):

Carlos Hidalgo Sgnes

Keyword(s):

Granular Materials ◽

Resilient Modulus ◽

Permanent Deformation ◽

Waste Material ◽

Triaxial Tests ◽

Rubber Content ◽

Cyclic Triaxial ◽

Cyclic Triaxial Tests ◽

Vibration Attenuation ◽

Rubber Particles

Over the last years rubber from scrap tyres has been reused in different civil works such as road embankments and railway platforms due to its resilient properties, low degradation and vibration attenuation. Unfortunately, this issue is still scarce. For instance, in Spain about 175.000 tonnes of scrap tyres were collected in 2014, of which only 0.6% were reused in civil works. Aiming to contribute to the reutilisation of large quantities of this waste material, this paper focuses on the analysis of unbound mixtures of granular materials with different percentages of rubber particles to be used as subballast layers. Mixtures are tested under cyclic triaxial tests so as to obtain their resilient modulus and evaluate their permanent deformations. It is found that as the rubber content increases, the resilient modulus decreases and the permanent deformation increases. Taking into account the usual loads transmitted to the subballast layer, the optimum rubber content that does not compromise the behaviour of the mixture is set in a range between 2.5% and 5% in terms of weight.DOI: http://dx.doi.org/10.4995/CIT2016.2016.4231

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Discrete element modelling of the mechanical behaviour of a sand-rubber mixture containing large rubber particles

Construction and Building Materials ◽

10.1016/j.conbuildmat.2019.01.214 ◽

2019 ◽

Vol 205 ◽

pp. 574-585 ◽

Cited By ~ 2

Author(s):

Linxian Gong ◽

Lei Nie ◽

Yan Xu ◽

Hong Wang ◽

Tao Zhang ◽

...

Keyword(s):

Mechanical Behaviour ◽

Discrete Element ◽

Discrete Element Modelling ◽

Rubber Mixture ◽

Element Modelling ◽

Rubber Particles

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Study the Relationship of Accumulation Residual Strain and the Loading Number of Completely Decomposed Granite and Cement Improved Soil

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.243-249.4257 ◽

2011 ◽

Vol 243-249 ◽

pp. 4257-4260

Author(s):

Wen Yi ◽

Yong He Wang ◽

Tian Tian Deng ◽

Hong Bing Xiao

Keyword(s):

Plastic Deformation ◽

Residual Strain ◽

High Speed ◽

Dynamic Stress ◽

Good Condition ◽

Dynamic Strength ◽

Triaxial Tests ◽

Decomposed Granite ◽

Completely Decomposed Granite ◽

Residual Plastic Deformation

This paper based on the dynamic triaxial tests of completely decomposed granite samples of the Wuhan-Guangzhou passenger line to study the relation of the accumulated residual strain and the load times of completely decomposed granite and cement improved soil, and analyzes whether they meet the dynamic strength and cumulative cyclic deformation indicators and requirements of high-speed railway under vehicles load. High-speed driving when the subgrade generate residual plastic deformation. Residual plastic deformation of the continuous development will inevitably lead to the deterioration of the road, such as cracks, jack mud, uneven subsidence and long-term slow subsidence of the roadbed. Therefore, by studying the dynamic strength and the size of the dynamic stress of different parts of subgrade embankment to determine the appropriate filling parts of filler and control the final dynamic stress level of the roadbed at a reasonable range in order to ensure lines in good condition in the design life.

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Shear strength characteristics of two saprolitic soils

Canadian Geotechnical Journal ◽

10.1139/t96-085-307 ◽

1996 ◽

Vol 33 (4) ◽

pp. 595-609 ◽

Cited By ~ 43

Author(s):

Julian K-M Gan ◽

D G Fredlund

Keyword(s):

Shear Strength ◽

Characteristic Curve ◽

Matric Suction ◽

Coarse Grained ◽

Triaxial Tests ◽

Direct Shear ◽

Strength Behavior ◽

Decomposed Granite ◽

Insight Into ◽

Completely Decomposed Granite

The saturated and unsaturated shear strength behavior of an undisturbed, completely decomposed fine ash tuff and an undisturbed, completely decomposed granite from Hong Kong were studied using direct shear and triaxial tests. The completely decomposed fine ash tuff is a fine- to medium-grained saprolite. The completely decomposed granite is a coarse-grained saprolite. Results show that matric suction increases the shear strength of both soils. The extent of the increase is the shear strength with matric suction is related to the soil-water characteristic curve for the soil and to the amount of dilation during shear. The effect of matric suction on the shear strength was more pronounced for the fine- to medium-grained completely decomposed fine ash tuff than for the coarse-grained completely decomposed granite. These studies on the saprolitic soils provide insight into the understanding of the shear strength of unsaturated, coarse-grained soils. Key words: saprolites, shear strength, matric suction, triaxial, direct shear, coarse-grained soils.

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Analysis of the bearing capacity of unbound granular mixtures with rubber particles from scrap tyres when used as sub-ballast

Materiales de Construcción ◽

10.3989/mc.2016.11515 ◽

2016 ◽

Vol 66 (324) ◽

pp. 105 ◽

Cited By ~ 2

Author(s):

C. Hidalgo-Signes ◽

P. Martínez-Fernández ◽

J. Garzón-Roca ◽

R. Insa-Franco

Keyword(s):

Bearing Capacity ◽

Field Tests ◽

Triaxial Tests ◽

Rubber Content ◽

Cyclic Triaxial ◽

Cyclic Triaxial Tests ◽

Granular Mixtures ◽

Rubber Particles ◽

Load Tests ◽

Plastic Creep

Scrap tyres are a problematic waste material. As a method for recycling large quantities of rubber from scrap tyres, this paper analyses the use of unbound granular mixtures with varying percentages of rubber particles as sub-ballast in railway lines. Bearing capacity for such mixtures is studied in laboratory and field tests using static and dynamic plate load tests, as well as cyclic triaxial tests. It is found that adding rubber increases permanent and resilient strain and that none of the mixtures suffer plastic creep after 2.5 million cycles. Considering the usual bearing capacity requirements, the optimum rubber content is 2.5% (by weight). This percentage increases resistance to degradation while ensuring sufficient bearing capacity.

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Strain induced crystallization in vulcanized natural rubber containing ground tire rubber particles with reinforcement and nucleation abilities

Polymer Testing ◽

10.1016/j.polymertesting.2021.107313 ◽

2021 ◽

pp. 107313

Author(s):

Nicolas Candau ◽

Oguzhan Oguz ◽

Carlos Eloy Federico ◽

Gregory Stoclet ◽

Jean-François Tahon ◽

...

Keyword(s):

Natural Rubber ◽

Tire Rubber ◽

Ground Tire Rubber ◽

Rubber Particles ◽

Strain Induced Crystallization ◽

Induced Crystallization

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Shear strength and dilative characteristics of an unsaturated compacted completely decomposed granite soil

Canadian Geotechnical Journal ◽

10.1139/t10-015 ◽

2010 ◽

Vol 47 (10) ◽

pp. 1112-1126 ◽

Cited By ~ 42

Author(s):

Md. Akhtar Hossain ◽

Jian-Hua Yin

Keyword(s):

Shear Strength ◽

Normal Stress ◽

Matric Suction ◽

Water Retention Curve ◽

Direct Shear ◽

Normal Stresses ◽

Soil Water Retention Curve ◽

Strength Data ◽

Decomposed Granite ◽

Completely Decomposed Granite

Shear strength and dilative characteristics of a re-compacted completely decomposed granite (CDG) soil are studied by performing a series of single-stage consolidated drained direct shear tests under different matric suctions and net normal stresses. The axis-translation technique is applied to control the pore-water and pore-air pressures. A soil-water retention curve (SWRC) is obtained for the CDG soil from the equilibrium water content corresponding to each applied matric suction value for zero net normal stress using a modified direct shear apparatus. Shear strength increases with matric suction and net normal stress, and the failure envelope is observed to be linear. The apparent angle of internal friction and cohesion intercept increase with matric suction. A greater dilation angle is found at higher suctions with lower net normal stresses, while lower or zero dilation angles are observed under higher net normal stresses with lower suctions, also at a saturated condition. Experimental shear strength data are compared with the analytical shear strength results obtained from a previously modified model considering the SWRC, effective shear strength parameters, and analytical dilation angles. The experimental shear strength data are slightly higher than the analytical results under higher net normal stresses in a higher suction range.

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