Mechanical Behavior of Sand Mixed with Rubber Aggregates

The main objective of this study is to compare the mechanical behavior of two sands (Hostun or Dune sands) mixed with crushed rubber obtained from used tires. However, it is essential to ensure that his geotechnical application do not result in long-term negative impacts on the environment. The chemical properties of these two sands are given by energy dispersive analysis X-ray fluorescence spectrometry. The mineral composition of these two sands is performed by X-ray diffractometry. The morphological characteristics of the sand grains are given by the analysis of the images of the two sands given by the scanning electron microscope. This study is based on 120 direct shear tests performed on sand-rubber aggregate mixtures. The results show that the rubber content of the aggregates has a significant effect on the shear strength of sand-rubber mixtures in both cases of sand. In fact, the shear strength of the sand-rubber mixture increases with increasing crushed rubber up to 20% for different normal stresses. The analysis of the test results also shows the effect of the angular shape of the sand grains on the interparticle friction. The contribution of the structure effect in the mobilized friction is analyzed by comparing the shear test results of Hostun and dune sand mixtures.

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Mechanical Properties of Fly Ash-Slag-Dredged Silt System Stimulated by Alkali

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.807-809.1140 ◽

2013 ◽

Vol 807-809 ◽

pp. 1140-1146 ◽

Cited By ~ 2

Author(s):

Yi Xuan Chen ◽

Xiu Li Sun ◽

Zhi Hua Li

Keyword(s):

Mechanical Properties ◽

Shear Strength ◽

Fly Ash ◽

Construction Materials ◽

Xrd Analysis ◽

Test Results ◽

X Ray Diffraction ◽

Shear Tests ◽

X Ray ◽

Direct Shear Tests

The objective of this work is to investigate the stimulation effect of the addition of alkali on the fly ash and slag for stabilizing dredged silt. Based on the test results, a viable alternative for the final disposal of dredged silt as subgrade construction materials were proposed. For this purpose, several mixtures of dredged silt-fly ash-slag and alkali were prepared and stabilized/solidified. In this system, fly ash and slag were used as hardening agents (solidified materials) of dredged silt and alkali was used as activator of fly ash and slag. The shear strength of the mixture was tested by several direct shear tests. Furthermore, X-Ray Diffraction (XRD) analysis was used to determine the hydration products of the system. The specimens were tested in order to determine the shear strength changes versus hydration time and the alkali content. It is indicated that mechanical properties of solidified silt are improved significantly by addition of fly ash and slag stimulated by alkali.

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Mechanical Properties and Micro Mechanism of Nano-Clay-Modified Soil Cement Reinforced by Recycled Sand

Sustainability ◽

10.3390/su13147758 ◽

2021 ◽

Vol 13 (14) ◽

pp. 7758

Author(s):

Biao Qian ◽

Wenjie Yu ◽

Beifeng Lv ◽

Haibo Kang ◽

Longxin Shu ◽

...

Keyword(s):

Shear Strength ◽

Void Ratio ◽

Soil Mass ◽

Direct Shear ◽

Test Results ◽

The Sustainable Development ◽

Direct Shear Tests ◽

Soil Cement ◽

Nano Clay ◽

New Material

To observe the effect of recycled sand and nano-clay on the improvement of the early strength of soil-cement (7d), 0%, 10%, 15% and 20% recycled sand were added. While maintaining a fixed moisture content of 30%, the ratios of each material are specified in terms of soil mass percentage. The shear strength of CSR (recycled sand blended soil-cement) was investigated by direct shear test and four groups of specimens (CSR-1, CSR-2, CSR-3 and CSR-4) were obtained. In addition, 8% nano-clay was added to four CSR groups to obtain the four groups of CSRN-1, CSRN-2, CSRN-3 and CSRN-4 (soil-cement mixed with recycled sand and nano-clay), which were also subjected to direct shear tests. A detailed analysis of the modification mechanism of soil-cement by recycled sand and nano-clay was carried out in combination with scanning electron microscopy (SEM) and IPP (ImagePro-Plus) software. The test results showed that: (1) CSR-3 has the highest shear strength due to the “concrete-like” effect of the incorporation of recycled sand. With the addition of 8% nano-clay, the overall shear strength of the cement was improved, with CSRN-2 having the best shear strength, thanks to the filling effect of the nano-clay and its high volcanic ash content. (2) When recycled sand and nano-clay were added to soil-cement, the improvement in shear strength was manifested in a more reasonable macroscopic internal structure distribution of soil-cement. (3) SEM test results showed that the shear strength was negatively correlated with the void ratio of its microstructure. The smaller the void ratio, the greater the shear strength. This shows that the use of reclaimed sand can improve the sustainable development of the environment, and at the same time, the new material of nano-clay has potential application value.

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Strength Tests and Numerical Simulations of Loess Modified by Desulfurization Ash and Fly Ash

Materials ◽

10.3390/ma15020512 ◽

2022 ◽

Vol 15 (2) ◽

pp. 512

Author(s):

Zhi Cheng ◽

Xinrong Cheng ◽

Yuchao Xie ◽

Zhe Ma ◽

Yuhao Liu

Keyword(s):

Shear Strength ◽

Fly Ash ◽

Power Plants ◽

Utilization Rate ◽

Direct Shear ◽

Test Results ◽

Mass Ratio ◽

Direct Shear Tests ◽

Strength Tests ◽

Actual Test

Desulfurization ash and fly ash are solid wastes discharged from boilers of power plants. Their utilization rate is low, especially desulfurization ash, most of which is stored. In order to realize their resource utilization, they are used to modify loess in this paper. Nine group compaction tests and 32 group direct shear tests are done in order to explore the influence law of desulfurization ash and fly ash on the strength of the loess. Meanwhile, FLAC3D software is used to numerically simulate the direct shear test, and the simulation results and the test results are compared and analyzed. The results show that, with the increase of desulfurization ash’s amount, the shear strength of the modified loess increases first and then decreases. The loess modified by the fly ash has the same law with that of the desulfurization ash. The best mass ratio of modified loess is 80:20. When the mass ratio is 80:20, the shear strength of loess modified by the desulfurization ash is 12.74% higher than that of the pure loess on average and the shear strength of loess modified by fly ash is 3.59% higher than that of the pure loess on average. The effect of the desulfurization ash on modifying the loess is better than that of the fly ash. When the mass ratio is 80:20, the shear strength of loess modified by the desulfurization ash is 9.15% higher than that of the fly ash on average. Comparing the results of the simulation calculation with the actual test results, the increase rate of the shear stress of the FLAC3D simulation is larger than that of the actual test, and the simulated shear strength is about 8.21% higher than the test shear strength.

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Effect of fibre content and structure on anisotropic elastic stiffness and shear strength of peat

Canadian Geotechnical Journal ◽

10.1139/t2012-003 ◽

2012 ◽

Vol 49 (4) ◽

pp. 403-415 ◽

Cited By ~ 29

Author(s):

Michael T. Hendry ◽

Jitendra S. Sharma ◽

C. Derek Martin ◽

S. Lee Barbour

Keyword(s):

Shear Strength ◽

Confining Pressure ◽

Deviatoric Stress ◽

Direct Shear ◽

Shear Tests ◽

Direct Shear Tests ◽

A Value ◽

Frictional Strength ◽

Fibrous Peat ◽

Interparticle Friction

This paper presents the results of a laboratory testing program involving consolidated undrained triaxial tests and direct shear tests on remoulded peat, remoulded peat fibre, and Shelby specimens of peat obtained from a field site located in the Edson subdivision of the Canadian National railway in Alberta, Canada. These results were analyzed within the frameworks of elastic behaviour of cross-anisotropic materials and shear strength of fibre-reinforced soil. Shelby specimens were found to be inherently cross-anisotropic, whereas the remoulded peat and peat fibre specimens showed a transition from isotropic to cross-anisotropic with increasing vertical strain and effective confining pressure. The horizontal stiffness of Shelby specimens was found to be 2.6 to 2.9 times their vertical stiffness. The shear strength of intact peat is made up of interparticle friction as well as tension in the peat fibres. A novel procedure for estimating the interparticle frictional strength of fibrous peat from CU triaxial test results is proposed. It involves extrapolating the linear strain-hardening portion of the stress–strain curve to obtain the deviatoric stress at zero axial strain and plotting the deviatoric stress values thus obtained against initial mean effective confining pressure to obtain the frictional strength. Using this procedure, a value of 31° was obtained for the interparticle friction, which compares favourably with a value of 31° obtained from direct shear tests. It is recommended that further studies be undertaken to assess if interparticle frictional strength is an appropriate strength parameter for evaluation of the stability of structures founded on fibrous peat.

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Comparison of Mechanical Properties of Fiber-Reinforced Sand under Triaxial Compression and Direct Shear

Open Geosciences ◽

10.1515/geo-2015-0041 ◽

2015 ◽

Vol 7 (1) ◽

Cited By ~ 7

Author(s):

Reza Noorzad ◽

Seyed Taher Ghoreyshi Zarinkolaei

Keyword(s):

Shear Strength ◽

Axial Strain ◽

Triaxial Compression ◽

Polypropylene Fiber ◽

Triaxial Tests ◽

Direct Shear ◽

Test Results ◽

Peak Reduction ◽

Shear Tests ◽

Direct Shear Tests

AbstractThis research investigates the behavior of sand reinforced with polypropylene fiber. To do this, 40 direct shear tests and 40 triaxial tests were performed on the coastal beaches of Babolsar, a city in the North of Iran. The effect of parameters such as fiber content, length of fiber and normal or confining pressure on the behavior of Babolsar sand have been studied. In this study, four various fiber contents (0, 0.25, 0.5 and 1 percent), three different lengths of fiber (6, 12 and 18 mm) and four normal or confining pressures (50, 100, 200 and 400 kPa) have been employed. The test results show that fiber inclusion has a significant effect on the behavior of sand. In both direct shear and triaxial tests, the addition of fibers improved shear strength parameters (C, '), increased peak shear strength and axial strain at failure, and also limited the amount of post-peak reduction in shear resistance. The comparison of the test results revealed that due to better fiber orientation toward the direction of principal tensile strain in triaxial test as compared to direct shear tests, the fiber efficiency and its effect on soil behavior is much more significant in triaxial specimens.

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X-Ray Microtomography (μCT) as a Useful Tool for Visualization and Interpretation of Shear Strength Test Results

Studia Geotechnica et Mechanica ◽

10.2478/sgem-2014-0035 ◽

2015 ◽

Vol 36 (4) ◽

pp. 47-55 ◽

Cited By ~ 2

Author(s):

Damian Stefaniuk ◽

Matylda Tankiewicz ◽

Joanna Stróżyk

Keyword(s):

Shear Strength ◽

Shear Failure ◽

Triaxial Compression ◽

Soil Testing ◽

Geometrical Parameters ◽

Clayey Soils ◽

Test Results ◽

Strength Parameters ◽

X Ray ◽

Method Of Evaluation

Abstract The paper demonstrates the applicability of X-ray microtomography (ìCT) to analysis of the results of shear strength examinations of clayey soils. The method of X-ray three-dimensional imaging offers new possibilities in soil testing. The work focuses on a non-destructive method of evaluation of specimen quality used in shear tests and mechanical behavior of soil. The paper presents the results of examination of 4 selected clayey soils. Specimens prepared for the triaxial test have been scanned using ìCT before and after the triaxial compression tests. The shear strength parameters of the soils have been estimated. Changes in soil structure caused by compression and shear failure have been presented as visualizations of the samples tested. This allowed for improved interpretation and evaluation of soil strength parameters and recognition of pre-existing fissures and the exact mode of failure. Basic geometrical parameters have been determined for selected cross-sections of specimens after failure. The test results indicate the utility of the method applied in soil testing.

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Shear strength behaviour of sand-bentonite mixtures with pumice additivite under high temperature

E3S Web of Conferences ◽

10.1051/e3sconf/202020504004 ◽

2020 ◽

Vol 205 ◽

pp. 04004

Author(s):

Esra Güneri ◽

Yeliz Yükselen Aksoy

Keyword(s):

Shear Strength ◽

High Temperature ◽

Room Temperature ◽

Engineering Properties ◽

Direct Shear ◽

Test Results ◽

Soil Behavior ◽

Shear Tests ◽

Volume Deformation ◽

Direct Shear Tests

Depending on increase in the number and type of energy geostructures, studies on the change in soil behavior against heat increase becomes more important. The engineering properties such as permeability, volume deformation of surrounding soils around energy structures mustn’t alter in the presence of heat and thermal cycles. Pumice is a material used in many fields especially for thermal insulation. For that reason, pumice can be used for increasing the resistance of soils in the presence of heat. In this study, the shear strength behavior of sand-bentonite mixtures was investigated with pumice additive under high temperature. In the experiments, 10% and 20% pumice were added to 10% and 20% sand-bentonite mixtures and compaction, direct shear tests were conducted. The direct shear tests were performed both room temperature and under 80°C. The results have shown that the pumice additive increased the shear strength of sand-bentonite mixtures under high temperature when compared the test results under room temperature.

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Shear strength of bonded concrete-granite joints under constant normal stress conditions

E3S Web of Conferences ◽

10.1051/e3sconf/20199213014 ◽

2019 ◽

Vol 92 ◽

pp. 13014

Author(s):

Matthieu Briffaut ◽

Bassel El Merabi ◽

Frédéric Dufour ◽

Grégory Coubard

Keyword(s):

Shear Strength ◽

Normal Stress ◽

Roughness Parameter ◽

Stress Conditions ◽

Shear Behaviour ◽

Bonded Joints ◽

Test Results ◽

Direct Shear Tests ◽

Joint Surfaces ◽

Granite Samples

The shear behaviour of bonded concrete-granite joints under constant normal stress conditions is experimentally investigated in this paper. Concrete was prepared following standard mix used in pre-existing dams in France and poured on granite samples with a natural surface roughness. Before the direct shear tests, the joint surfaces were scanned by a laser profilometer to obtain the 3D morphology features. By analysing the shear test results, no direct correlations were found between the shear strength of bonded joints and classical roughness parameter.

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Mechanical behavior of compacted composite clays

Canadian Geotechnical Journal ◽

10.1139/t04-062 ◽

2004 ◽

Vol 41 (6) ◽

pp. 1152-1167 ◽

Cited By ~ 43

Author(s):

M K Jafari ◽

A Shafiee

Keyword(s):

Shear Strength ◽

Cyclic Loading ◽

Mechanical Behavior ◽

Pore Pressure ◽

Aggregate Size ◽

Core Material ◽

Main Body ◽

Test Results ◽

Aggregate Content ◽

Heterogeneous Matrix

Composite clay is a mixture of clay, as the main body, and aggregates, which are floating within the clayey matrix. The undrained behavior of composite clay in its natural or compacted state, e.g., core material of embankment dams, has great importance for geotechnical engineers. An extensive test program was conducted on kaolingravel and kaolinsand mixtures to investigate various effects of aggregates on the mechanical behavior of the mixtures during strain-controlled monotonic and cyclic loadings. Monotonic test results reveal that increasing the aggregate content leads to a gradual increase in shear strength. Meanwhile, when the aggregate content is raised, the pore pressure increases for both monotonic and cyclic loading. It is also found that the presence of aggregates within a cohesive matrix leads to formation of a heterogeneous matrix in the clayey part of composite clays. This heterogeneity in turn causes pore pressure to be increased with an increase in the aggregate content during both monotonic and cyclic loading. In addition, test results show that aggregate size does not influence mechanical behavior appreciably. The results of this experimental research program are presented and discussed in this paper.Key words: composite clay, aggregate, shear strength, pore pressure, heterogeneous matrix, embankment dam.

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Analisis Kestabilan Lereng Berdasarkan Kekuatan Geser Massa Batuan Terhadap Perubahan Kandungan Air Pada Tambang Batubara Di Area Blok Menyango

PROMINE ◽

10.33019/promine.v7i2.1645 ◽

2019 ◽

Vol 7 (2) ◽

pp. 71-77

Author(s):

Novandri Kusuma Wardana

Keyword(s):

Shear Strength ◽

Natural Condition ◽

Shear Failure ◽

Friction Angle ◽

Direct Shear ◽

Test Results ◽

Shear Tests ◽

Direct Shear Tests ◽

Wet Condition ◽

The Impact

Mining activities is commonly to work with the problem of stability of rock mass, then befordesaining mine’s slope should know rock shear strength parameters, such as cohesion (c) andinternal friction angle value ( . Beside those parameters, also needed to know the impact ofwater content to the rocks. The water content will effect rock’s shear strength, proof by the rockcondition which is ductile when it is dry and soft when it is wet. Based on test results was doneusing sandstone with laboratory scale of direct shear test were analyzed using mohr – coulomband patton criteria (1966). It is known that the cohesion (c) of sandstone decreased from 510,35kPa at natural condition down to 133,75 kPa at wet condition. The internal friction angle ( ) alsodecreased from 54,56° at natural condition down to 48,45° at wet condition. The reduction of theshear strength is caused by fragments and clay minerals characteristics which are so reactiveand very easy to absorb water so that the cohesion of the sandstone reduce the active normalstress so that working the shear stress required to cause the shear failure becomeweaker. From the results, it is also known that the shear surface roughness had a lot ofinfluence on the shear strength the normal stresses applied on the direct shear tests werevery low under 20% of UCS.

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