scholarly journals Large-Scale Direct Shear Test on Tire Slice Reinforced Crushed Concrete Particles

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Qiang Ma ◽  
Hang Shu ◽  
Jia Mou ◽  
Lihua Li ◽  
Zhenyi Zheng
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Shear Rate ◽  
Volume Content ◽  
Large Scale ◽  
Friction Angle ◽  
Vertical Load ◽  
Reinforcement Effect ◽  
Crushed Concrete ◽  
Peak Shear Stress

In order to study the mechanical properties of tire slices reinforced crushed concrete particles, a series of shear tests were carried out under the conditions of different vertical loads, different tire volume contents, and different shear rates. The test results show that the addition of tire slices can increase the internal friction angle and cohesion of concrete particles, therefore increase the shear strength of crushed concrete particles. The peak shear stress increases with the increase of vertical load. However, with the increase of the tire volume content, the reinforcement effect of the tire slices first increases and then decreases, and the effect is best when the tire volume content is 4%. Under the vertical load of 60 kPa, the reinforcement effect of 4% tire volume content is the best, and the peak shear stress increases by 46.53%. Additionally, the shear rate has a little effect on the peak shear stress. The larger the shear rate is, the smaller the shear displacement is and the faster the shear strength decreases. The smaller the shear rate is, the more gently the shear strength decreases.

Characterization of Shear Strength and Interface Friction of Organic Soil

2020 ◽  
Vol 857 ◽  
pp. 203-211
Author(s):  
Majid Hamed ◽  
Waleed S. Sidik ◽  
Hanifi Canakci ◽  
Fatih Celik ◽  
Romel N. Georgees
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Internal Friction ◽  
Moisture Content ◽  
Water Content ◽  
Friction Angle ◽  
Structural Materials ◽  
Organic Soil ◽  
Internal Friction Angle ◽  
Interface Friction

This study was undertaken to investigate some specific problems that limit a safe design and construction of structures on problematic soils. An experimental study was carried out to examine the influence of loading rate and moisture content on shear strength of organic soil. Influece of moisture content on interface friction between organic soil and structural materials was also attempted. A commonly used soil in Iraq was prepared at varying moisture contents of 39%, 57% and 75%. The experimental results showed that the increase in water content will decrease the shear stress and the internal friction angle. An increase of the shearing rate was found to decrease the shear stress and internal friction angle for all percetanges of water contents. Further, direct shear tests were carried out to detect the interface shear stress behavior between organic soil and structural materials. The results revealed that the increase in water content was shown to have significant negetavie effects on the interface internal friction and angle shear strength.

scholarly journals Determining the Shear Strength Properties of a Soil-geogrid Interface Using a Large-scale Direct Shear Test Apparatus

2020 ◽  
Author(s):  
Jakub Stacho ◽  
Monika Sulovska ◽  
Ivan Slavik
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Large Scale ◽  
Direct Shear Test ◽  
Shear Test ◽  
Strength Properties ◽  
Coarse Grained ◽  
Direct Shear ◽  
Test Apparatus ◽  
Fine Gravel

The paper deals with the laboratory testing of coarse-grained soils that are reinforced using a geogrid. The shear strength properties were determined using a large-scale direct shear test apparatus. The tests were executed on original as well as on reinforced soil, when the geogrid was placed on a sliding surface, which permitted determining the shear strength properties of the soil-geogrid interface. The aim of the tests was to determine the interface shear strength coefficient α, which represents the ratio of the shear strength of the soil-geogrid interface to the unreinforced soil. The tests were executed on 3 samples of coarse-grained materials, i.e., poorly graded sand, poorly graded fine gravel and poorly graded medium gravel. Two types of geogrids were tested, i.e., a woven polyester geogrid and a stiff polypropylene geogrid. The results of the laboratory tests on the medium gravel showed that the reduction coefficient α reached higher values in the case of the stiff polypropylene geogrid. In the cases of the fine gravel and sand, the values of the interface coefficient α were similar to each other. The shear strength of the interface was reduced or was similar to the shear strength of unreinforced soil in a peak shear stress state, but significantly increased with horizontal deformations, especially for the fine gravel and sand. The largest value of the coefficient α was measured in the critical shear stress state. Based on the results of the testing, a correlation which allows for determining the optimal grain size distribution was obtained.

scholarly journals Large-Scale Direct Shear Test on Scrap Tire Strip Reinforced Brick Powder

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Qiang Ma ◽  
Qian Deng ◽  
Jia Mou ◽  
Shuo Yang ◽  
Xu Zhang
Keyword(s):  
Shear Strength ◽  
Large Scale ◽  
Friction Angle ◽  
Vertical Displacement ◽  
Direct Shear ◽  
Peak Shear Strength ◽  
Scrap Tire ◽  
Volume Percentage ◽  
Optimal Dimension ◽  
Brick Powder

In order to clear the shear mechanism of the scrap tire strips reinforced brick powder, a series of large-scale direct shear tests were carried out on the pure brick powder and reinforced brick powder. The scrap tire strips with 50 mm in length, 5 mm in thickness, and 10 mm, 30 mm, and 50 mm in width were put into the brick powder with volume percentages of 2%, 6%, and 10% as reinforcement, respectively. The results show that the internal friction angle and cohesion increase by adding scrap tire strips into brick powder. The peak shear strength of reinforced brick powder initially decreases, thereafter increases and finally decreases with the increase of volume percentage of the scrap tire strips. And the peak shear strength increases in the initial stage and then decreases with the increase of the scrap tire strips dimension. The optimal dimension and volume percentage of the scrap tire strips are 50 mm × 30 mm × 5 mm and 6%, respectively. In addition, the scrap tire strips provide constraints to restrict the vertical displacement of integral reinforced brick powder, and relative to the pure brick powder, the larger the vertical load is, the greater the decrease of vertical displacement is.

scholarly journals Shear Strength and Pull-Out Response of Tire Shred-Sand Mixture Reinforced with Deformed Steel Bars

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Beenish Jehan Khan ◽  
Irshad Ahmad ◽  
Hassan Nasir ◽  
Abdullah Abdullah ◽  
Qazi Khawar Gohar
Keyword(s):  
Shear Strength ◽  
Large Scale ◽  
Friction Angle ◽  
Sand Mixture ◽  
Strain Behavior ◽  
Backfill Material ◽  
Pull Out ◽  
Tire Shreds ◽  
Steel Bars ◽  
Different Diameters

The use of scrap tires in various engineering applications has been extensively explored. The present study has the following aim: to evaluate the suitability of tire-sand mixtures as backfill material based on its shear strength. To achieve this objective, modified Proctor compaction tests were performed on tire shred-sand mixture with mixing proportions by weight of tire shreds and sand (0/100, 20/80, 30/70, and 40/60) using different sizes of tire shreds (50 mm, 75 mm, and 100 mm). Based on the results of the modified Proctor compaction test, the two mixing proportions, i.e., tire shred/sand, 20/80 and 30/70, respectively, were selected. Large-scale direct shear test indicated higher internal friction angle and cohesion values for tire shred-sand mixtures (30/70) with 100 mm tire size (38.5° and 19 kPa) as compared with sand-only backfill material (30.9° and 0 kPa). Based on stress-strain behavior plots, it was indicated that the inclusion of tire shreds imparts ductility to backfill mixtures. To achieve the second objective, the pull-out tests were performed with deformed steel bars of two different diameters (12.7 mm and 15.8 mm) embedded in various backfill mixtures prepared with tire shreds of three different sizes (50, 75, and 100 mm). The pull-out test result indicated that the deformed steel bars exhibit higher pull-out resistance in tire shred-sand mixtures (9.9 kN/m) compared with sand-only backfill material (4.1 kN/m).

scholarly journals Root Tensile Resistance of Selected Pennisetum Species and Shear Strength of Root-Permeated Soil

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Afaff Emhemed Ettbeb ◽  
Zulfahmi Ali Rahman ◽  
Wan Mohd Razi Idris ◽  
Jumaat Adam ◽  
S. Abd. Rahim ◽  
...  
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Tensile Force ◽  
Mineral Fertilizer ◽  
Tensile Tests ◽  
Root Diameter ◽  
Slope Instability ◽  
Root Reinforcement ◽  
Significant Relationships ◽  
Peak Shear Stress

It is widely recognized that vegetation plays a significant role in contrasting slope instability through the root reinforcement. The main objectives of this paper are to evaluate the root tensile of selected Pennisetum species, namely, P. pedicellatum (PPd) and P. polystachion (PPl), and to determine the soil shear strength of root-permeated soil from these species. The selected species were initially planted in the polybags using the hydroseeding technique. A mineral fertilizer of NPK ratio 10 : 8 : 10 was adopted in the hydroseeding mixture. Routine watering program was applied twice a day throughout growth observation for six months. Four replications were prepared for each species including a set of control polybags, which contained only soil for reference and comparison. The results of root tensile tests revealed the significant relationships between root diameter and tensile force. In comparison, the PPl was still indicated by higher values of root tensile force than PPd. The presence of roots clearly has contributed to the shear stress of root-permeated soils. The root density based on root biomass measurement attributed to the higher value of peak shear stress as achieved by PPl than PPd. The combined effects of root tensile and the soil shear strengths of this selected species can be used as biological materials in slope protection against erosion.

scholarly journals Shear Testing of the Interfacial Friction Between an HDPE Geomembrane and Solid Waste

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1672
Author(s):  
Luming Zhou ◽  
Zhende Zhu ◽  
Zhenpeng Yu ◽  
Cong Zhang
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Solid Waste ◽  
Rough Surface ◽  
Interfacial Shear Strength ◽  
Friction Angle ◽  
Interfacial Shear ◽  
Solid Wastes ◽  
Interfacial Friction ◽  
Industrial Solid Waste

High-density polyethylene (HDPE) geomembrane is often used as an anti-seepage material in domestic and industrial solid waste landfills. To study the interfacial shear strength between the HDPE anti-seepage geomembrane and various solid wastes, we performed direct shear tests on the contact interface between nine types of industrial solid waste or soil (desulfurization gypsum, fly ash, red mud, mercury slag, lead-zinc slag, manganese slag, silica fume, clay and sand) and a geomembrane with a smooth or rough surface in Guizhou Province, China. Friction strength parameters like the interfacial friction angle and the apparent cohesion between the HDPE geomembrane and various solid wastes were measured to analyze the shear strength of the interface between a geomembrane with either a smooth or a rough surface and various solid wastes. The interfacial shear stress between the HDPE geomembrane and the industrial solid waste increased with shear displacement and the slope of the stress-displacement curve decreased gradually. When shear displacement increased to a certain range, the shear stress at the interface remained unchanged. The interfacial shear strength between the geomembrane with a rough surface and the solid waste was higher than for the geomembrane with a smooth surface. Consequentially, the interfacial friction angle for the geomembrane with a rough surface was larger. The geomembrane with a rough surface had a better shear resistance and the shear characteristics fully developed when it was in full contact with the solid waste.

scholarly journals Triaxial Shear Test on Hydrochloric Acid-Contaminated Clay Treated by Lime, Crushed Concrete, and Super Absorbent Polymer

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Fang Tong ◽  
Qiang Ma ◽  
Xing Hu
Keyword(s):  
Shear Strength ◽  
Hydrochloric Acid ◽  
Internal Friction ◽  
Acid Concentration ◽  
Friction Angle ◽  
Double Electric Layer ◽  
Internal Friction Angle ◽  
Engineering Practice ◽  
Hydrochloric Acid Concentration ◽  
Crushed Concrete

Acid pollution weakens the bearing capacity of subgrade, and discarded concrete occupies land. The mechanical properties of hydrochloric acid-contaminated clay were investigated by triaxial consolidation undrained tests. Also, the theory of diffusion double electric layer was employed to explain the change principle of cohesion and compression characteristics of hydrochloric acid-contaminated clay. In addtion, the curing effects of lime, crushed concrete, and SAP on the shear strength of hydrochloric acid-contaminated clay were compared. The triaxial test results show that cohesion decreased with the increase of hydrochloric acid concentration. The internal friction angle firstly increased and then decreased, and the change of internal friction angle was less affected by acid concentration. The curing effect of crushed concrete was similar to that of lime, which was better than lime. SAP could only improve the cohesion of the hydrochloric acid-contaminated clay; the internal friction angle decreased significantly; the three kinds of curing materials could significantly improve the cohesion of acid-contaminated clay to be higher than the natural clay, improving the shear strength to a certain extent. Additionally, the theory analysis illustrated that due to the change in the thickness of the diffusion layer between the clay particles, the van der Waals force between the particles changed, and the colloidal formation of the micelles led to changes in cohesion. The study can provide references to the treatment of contaminated soil in engineering practice.

scholarly journals Artificial Ground Freezing Impact on Shear Strength and Microstructure of Granite Residual Soil Under an Extremely Low Temperature

2021 ◽  
Vol 9 ◽  
Author(s):  
Ran An ◽  
Xianwei Zhang ◽  
Lingwei Kong ◽  
Jianwu Gong ◽  
Xuewen Lei
Keyword(s):  
Shear Strength ◽  
Low Temperature ◽  
Magnetic Resonance Image ◽  
Large Scale ◽  
Friction Angle ◽  
Treatment Temperature ◽  
Residual Soil ◽  
Ground Freezing ◽  
Artificial Ground Freezing ◽  
Granite Residual Soil

The Artificial Ground Freezing (AGF) method, which is widely used in tunnel excavations, significantly affects the properties of geotechnical materials in frozen walls under extremely low temperatures. In order to simulate the AGF process, the freezing treatment with a temperature of −30°C and thawing treatment temperature of 25°C were performed on natural specimens of granite residual soil (GRS). Subsequently, triaxial (TRX) tests were conducted to evaluate mechanical properties and Nuclear Magnetic Resonance Image (NMRI) tests were applied to detect pore distributions of GRS. To clarify variations of microstructure after freezing-thawing, the relaxation time (T2) distribution curves and T2-weighted images from NMRI results were thoroughly analyzed from the perspective of quantization and visualization. Results show that the shear strength as well as the cohesion of GRS are reduced sharply by the AGF process, while the internal friction angle decreases gently. The pore size distribution (PSD) converted from the T2 curve is constituted of two different peaks, corresponding to micro-pores with diameters from 0.1 to 10 µm and macro-pores with diameters from 10 to 1,000 µm. Under the AGF impact, the expansion in macro-pores and shrinkage in micro-pores simultaneously exist in the specimen, which was verified from a visualized perspective by T2-weighted images. The frost heaving damage on shear strength is attributed to the microstructural disturbance caused by the presence of large-scale pores and uneven deformations in GRS, which is subjected to the AGF impact under an extremely low temperature.

scholarly journals Clayey Soil Strength Improvement by Using Alkali Activated Slag Reinforcing

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1076
Author(s):  
Darius Žurinskas ◽  
Danutė Vaičiukynienė ◽  
Gediminas Stelmokaitis ◽  
Viktoras Doroševas
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Clayey Soil ◽  
Fluorescence Analysis ◽  
Friction Angle ◽  
Soil Strength ◽  
Alkali Activated Slag ◽  
X Ray ◽  
Activated Slag ◽  
Alkali Activated

There are many studies related to using alkali activated binders for the improvement of clayey soil mechanical properties. In this study, alkali activated slag (AAS) for the improvement of clayey soil strength was used and it reinforced the clay. This paper presents results of an investigation on the utilization of ground-granulated blast-furnace slag in the reinforcement of clay soils. Therefore, significant cost savings could be achieved by using alkali activated slag as binding material. These samples were analyzed by X-Ray fluorescence analysis (XRF), X-Ray diffraction (XRD), scanning electron microscopy (SEM) and strength tests after the curing. The clay samples reinforced with AAS showed higher shear stress, cohesion and internal friction angle compared with the samples without reinforcement. The highest shear strength was achieved by using the highest amount of AAS (30%). This shear stress of the unreinforced clay samples could be increased from 63.2 to 137.4 kPa (117.4%) and from 123.2 to 257.4 kPa (108.9%) when the normal stress value of 100 and 500 kPa was used, respectively. The increase in shear strength is closely related to the compact contact zone between AAS and clay. Moreover, the new formed cementitious compounds of AAS had a positive influence on the shear strength of samples as well.

scholarly journals Experimental Studies on Interfacial Shear Characteristics between Polypropylene Woven Fabrics

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3649
Author(s):  
Fu Yi ◽  
Hui Li ◽  
Jia Zhang ◽  
Xutong Jiang ◽  
Maocheng Guan
Keyword(s):  
Shear Strength ◽  
Sliding Friction ◽  
Friction Angle ◽  
Woven Fabrics ◽  
Interfacial Shear ◽  
Warp Yarn ◽  
Peak Displacement ◽  
Pull Out ◽  
Peak Shear Stress ◽  
Shear Characteristics

Geotextile tubes are used in dam construction because fine tailings are difficult to use. The shear characteristics of geotextile tubes during dam operation are closely related to those of the materials used to construct the tubes. Pull-out tests can accurately reflect the interfacial shear characteristics between geosynthetics in practice, so pull-out tests were carried out for different interfacial types of polypropylene woven fabrics under dry and wet states. The effects of the type of interface and dry-wet states on the interfacial shear characteristics were investigated, and the impact mechanisms were also discussed. The results indicated that P-type interfaces (the warp yarn on the interface is parallel to the pulling direction) tended to harden. However, PTP-type (the warp yarn on the interface is perpendicular to each other) and T-type (the weft yarn on the interface is parallel to the pulling direction) interfaces softened first and then tended to plateau after reaching peak shear stress, and softening became more obvious at higher normal stresses. The displacement corresponding to peak shear stress (referred to as “peak displacement” in this paper) of interfaces was positively correlated with the normal stress, and the wet state reduced the interfacial peak displacement. For different types of interfaces, the peak displacement of the T-type interface was the largest, followed by PTP-type and P-type. Interfacial shear characteristics conformed to Mohr–Coulomb strength theory and, compared with quasi-cohesion values ranging from 1.334 to 3.606 kPa, the quasi-friction angle significantly contributed to the interfacial shear strength. The quasi-friction angle of the interface was composed of a sliding friction angle and an occlusal friction angle. The shear strength of the interface was more sensitive to the interface types than whether they were in the dry or wet state. For different types of interfaces and dry-wet states, the change in the interfacial shear strength is respectively affected by the occlusal friction angle and the sliding friction angle on the interface.

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