scholarly journals The Effect of Polymer-Fiber Stabilization on the Unconfined Compressive Strength and Shear Strength of Sand

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Jin Liu ◽  
Qiao Feng ◽  
Yong Wang ◽  
Yuxia Bai ◽  
Jihong Wei ◽  
...  
Keyword(s):  
Unconfined Compressive Strength ◽  
Direct Shear Test ◽  
Shear Test ◽  
Polypropylene Fiber ◽  
Organic Polymer ◽  
Test Results ◽  
Polymer Fiber ◽  
Compressive Test ◽  
Soil Stabilizer ◽  
Scanning Electron

The mixed soil stabilizer of polyurethane organic polymer and polypropylene fiber was used to reinforce sand. The unconfined compressive test and direct shear test were carried out to evaluate the effects of polymer-fiber reinforced sand. The different contents of polymer and fiber were selected for the tests. The test results indicated that polymer-fiber mixture can improve strongly the strength of sand. The presence of polyurethane organic polymer enhances sand structural stability and the best composition of polymer and fiber was 4% and 0.2–0.3% of dry sand, respectively. Based on the test results and images of scanning electron microscope (SEM), the reinforcement mechanism was analyzed. The research results can be considered as the reference for sand reinforced engineering.

Study on the Impact of Long-Term Immersion on the Shear Strength of Compacted Lime Stabilized Expansive Soils

2012 ◽  
Vol 238 ◽  
pp. 431-434
Author(s):  
Yun Dong ◽  
Wei Zhong He ◽  
Bao Tian Wang
Keyword(s):  
Shear Strength ◽  
Immersion Time ◽  
Direct Shear Test ◽  
Shear Test ◽  
Expansive Soils ◽  
Test Results ◽  
Slope Analysis ◽  
Normal Strength ◽  
The Impact

To offer or predict the shear strength of compacted lime stabilized expansive soils after long-term immersion for the slope analysis, the paper carried out direct shear test on the compacted stabilized expansive soils after different immersion time. The test results show that long-term immersion has significant impact on the shear strength of the lime stabilized expansive soils, the shear strength reduced sharply after soaking, but the shear strength tends to a stable value about 60%~70% normal strength while soaking is longer than 50 days. Logarithm model can well fitted the sketch of φ, c and immersion times within 50 days, which may be used to predict the shear strength of the stabilized expansive soils quickly.

The Strength of High-Temperature Ag–In Joints Produced Between Copper by Fluxless Low-Temperature Processes

2014 ◽  
Vol 136 (1) ◽  
Author(s):  
Yuan-Yun Wu ◽  
Chin C. Lee
Keyword(s):  
Solid Solution ◽  
Electron Microscope ◽  
Shear Test ◽  
Test Results ◽  
X Ray ◽  
Ductile Mode ◽  
Micron Size ◽  
Cu Substrates ◽  
Strength And Ductility ◽  
Scanning Electron

Two copper (Cu) substrates were bonded using silver (Ag) and indium (In) and annealed at 200–250 °C to convert the joints into the solid solution (Ag) for enhanced strength and ductility. Cu–Cu pair was chosen so that the samples break in the joint during shear test. The upper Cu was electroplated with 15 μm Ag. The lower Cu was plated with 15 μm Ag, followed by In and 0.1 μm Ag to inhibit indium oxidation. Two designs were implemented, using 8 μm and 5 μm In, respectively. The Cu substrates were bonded at 180 °C in 100 mTorr vacuum without flux. Afterwards, samples were annealed at 200 °C for 1000 h (first design) and at 250 °C for 350 h (second design), respectively. Scanning electron microscope with energy dispersive X-ray analysis (SEM and EDX) results indicate that the joint of the first design is an alloy of mostly (Ag) with micron-size Ag2In and (ζ) regions, and that of second design has converted to a single (Ag) phase. Shear test results show that the samples are very strong. The breaking forces far exceed requirements in MIL-STD-883 H standards. Fracture incurs inside the joint and is a mix of brittle and ductile modes or only ductile mode. The joint solidus temperatures are 600 °C and 900 °C for the first and second designs, respectively.

Study on Libyan Silt Property and Suggestions on its Application in Subgrade Construction

2014 ◽  
Vol 587-589 ◽  
pp. 1305-1310
Author(s):  
Ze Yu Zhang ◽  
Li Yun Peng ◽  
Jian Ye Wang ◽  
Abobakir Abdulali
Keyword(s):  
Mechanical Properties ◽  
Direct Shear Test ◽  
Shear Test ◽  
Physical And Mechanical Properties ◽  
Soil Improvement ◽  
Liquid Limit ◽  
Direct Shear ◽  
Test Results ◽  
Soil Slope ◽  
Capillary Water

The basic physical and mechanical properties of Libyan soil are analyzed through some experiments, including direct shear test, grading analysis test and compression test. According to the test results, the soil is named as low liquid limit silt featured by weak strength, high compressibility and permeability, which directly influences sub-grade stability, durability and pavement’s usability. In order to solve these problems, measures are discussed from two aspects, namely, soil improvement and construction method. The strength of the soil is apparently increased by the cement and lime adding, and the compressibility is decreased at the same time. And the rising height of capillary water reducing and protection forms for silt soil slope are also proved to be effective in the subgrade construction.

Effect of weathering on the compressibility and shear strength of a natural clay

2006 ◽  
Vol 43 (6) ◽  
pp. 618-625 ◽  
Author(s):  
Giovanni Gullà ◽  
Maria Clorinda Mandaglio ◽  
Nicola Moraci
Keyword(s):  
Shear Strength ◽  
Direct Shear Test ◽  
Shear Test ◽  
Direct Shear ◽  
Test Results ◽  
Natural Clay ◽  
Standard Equipment ◽  
Overconsolidated Clays ◽  
Weathering Process

In situ, seasonal changes expose soils to frequent wetting–drying–freezing–thawing cycles. Such processes can favour and trigger shallow instabilities controlled by the weathering process. This paper presents an experimental study carried out to investigate the effects of the weathering process, caused by the wetting–drying–freezing–thawing cycles, on the compressibility and shear strength of a natural clay. Several specimens were trimmed from block samples of overconsolidated clays taken from a slope in south Calabria, Italy. Specimens were subjected to wetting–drying–freezing–thawing cycles of different durations and then tested with standard equipment (oedometer and direct shear). Test results show that the wetting–drying–freezing–thawing cycles caused a change in the initial microstructure that produced a decrease in the compression index and an increase in the swelling index. Moreover, the direct shear test results show a decrease in the peak shear strength and demonstrate that a larger reduction occurs in the first month of weathering cycles. The intense cycles performed in the laboratory produced a decay of compressibility and a shear strength approaching reconstituted values. The conclusions are important when choosing the shear strength parameters required when studying shallow landsliding in clay slopes.Key words: weathered clay, structure, cycle of degradation, shallow instability.

scholarly journals Comparative Study in Method of Compaction by Consolidated Drained and Direct Shear Test

2020 ◽  
Vol 78 (2) ◽  
pp. 143-152
Author(s):  
Abdul Samad Abdul Rahman ◽  
N. Sidek ◽  
Juhaizad Ahmad ◽  
N. Hamzah ◽  
M. I. F. Rosli
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Triaxial Test ◽  
Direct Shear Test ◽  
Shear Test ◽  
Void Ratio ◽  
Direct Shear ◽  
Test Results ◽  
Stress Strain ◽  
Strain Behaviour

Soil compaction has been a common practice in the construction of highways, embankments, earth dams and other related structures where the condition of the soil is high in void ratio and therefore having a very low in bearing capacity. Therefore, the soil needs to be compacted in order to minimize the void ratio and in the same time would results in having a very high bearing capacity to sustain load. Nevertheless, only a few researches have been done to investigate the method of compaction using different energy on the behavior of shear strength by consolidated drained and direct shear test. In this research, the effect of different compaction in energy of 25 number of blows compared to 40 number of blows on the stress-strain behaviour of drained triaxial test has been done and findings of the data are to be compared with direct shear test. Results reveal that there is an increase in soil unit weight by using different energy in compaction with an increase of 5% from 1790 kg/m3 to 1880 kg/m3 for 25 and 40 number of blows respectively. However, the stress-strain behaviour of the specimens shows differently when compared between consolidated drained triaxial and direct shear test. The shear strength for direct shear-stress is at higher value compared to drained triaxial test. For drained triaxial test, results reveal that the effective friction angles are increase only about 1% from 37° to 38°. This is due to the soil particles rearranging itself with the different applied pressures thus eliminating the effects of different energy on the shear strength of the specimens. However, for direct shear test, the shear strength increases drastically from 29° to 32°. The increase of the shear strength is more likely influence by the soil particle arrangement due to the impact of the energy of the no of blows to the desired specimen.

Processing and Mechanical Properties of Porous Titanium-Niobium Shape Memory Alloy for Biomedical Applications

2007 ◽  
Vol 561-565 ◽  
pp. 1689-1692 ◽  
Author(s):  
Jian Yu Xiong ◽  
Yun Cang Li ◽  
Yasuo Yamada ◽  
Peter D. Hodgson ◽  
Cui E Wen
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Biomedical Applications ◽  
Elastic Moduli ◽  
Porous Titanium ◽  
Porous Structures ◽  
Test Results ◽  
Sintering Process ◽  
Compressive Test ◽  
Scanning Electron

Ti-26 at.%Nb (hereafter Ti-26Nb) alloy foams were fabricated by space-holder sintering process. The porous structures of the foams were characterized by scanning electron microscopy (SEM). The mechanical properties of the Ti-26Nb foam samples were investigated using compressive test. Results indicate that mechanical properties of Ti-26Nb foam samples are influenced by foam porosity. The plateau stresses and elastic moduli of the foams under compression decrease with the increase of their porosities. The plateau stresses and elastic moduli are measured to be from 10~200 MPa and 0.4~5.0 GPa for the Ti-26Nb foam samples with porosities ranged from 80~50 %, respectively.

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