scholarly journals Dynamic Properties of Granulated Rubber Using Different Laboratory Tests

Buildings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 186
Author(s):  
Ahmed Moussa ◽  
Hany El Naggar ◽  
Abouzar Sadrekarimi
Keyword(s):  
Shear Strain ◽  
Strain Amplitude ◽  
Simple Shear ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Shear Tests ◽  
Cyclic Triaxial ◽  
Scrap Tires ◽  
Direct Simple Shear ◽  
Shear Strain Amplitude

Due to the socio-environmental hazards arising from the stockpiling of disposed scrap tires, the necessity to utilize such material in civil construction and other applications is deemed mandatory. The lightweight of rubber and its high damping capacity are excellent properties of a geomaterial that could be used successfully in seismic isolation and vibration damping applications in civil construction. Scrap tires could be shredded into specific sizes, and their category and application depend on their particle size range. Thus, understanding the dynamic properties and behavior of shredded scrap tires under cyclic loading is of paramount importance. In this study, the dynamic characteristics of granulated rubbers (<12 mm) are investigated using cyclic triaxial and cyclic direct simple shear tests. The effect of using different testing techniques, i.e., cyclic triaxial test (CTT) and cyclic simple shear test (CSST), on the dynamic properties of granulated rubber material is further addressed. Undrained cyclic triaxial and constant-volume direct simple shear tests are conducted on granulated rubber samples under vertical consolidation stresses of 25, 50, 100 and 200 kPa at a frequency of 0.5 Hz. The shear strain amplitude is varied from 0.01% to 10%. Furthermore, the variations of shear modulus and damping ratio with shear strain amplitude are presented. In addition, the obtained dynamic properties from this study are compared with existing experimental data from the literature. It was found that the ranges of shear moduli of granulated rubber from the CTT and CSST are 278 to 2647 kPa and 85 to 2270 kPa, respectively. Moreover, the damping ratios obtained from CTT were higher than those from CSST at shear strains of less than 1%. The damping ratio of granulated rubber was also found to be independent of the vertical consolidation stress.

Shear Modulus and Damping Ratio of Gravel Material

2011 ◽  
Vol 105-107 ◽  
pp. 1426-1432 ◽  
Author(s):  
De Gao Zou ◽  
Tao Gong ◽  
Jing Mao Liu ◽  
Xian Jing Kong
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Strain Amplitude ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Dynamic Shear Modulus ◽  
Test Results ◽  
Dynamic Shear ◽  
Data Points ◽  
Shear Strain Amplitude

Two of the most important parameters in dynamic analysis involving soils are the dynamic shear modulus and the damping ratio. In this study, a series of tests were performed on gravels. For comparison, some other tests carried out by other researchers were also collected. The test results show that normalized shear modulus and damping ratio vary with the shear strain amplitude, (1) normalized shear modulus decreases with the increase of dynamic shear strain amplitude, and as the confining pressure increases, the test data points move from the low end toward the high end; (2) damping ratio increases with the increase of shear strain amplitude, damping ratio is dependent on confining pressure where an increase in confining pressure decreased damping ratio. According to the test results, a reference formula is proposed to evaluate the maximum dynamic shear modulus, the best-fit curve and standard deviation bounds for the range of data points are also proposed.

scholarly journals Empirical Formulas of Shear Modulus and Damping Ratio for Geopolymer-Stabilized Coarse-Grained Soils

2021 ◽  
Vol 9 ◽  
Author(s):  
Shengnian Wang ◽  
Xinqun Gao ◽  
Wei Ma ◽  
Guoyu Li ◽  
Chong Shi ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Strain Amplitude ◽  
Large Scale ◽  
Damping Ratio ◽  
Coarse Grained ◽  
Dynamic Shear Modulus ◽  
Empirical Formulas ◽  
Confining Pressures ◽  
Shear Strain Amplitude

The contribution of gravel fraction on the maximum shear modulus (Gmax), dynamic shear modulus ratio (G/Gmax), and damping ratio (λ) of cementitious coarse-grained soils has not been fully understood yet. Large-scale triaxial cyclic tests for geopolymer-stabilized coarse-grained soils (GSCGSs) were conducted with different volumetric block proportions (VBPs) under various confining pressures (CPs) for investigating their dynamic behaviors and energy dissipation mechanisms. Results indicate that the Gmax of GSCGS increases linearly with VBPs but nonlinearly with CP. High VBPs will probably result in a gentle decrease in G/Gmax and a rapid increase in normalized λ (λnor), while the opposite is the case for a high CP. With the shear strain amplitude being normalized, the G/Gmax and λnor are distributed in a narrow band with low dispersion and thus can be well-described by empirical functions of the normalized shear strain amplitude.

scholarly journals A Comparison between Simple Shear and Triaxial Tests for Evaluating the Variations of G and D with Matric Suction

2019 ◽  
Vol 92 ◽  
pp. 07010
Author(s):  
Kazem Fakharian ◽  
Danial Shirkavand ◽  
Manouchehr Hejazi
Keyword(s):  
Shear Strain ◽  
Simple Shear ◽  
Damping Ratio ◽  
Silica Sand ◽  
Triaxial Tests ◽  
Residual Water ◽  
Shear Tests ◽  
Confining Stress ◽  
Limit Value ◽  
Soil Dynamic

Shear modulus (G) and damping ratio (D) are both well known as principal soil dynamic parameters. In the present study, cyclic triaxial and simple shear tests are performed on Firuzkuh silica sand at various shear strain amplitudes using the developed testing devices and peripherals. It is well-understood that degrading curvature of G with shear strain appears in both triaxial and simple shear results. Nevertheless, mean confining stress has dissimilar effects in each of the two tests that does not provide comparable empirical correlations. It is noticed that the variations of G and D with suction stress in triaxial differs from those in simple shear. On the basis of cyclic simple shear results, the increase in suction pressure from zero to the end of transition zone in SWCC leads to increase in G values. In triaxial method, on the other hand, similar increase occurs only up to the inflection point in SWCC, starts reducing afterwards down to a limit value at residual water content. The damping ratio variations with shear strain are generally ascending despite local drops at the strain order of 0.1%, which has appeared in both triaxial and simple shear results.

scholarly journals Effects of granular shape on shear modulus and damping ratio of gravel

2019 ◽  
Vol 23 (1) ◽  
pp. 87-91
Author(s):  
Kai Cui ◽  
Hang Sheng
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Strain Amplitude ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Test Results ◽  
Grain Composition ◽  
Confining Pressures ◽  
Shear Strain Amplitude

The effects of the consolidation ratio, effective confining pressure, gravel content, and granule breakage on the shear modulus and damping ratio of gravel have been extensively researched in recent years. However, studies on the effect of the granular shape are rare. Thus, under different confining pressures, dynamic triaxial tests were performed on gravel specimens to investigate the effect of granular shape on the shear modulus and damping ratio of gravel specimens by using a multifunctional triaxial testing instrument. The samples consisted of two kinds of gravel with the same grain composition and relative density of 45%. The test results indicate that, when the confining pressure and shear strain amplitude exceed 300 kPa and 7×10-4, respectively, gravel with a round granular shape has a higher shear modulus compared to an angular shape. Conversely, when the shear strain amplitude exceeds 2×10-4, the damping ratio of angular gravel exceeds that of round granules.

scholarly journals The Influence of Apparatus Stiffness on the Results of Cyclic Direct Simple Shear Tests on Dense Sand

2020 ◽  
Vol 44 (5) ◽  
pp. 20190471
Author(s):  
M. Konstadinou ◽  
A. Bezuijen ◽  
G. Greeuw ◽  
C. Zwanenburg ◽  
H. M. Van Essen ◽  
...  
Keyword(s):  
Simple Shear ◽  
Shear Tests ◽  
Dense Sand ◽  
Direct Simple Shear

scholarly journals Characterization of the Dynamic Properties of Clay–Gravel Mixtures at Low Strain Level

2020 ◽  
Vol 12 (4) ◽  
pp. 1616 ◽  
Author(s):  
Xianwen Huang ◽  
Aizhao Zhou ◽  
Wei Wang ◽  
Pengming Jiang
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Mechanical Performance ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Strain Level ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Gravel Content

In order to support the dynamic design of subgrade filling engineering, an experiment on the dynamic shear modulus (G) and damping ratio (D) of clay–gravel mixtures (CGMs) was carried out. Forty-two groups of resonant column tests were conducted to explore the effects of gravel content (0%, 10%, 20%, 30%, 40%, 50%, and 60%, which was the mass ratio of gravel to clay), gravel shape (round and angular gravels), and confining pressure (100, 200, and 300 kPa) on the dynamic shear modulus, and damping ratio of CGMs under the same compacting power. The test results showed that, with the increase of gravel content, the maximum dynamic shear modulus of CGMs increases, the referent shear strain increases linearly, and the minimum and maximum damping ratios decrease gradually. In CGMs with round gravels, the maximum dynamic shear modulus and the maximum damping ratio are greater, and the referent shear strain and the minimum damping ratio are smaller, compared to those with angular gravels. With the increase of confining pressure, the maximum dynamic shear modulus and the referent shear strain increase nonlinearly, while the minimum and maximum damping ratios decrease nonlinearly. The predicting equation for the dynamic shear modulus and the damping ratio of CGMs when considering confining pressure, gravel content, and shape was established. The results of this research may put forward a solid foundation for engineering design considering low-strain-level mechanical performance.

Cyclic Simple Shear Apparatus for Low-Strain Soil Tests

1996 ◽  
Vol 1548 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Heather J. Miller ◽  
Pedro de Alba ◽  
Kenneth C. Baldwin
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Simple Shear ◽  
Recovery Period ◽  
Triaxial Tests ◽  
Cyclic Shear ◽  
Aging Period ◽  
Direct Simple Shear ◽  
Fabric Evolution ◽  
Excess Pore Pressures

A testing system has been developed to study the behavior of saturated sand under low-level cyclic shearing strains. The system has been used to determine threshold shear strain levels for fabric destruction in sand aged for different time periods. The system includes a special soil chamber and a direct simple shear (DSS) machine. To impose very small shearing strains, the DSS machine was designed to apply and measure horizontal deformations as small as 0.0005 mm (2 × 10−5 inches). Data obtained to date support the results of previous investigators who performed triaxial tests on freshly deposited samples, indicating a threshold cyclic shear strain level of approximately 0.01 percent. At strains in excess of those levels, destruction of the sand fabric occurred, as evidenced by a reduction in shear modulus at low strain levels. Subsequent modest increases in shear modulus were observed after the specimens were allowed to recover for 24 hours and then tested again. During the recovery period, drainage valves were left open to allow for dissipation of excess pore pressures and for potential consolidation during the short aging period. The DSS system was found to work well for low strain measurements. Furthermore, since shear strains are measured directly under DSS conditions (as opposed to triaxial conditions), the DSS system shows much promise as a device for studying parameters that may influence threshold shear strain levels and fabric evolution and destruction in sands.

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