Effect of Chemical Composition of Fine Aggregate on the Frictional Behavior of Concrete–Soil Interface under Sulfuric Acid Environment

Through direct shear tests, this paper aimed to research the effect of fine marble aggregate on the shear strength and fractal dimension of the interface between soil and concrete corroded by sulfuric acid. More realistic concrete rough surfaces than the artificially roughened surfaces were formed by immersing four concrete plates in plastic buckets filled with sulfuric acid for different periods of time. The sand was adopted to imitate the soil. 3D laser scanner was employed to obtain the digital shapes of concrete plates subjected to sulfuric acid, and the rough surfaces were evaluated by fractal dimension. Large direct shear experiments were performed to obtain the curves of the interface shear stress and shear displacement between sand and corroded concrete plate. The method of data fitting was adopted to calculate the parameters of shear strength (i.e., friction angle and the cohesive) and the parameters of the Clough–Duncan hyperbolic model. The results indicated that as the corrosion days increased, the surface of the concrete plate became rougher, the surface fractal dimensions of the concrete corroded by sulfuric acid became bigger, and the interface friction angle became greater. The friction angle of the interface and the fractal dimensions of the surface of the concrete plate containing crushed gravel and marble sand were smaller than that of the concrete plate containing crushed gravel and river sand.

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Quantitative Analysis of the Relationship Between Shear Strength and Fractal Dimension of Solidified Dredger Fill with Different Fly Ash Content Under Monotonic Shear

Polish Maritime Research ◽

10.2478/pomr-2018-0084 ◽

2018 ◽

Vol 25 (s2) ◽

pp. 132-138 ◽

Cited By ~ 2

Author(s):

Yang Shuai ◽

Liu Wenbai ◽

Liu Hongwei

Keyword(s):

Shear Strength ◽

Fractal Dimension ◽

Fly Ash ◽

Particle Surface ◽

Fractal Dimensions ◽

Friction Angle ◽

Ash Content ◽

Strength Index ◽

Dredger Fill ◽

The Relationship

Abstract The dredger fill of Shanghai Hengsha Island Dongtan is solidified by curing agents with different fly ash content, and the shear strength index of solidified dredger fill is measured by the direct shear test. The microscopic images of solidified dredger fill are obtained by using SEM. The microscopic images are processed and analyzed by using IPP, and the fractal dimension including particle size fractal dimension Dps, aperture fractal dimension Dbs and particle surface fractal dimension Dpr is calculated by fractal theory. The quantitative analysis of the relationship between shear strength index and fractal dimension of solidified dredger fill is done. The research results show that the internal friction angle and the cohesion are closely related to the fly ash content λ and the curing period T, and the addition of fly ash can improve the effect of curing agent; There is no obvious linear relationship between the internal friction angle and the three fractal dimensions; The smaller particle surface fractal dimension Dpr and particle size fractal dimension Dps, the larger aperture fractal dimension Dbs, the greater the cohesion, and the cohesion has a good linear relationship with three fractal dimensions, and the correlation coefficient R2 is above 0.91.

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Influence of Structural Plane Microscopic Parameters on Direct Shear Strength

Advances in Civil Engineering ◽

10.1155/2018/9178140 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Yanhui Cheng ◽

Weijun Yang ◽

Dongliang He

Keyword(s):

Particle Size ◽

Shear Strength ◽

Internal Friction ◽

Direct Shear Test ◽

Shear Test ◽

Friction Angle ◽

Internal Friction Angle ◽

Direct Shear ◽

Stiffness Ratio ◽

Structural Plane

Structural plane is a key factor in controlling the stability of rock mass engineering. To study the influence of structural plane microscopic parameters on direct shear strength, this paper established the direct shear mechanical model of the structural plane by using the discrete element code PFC2D. From the mesoscopic perspective, the research on the direct shear test for structural plane has been conducted. The bonding strength and friction coefficient of the structural plane are investigated, and the effect of mesoscopic parameters on the shear mechanical behavior of the structural plane has been analyzed. The results show that the internal friction angle φ of the structural plane decreases with the increase of particle contact stiffness ratio. However, the change range of cohesion is small. The internal friction angle decreases first and then increases with the increase of parallel bond stiffness ratio. The influence of particle contact modulus EC on cohesion c is relatively small. The internal friction angle obtained by the direct shear test is larger than that obtained by the triaxial compression test. Parallel bond elastic modulus has a stronger impact on friction angle φ than that on cohesion c. Under the same normal stress conditions, the shear strength of the specimens increases with particle size. The shear strength of the specimen gradually decreases with the increase of the particle size ratio.

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Study on Water Characteristic Curve and Shear Characteristics of Typical Unsaturated Silty Clay in Shaoxing

Geofluids ◽

10.1155/2021/5510535 ◽

2021 ◽

Vol 2021 ◽

pp. 1-15

Author(s):

Ruiqian Wu ◽

Youzhi Tang ◽

Shaohe Li ◽

Wei Wang ◽

Ping Jiang ◽

...

Keyword(s):

Shear Strength ◽

Internal Friction ◽

Unsaturated Soil ◽

Direct Shear Test ◽

Shear Test ◽

Characteristic Curve ◽

Friction Angle ◽

Matric Suction ◽

Silty Clay ◽

Direct Shear

In order to probe into one simplified method to predict the shear strength of Shaoxing unsaturated silty clay, the test method combining unsaturated soil consolidation instrument and conventional direct shear instrument is used to study the shear strength, and the method is compared and verified with the results of equal suction direct shear test. The research results show that the soil water characteristic curve fitted by the measured data points and VG model has obvious stage characteristics in the range of 0~38 kPa, 38~910 kPa, and 910~10000 kPa. The shear strength of unsaturated soil measured by consolidation meter combined with conventional direct shear test is in good agreement with that measured by equal suction direct shear test in the range of 0~500 kPa. The results show that the shear strength, total cohesion, and effective internal friction angle of soil increase slightly with the increase of matric suction in the range of 0~38 kPa. When the matric suction increases from 38 kPa to 500 kPa, the shear strength and total cohesion force of the soil have similar stage characteristics with the SWCC, which first increases and then tends to be stable, while the effective internal friction angle changes slightly. Finally, taking the air-entry value as the demarcation point, an improved model of unsaturated shear strength is proposed by analyzing the error value. Compared with the measured value, the absolute value of relative error is basically kept in the range of 5%~10%, which is close to the measured value.

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Uncompacted Void Content of Fine Aggregate as Quality Indicator of Materials Used in Superpave Mixtures

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1723-05 ◽

2000 ◽

Vol 1723 (1) ◽

pp. 37-44 ◽

Cited By ~ 4

Author(s):

Jose Leomar Fernandes ◽

Reynaldo Roque ◽

Mang Tia ◽

Lorenzo Casanova

Keyword(s):

Shear Strength ◽

Microscopic Analysis ◽

Test Methods ◽

Standard Test ◽

Design System ◽

Void Content ◽

Fine Aggregate ◽

Direct Shear ◽

Lower Shear ◽

Fine Aggregates

The uncompacted void content of fine aggregate, or fine aggregate angularity (FAA), was introduced in the Superpave mixture design system to screen smooth or rounded fine aggregates that may result in mixtures with low rutting resistance. The assumption is that fine aggregates with lower FAA values have lower shear strength (internal friction) and lower resistance to rutting. Continued implementation and evaluation of the Superpave system has led to numerous questions regarding the validity of this assumption and of the use of the FAA test in general. Nine fine aggregates were used to evaluate the FAA test and to determine whether it was a reliable indicator of fine aggregate shear strength. FAA tests were performed using three gradations and the three standard test methods (A, B, and C). Microscopic analysis was conducted to obtain independent visual measures of angularity and texture. Direct shear tests were performed at four confining stresses to determine shear strength parameters. Results indicated that FAA values were related to visual measures of texture and angularity. However, although FAA value contributed to shear strength, it appeared that other factors such as toughness, gradation, and packing characteristics of the fine aggregate overshadow its effect. For the fine aggregates tested, the FAA test rejected aggregates with high shear strength and accepted aggregates with low shear strength. It was concluded that FAA values alone may not be adequate to assess shear resistance of fine aggregate. Direct shear strength may be a better parameter, but additional work is required to evaluate its validity and feasibility.

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

Advances in Civil Engineering ◽

10.1155/2019/6046037 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11 ◽

Cited By ~ 3

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.

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Direct Shear Strength of Clay Reinforced with Coir Fiber

UKaRsT ◽

10.30737/ukarst.v4i2.1020 ◽

2020 ◽

Vol 4 (2) ◽

pp. 151

Author(s):

Anita Widianti ◽

Willis Diana ◽

Maratul Hasana

Keyword(s):

Shear Strength ◽

Dry Weight ◽

Friction Angle ◽

Strength Test ◽

Fiber Content ◽

High Plasticity ◽

Coir Fiber ◽

Direct Shear ◽

Maximum Increase ◽

Shear Strength Test

Indonesia is the largest coconut producing country in the world. However, the resulting coir waste is still rarely used for structural materials. This research studied the effect of random inclusion of coir fiber on the shear strength of clay with high plasticity. The carried test in this study is a direct shear strength test. The fiber content variations used are 0%, 0.25%, 0.50%, 0.75%, and 1% of the dry weight of the mixture with a fiber length of between 30 mm to 50 mm. The results show that the reinforcement of coir fiber can increase the cohesion and friction angle. The maximum increase in cohesion value was obtained at fiber content of 0.75%, which was 39.66%. The increase in the value of the friction angle was obtained at 1% fiber content, which was 46.67%. The optimum coir fiber content was achieved at the fiber content of 0.75%. With this content, the value of the shear strength reaches its maximum with an increase of 39.4% at a normal stress of 8.071 kPa.

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Research on Direct Shear Strength Characteristics of Mechanically Biologically Treated Waste

10.21203/rs.3.rs-207864/v1 ◽

2021 ◽

Author(s):

Zhenying Zhang ◽

Jiahe Zhang ◽

Qiaona Wang ◽

Min Wang ◽

Chengyu Nie

Keyword(s):

Shear Strength ◽

Test Data ◽

Peak Stress ◽

Friction Angle ◽

Treatment Method ◽

Strength Characteristics ◽

Direct Shear ◽

Horizontal Shear ◽

Stability Calculation ◽

Shearing Rate

Abstract Mechanically biologically treated (MBT) waste has significant characteristics such as high stability and low moisture content, which can reduce water, soil, and gas pollution in subsequent treatments. This pre-treatment method is environmentally friendly and sustainable, and has become a popular research topic in the field of environmental geotechnical engineering. Using a direct shear test apparatus and five shearing rates (0.25, 1, 5, 10, and 20 mm/min), the shear strength characteristics of MBT waste at the Hangzhou Tianziling (HT) Landfill were studied. The results indicate: (1). With the increase in horizontal shear displacement, the shear stress of MBT waste gradually increases without a peak stress phenomenon, which is a displacement hardening curve; (2). The shear strength increased with an increase in the shearing displacement rate, and the sensitivity coefficient was 0.64–2.66. (3). The shear strength, shearing rate, and normal stress correlation model are established, and the model has a high degree of fit with the overall experimental data; (4). Cohesion (c), internal friction angle (φ), and the logarithm of the shearing rate are linear; (5). The range of c of MBT waste is 22.32–39.51 kPa, and φ is 64.24–.68.52°. Meanwhile, the test data are compared with the test data in the literature, and the shear characteristics of HT-MBT waste are discussed. The research results of this study can provide a reference for the stability calculation of MBT landfills.

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Determination of the Effect of Soil Particle Size Distribution on the Shear Behavior of Sand

Journal of Advanced Engineering and Computation ◽

10.25073/jaec.202152.331 ◽

2021 ◽

Vol 5 (2) ◽

pp. 125

Author(s):

Mohammad Afrazi ◽

Mahmoud Yazdani

Keyword(s):

Particle Size ◽

Shear Strength ◽

Direct Shear Test ◽

Shear Test ◽

Friction Angle ◽

Particle Sizes ◽

Direct Shear ◽

Shear Tests ◽

Direct Shear Tests

Many geotechnical problems require the determination of soil engineering properties such as shear strength. Therefore, the determination of the reliable values for this parameter is essential. For this purpose, the direct shear test, as one of the oldest tests to examine the shear strength of soils, is the most common way in laboratories to determine the shear parameters of soil. There are far too many variables that influence the results of a direct shear test. In this paper, a series of 10 × 10 cm direct shear tests were carried out on four different poorly graded sands with different particle size distributions to determine their shear behaviors. Four different poorly graded sands with a different median diameter or medium value of particle size distribution (D50) (0.2, 0.53, 1.3, and 2.3 mm) has been selected, and about 40 direct shear tests were conducted. It was concluded that a soil’s friction angle is affected by coarse-grained material. Accordingly, sandy soils with bigger particle sizes record a higher friction angle than soils containing small particles. The investigations also showed that sand with bigger particle sizes has a higher dilation angle. In addition, a non-linear regression analysis was performed to establish the exact relationship between the friction angle of the soil and the characteristics of the soil particles. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

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Study on Shear Strength Experiments Base on the Modified Direct Shear Apparatus for Unsaturated Soils

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.438-439.1176 ◽

2013 ◽

Vol 438-439 ◽

pp. 1176-1180 ◽

Cited By ~ 1

Author(s):

Gao Feng Chen ◽

Ying Fa Lv ◽

Zhi Huai Huang ◽

Yan Chang

Keyword(s):

Shear Strength ◽

Internal Friction ◽

Moisture Content ◽

Friction Angle ◽

Soil Samples ◽

Direct Shear ◽

Shear Strength Parameters ◽

Strength Parameters ◽

General Internal ◽

Direct Shear Apparatus

The unconsolidated-undrained fast shear tests of saturated-unsaturated remolded soil samples under different moisture content which is 1.1%, 10.1%, 14.9%, 19.9%, 24.2%, 29.9%, 37.7% respectively, and normal stress which is 50kPa, 100kPa, 200kPa, 300kPa, 400kPa respectively, were studied by the modified SDJ-1-type strain direct shear apparatus and U.S. Lab VIEW data acquisition system. The shear strength parameters of unsaturated soil samples, i.e. general cohesion and general internal friction angle were obtained based on Mohr-Coulomb strength theory. The test results showed that the general cohesion firstly increased and then reduced with the moisture content increasing, and the general internal friction angle increased with the moisture content decreasing. The function between the general shear strength parameters and the moisture content was studied. The concept of general shear strength parameters was proposed in the paper, and would provide a simple and practical method to obtain the strength parameters for engineering practice.

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Influence of Density on the Hydraulic and Mechanical Properties of Sands

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.580-583.659 ◽

2014 ◽

Vol 580-583 ◽

pp. 659-664

Author(s):

Osvaldo de Freitas Neto ◽

Olavo Francisco dos Santos Jr. ◽

Ricardo Nascimento Flores Severo

Keyword(s):

Shear Strength ◽

Hydraulic Conductivity ◽

Triaxial Compression ◽

Friction Angle ◽

Coarse Fraction ◽

Direct Shear ◽

Direct Shear Tests ◽

Strength Tests ◽

Constant Head ◽

Direct Shear Testing

This article aims at assessing the influence of relative density on the hydraulic conductivity and shear strength of two sands, denominated S01 and S02, derived from different regions and formation processes. S01 is wind-blown and S2 alluvial. The results of characterization and hydraulic conductivity in constant head tests were presented for both samples. The results of direct shear tests with sand S01 prepared with 5 different void ratios were also presented, for a vertical stress of 100kPa. The S02 sample was prepared with 4 different void ratios and these underwent direct shear testing with vertical stresses of 25kPa and 150kPa. This sample was prepared with the maximum and minimum void ratio and submitted to strength tests at CD triaxial compression with confining stresses of 50kPa, 100kPa and 200kPa. Results showed that even with different grain sizes, and under different density conditions, there were no significant variations in the permeability of the materials. With respect to shear strength, sand S01 obtained higher angle of friction values than sand S02, even though the latter had a higher percent coarse fraction. Sand S02 was relatively similar in terms of friction angle values obtained in direct shear and triaxial compression strength tests.

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