scholarly journals Behavior of Fiber-Reinforced and Lime-Stabilized Clayey Soil in Triaxial Tests

2019 ◽  
Vol 9 (5) ◽  
pp. 900 ◽  
Author(s):  
Yixian Wang ◽  
Panpan Guo ◽  
Xian Li ◽  
Hang Lin ◽  
Yan Liu ◽  
...  
Keyword(s):  
Wheat Straw ◽  
Clayey Soil ◽  
Coupling Effect ◽  
Fiber Reinforcement ◽  
Reinforced Soil ◽  
Triaxial Tests ◽  
Fiber Reinforced ◽  
Microscopic Mechanism ◽  
Lime Stabilization ◽  
Stabilized Soil

The beneficial role of combining fiber reinforcement with lime stabilization in altering soil behavior has been established in the literature. However, the coupling effect of their combination still remains unclear in terms of its magnitude and microscopic mechanism, especially for natural fibers with special microstructures. The objective of this study was to investigate the coupling effect of wheat straw fiber reinforcement and lime stabilization on the mechanical behavior of Hefei clayey soil. To achieve this, an experimental program including unconsolidated–undrained (UU) triaxial tests and SEM analysis was implemented. Static compaction test samples were prepared on untreated soil, fiber-reinforced soil, lime-stabilized soil, and lime-stabilized/fiber-reinforced soil at optimum moisture content with determining of the maximum dry density of the untreated soil. The lime was added in three different contents of 2%, 4%, and 6%, and 13 mm long wheat straw fiber slices with a cross section one-quarter that of the intact ones were mixed in at 0.2%, 0.4%, and 0.6% by dry weight of soil. Analysis of the derived results indicated that the addition of a small amount of wheat straw fibers into lime-stabilized soil improved the intensity of the strain-softening behavior associated with mere lime stabilization. The observed evidence that the shear strength increase brought by a combination of 0.4% fiber reinforcement and 4% lime stabilization was smaller than the summation of the shear strength increases brought by their presence alone in a sample demonstrated a coupling effect between fiber reinforcement and lime stabilization. This coupling effect was also detected in the comparisons of the secant modulus and failure pattern between the combined treatment and the individual treatments. These manifestations of the coupling effect were explained by a microscopic mechanism wherein the fiber reinforcing effect was made more effective by the ways in which lime chemically stabilized the soil and lime stabilization development was quickened by the water channels passing through the surfaces and honeycomb pores of the wheat straw fibers.

scholarly journals Behavior of granular rubber waste tire reinforced soil for application in geosynthetic reinforced soil wall

2015 ◽  
Vol 8 (4) ◽  
pp. 567-576 ◽  
Author(s):  
G. G. D. RAMIREZ ◽  
M. D. T. CASAGRANDE ◽  
D. FOLLE ◽  
A. PEREIRA ◽  
V. A. PAULON
Keyword(s):  
Clayey Soil ◽  
Reinforced Soil ◽  
Unit Weight ◽  
Triaxial Tests ◽  
Rubber Mixture ◽  
Waste Tire ◽  
Backfill Material ◽  
Geosynthetic Reinforced Soil ◽  
Rubber Waste ◽  
Reinforced Soil Wall

AbstractLarge quantities of waste tires are released to the environment in an undesirable way. The potential use of this waste material in geotechnical applications can contribute to reducing the tire disposal problem and to improve strength and deformation characteristics of soils. This paper presents a laboratory study on the effect of granular rubber waste tire on the physical properties of a clayey soil. Compaction tests using standard effort and consolidated-drained triaxial tests were run on soil and mixtures. The results conveyed an improvement in the cohesion and the angle of internal friction the clayey soil-granular rubber mixture, depending on the level of confining stress. These mixtures can be used like backfill material in soil retaining walls replacing the clayey soil due to its better strength and shear behavior and low unit weight. A numerical simulation was conducted for geosynthetic reinforced soil wall using the clayey soil and mixture like backfill material to analyzing the influence in this structure.

Experimental Study of Granular Rubber Waste Tire Reinforced Soil for Geotechnical Applications

2014 ◽  
Vol 600 ◽  
pp. 585-596 ◽  
Author(s):  
Gary G.D. Ramirez ◽  
Michéle D.T. Casagrande
Keyword(s):  
Clayey Soil ◽  
Dry Weight ◽  
Reinforced Soil ◽  
Triaxial Tests ◽  
Confining Stress ◽  
Rubber Mixture ◽  
Angle Of Internal Friction ◽  
Waste Tire ◽  
Rubber Waste ◽  
Geotechnical Characteristics

Large quantities of waste tires are released to the environment in an undesirable way. The amount of this scrap is increasing every year. The potential use of this waste material in geotechnical applications can contribute to reducing the tire disposal problem and to improve strength and deformation characteristics of soils. This paper presents a laboratory study on the effect of granular rubber waste tire on the physical properties of a clayey soil. Clayey soil was mixed with 10% of granular rubber by dry weight. Grain size, Atterberg limits analyses and compaction tests using standard effort were performed on the clayey soil. Consolidated-drained triaxial tests at confining stresses of 50, 100, 200 and 400 kPa were run on soil and mixture. The results conveyed that the geotechnical characteristics are influenced by the addition of grained tire, improving the cohesion and the angle of internal friction the clayey soil-granular rubber mixture. This improvement depends on the level of confining stress. The compaction test results indicated that the dry unit weights and the optimum moisture for the mixture decreased in relation to clayey soil. Therefore, this mixture can be used as lightweight fill material due to its low specific weight, solving low bearing capacity and high settlement problems of embankments on soft compressible soils.

scholarly journals Direct Shear Creep Characteristics and Microstructure of Fiber-Reinforced Soil

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Hao Tang ◽  
Huahua Li ◽  
Zhao Duan ◽  
Chiyang Liu ◽  
Guannan Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fiber Reinforcement ◽  
Reinforced Soil ◽  
Fiber Content ◽  
Direct Shear ◽  
Fiber Reinforced ◽  
Creep Tests ◽  
Shear Creep ◽  
Before And After ◽  
Fiber Reinforced Soil

Fiber-reinforced soil is an excellent engineering material that has become a focus of research. Most studies focus on the conventional mechanical properties of reinforced soil, such as its tensile, compressive, and shear strength, and rarely study its creep-related mechanical properties. However, when such soil is used as backfill, the creep effect should not be ignored. This study explored the characteristics of creep mechanics in reinforced soil, the fiber-reinforcement mechanism, and the dynamics of microstructures before and after creep tests. Direct shear creep tests were carried out using a direct shear creep tester on soil reinforced with natural palm fibers of equal length (1.5 cm) in different amounts (0%, 0.2%, 0.6%, 1.0%). Microscale tests were carried out on the reinforced soil samples before and after the creep tests by polarized light and scanning electron microscopy. The results show that the fiber reinforcement can restrain the deformation and enhance the long-term strength of soil. However, a nonlinear relationship between the reinforcement effect and fiber content was found, with 0.6% being the optimal content. Palm fibers have rough surfaces, grooves, and independent pore chambers, which increase the effective contact area and interaction with the soil. With increases in fiber content, the fibers interweave to form a nestled network structure, which increases the strength and integrity of the soil. Fiber addition changes the microstructure of the soil pores; the proportion of large pores decreases and that of small pores increases. Under the effect of creep, the pore changes follow the principle of pore homogenization; large pores are destroyed and transformed into small pores, causing the porosity of reinforced soil to decrease faster and be less porous than unreinforced soil. This research can provide technical reference for the engineering application of palm fiber-reinforced soil.

Mechanical Behavior of Reinforced Clayey Soil with Fine Crushed Polyethylene Terephthalate

2015 ◽  
Vol 668 ◽  
pp. 404-410 ◽  
Author(s):  
Ingrid Milena Reyes Martínez ◽  
Nathalia dos Santos Lopes Louzada ◽  
Lucas Mendes Repsold ◽  
Michéle D.T. Casagrande
Keyword(s):  
Mechanical Behavior ◽  
Polyethylene Terephthalate ◽  
Clayey Soil ◽  
Dry Weight ◽  
Friction Angle ◽  
Reinforced Soil ◽  
Triaxial Tests ◽  
Strength Parameters ◽  
Pet Waste ◽  
Strength And Deformation

Currently a lot of bottles of polyethylene terephthalate (PET) are discarded into the environment. In order to reduce the disposal of this polymer in nature, this study aims to evaluate the mechanical behavior of a clayey soil mixed with fine crushed PET. The potential use of this waste material in geotechnical applications may ultimately reduce the problem of improper disposal and improve the strength and deformation characteristics of the soil. This paper presents an experimental study to evaluate the mechanical behavior of pure soil and mixtures with different contents of PET waste by triaxial tests, in order to obtain the strength parameters of the Soil-PET mixtures. The clayey soil used was mixed with 10 and 20 percent of fine crushed PET by dry weight. Characterization tests such as grain size, Atterberg limits and compaction test were performed on the soil-PET mixtures. Triaxial tests at confining stresses of 50, 150 and 300 kPa were done on the soil and mixtures. The results show that the soil strength parameters are influenced by the addition of the fine crushed PET, thus improving characteristics such as friction angle and cohesion of the Soil-PET mixtures. This improvement also depends on the confining level which the samples were submitted. These mixtures may be used in pavement and other geotechnical works, so this paper proposes to contribute to a better understanding and interpretation of the behavior of reinforced soil with waste PET.

scholarly journals Finite Element Analysis for Nonlinear Unbonded Circular Fiber-Reinforced Elastomeric Bearings

2021 ◽  
Vol 5 (7) ◽  
pp. 170
Author(s):  
Pablo Castillo Ruano ◽  
Alfred Strauss
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Carbon Fiber ◽  
Seismic Isolation ◽  
Nonlinear Viscoelasticity ◽  
Fiber Reinforcement ◽  
Special Focus ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Elastomeric Bearings

In recent years, interest in low-cost seismic isolation systems has increased. The replacement of the steel reinforcement in conventional elastomeric bearings for a carbon fiber reinforcement is a possible solution and has garnered increasing attention. To investigate the response of fiber-reinforced elastomeric bearings (FREBs) under seismic loads, it is fundamental to understand its mechanical behavior under combined vertical and horizontal loads. An experimental investigation of the components presents complexities due to the high loads and displacements tested. The use of a finite element analysis can save time and resources by avoiding partially expensive experimental campaigns and by extending the number of geometries and topologies to be analyzed. In this work, a numerical model for carbon fiber-reinforced bearings is implemented, calibrated, and validated and a set of virtual experiments is designed to investigate the behavior of the bearings under combined compressive and lateral loading. Special focus is paid to detailed modeling of the constituent materials. The elastomeric matrix is modeled using a phenomenological rheological model based on the hyperelastic formulation developed by Yeoh and nonlinear viscoelasticity. The model aims to account for the hysteretic nonlinear hyper-viscoelastic behavior using a rheological formulation that takes into consideration hyperelasticity and nonlinear viscoelasticity and is calibrated using a series of experiments, including uniaxial tension tests, planar tests, and relaxation tests. Special interest is paid to capturing the energy dissipated in the unbonded fiber-reinforced elastomeric bearing in an accurate manner. The agreement between the numerical results and the experimental data is assessed, and the influence of parameters such as shape factor, aspect ratio, vertical pressure, and fiber reinforcement orientation on stress distribution in the bearings as well as in the mechanical properties is discussed.

Shear strength of reinforced concrete beams with a fiber concrete matrix

2006 ◽  
Vol 33 (6) ◽  
pp. 726-734 ◽  
Author(s):  
Fariborz Majdzadeh ◽  
Sayed Mohamad Soleimani ◽  
Nemkumar Banthia
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Reinforcement ◽  
Shear Capacity ◽  
Fiber Reinforced Concrete ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Fiber Volume

The purpose of this study was to investigate the influence of fiber reinforcement on the shear capacity of reinforced concrete (RC) beams. Both steel and synthetic fibers at variable volume fractions were investigated. Two series of tests were performed: structural tests, where RC beams were tested to failure under an applied four-point load; and materials tests, where companion fiber-reinforced concrete (FRC) prisms were tested under direct shear to obtain material properties such as shear strength and shear toughness. FRC test results indicated an almost linear increase in the shear strength of concrete with an increase in the fiber volume fraction. Fiber reinforcement enhanced the shear load capacity and shear deformation capacity of RC beams, but 1% fiber volume fraction was seen as optimal; no benefits were noted when the fiber volume fraction was increased beyond 1%. Finally, an equation is proposed to predict the shear capacity of RC beams.Key words: shear strength, fiber-reinforced concrete, RC beam, stirrups, energy absorption capacity, steel fiber, synthetic fiber.

scholarly journals ANALYSIS OF PROPERTIES OF CONCRETE USING STEEL FIBERS AS FIBER REINFORCEMENT ADMIXTURE

2017 ◽  
Vol 5 (4RASM) ◽  
pp. 59-62
Author(s):  
Vishal Gadgihalli ◽  
Meena ◽  
Sindu ◽  
Raghavendra Prasad Dinakar
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Steel Fibre ◽  
Fiber Reinforcement ◽  
Paper Analysis ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Different Types ◽  
Discrete Uniform

Fiber reinforced concrete is composite material consisting of mixtures of cement, mortar or concrete, discontinuous discrete uniform dispersed suitable fibers. Fiber reinforced concrete are of different types and properties. In this paper analysis of properties of concrete using steel fibre as fiber reinforcement admixture is studied and verified the strength of concrete to normal plane concrete with absence of admixtures. Using steel fibers as fiber reinforcement admixture increases bond strength by enhancing surface tension as steel is better in taking flexural strength this gives better results, hence we can use this steel fiber reinforcement to concrete where the compressive and flexural strength place a crucial role in construction and maintenance.

scholarly journals PENGARUH KOMPOSISI BEBERAPA GLASS FIBER NON DENTAL TERHADAP KEKUATAN FLEKSURAL FIBER REINFORCED COMPOSITES

2018 ◽  
Vol 2 (1) ◽  
pp. 29-35
Author(s):  
Widya Puspita Sari ◽  
Siti Sunarintyas ◽  
Nuryono Nuryono
Keyword(s):  
Glass Fiber ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Fiber Reinforcement ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Flowable Composite ◽  
Silane Coupling

E-glass fiber merupakan fiber reinforcement yang sering digunakan di kedokteran gigi karena berikatan baik dengan polimer melalui silane coupling agent, meningkatkan kekuatan mekanis dan tidak sensitif terhadap kelembaban. Ketersediaan E-glass fiber dental di Indonesia terbatas dengan harga relatif mahal. Glass fiber non dental banyak tersedia di Indonesia dengan harga terjangkau, yang biasa digunakan pada pembuatan panel gypsum dan komponen otomotif. Tujuan penelitian ini adalah mengetahui pengaruh komposisi glass fiber non dental terhadap kekuatan fleksural fiber reinforced composites. Bahan yang digunakan dalam penelitian ini adalah E-glass fiber dental (Fiber-splint, Polydentia SA, Switzerland), glass fiber non dental A (LT, China), B (CMAX, China) dan C (HJ, China), flowable composite (CharmFil Flow, Denkist, Korea) dan silane coupling agent (Monobond S, Ivoclar Vivadent, Liechtenstein). Subjek dibagi dalam 5 kelompok: tanpa fiber, E-glass fiber dental, glass fiber non dental A, B dan C . Uji kekuatan fleksural berdasarkan ISO 10477. Hasil yang diperoleh dianalisis menggunakan ANAVA satu jalur. Hasil penelitian menunjukkan rerata kekuatan fleksural (MPa) terendah pada kelompok tanpa fiber (126,18±5,21) dan tertinggi pada kelompok glass fiber non dental A (208,03±8,32). Hasil ANAVA satu jalur menunjukkan pengaruh bermakna dari komposisi fiber terhadap kekuatan fleksural (α < 0,05). Kesimpulan penelitian: Kandungan SiO2, Al2O3 dan alkali tanah oksida (MgO dan CaO) yang tinggi pada glass fiber meningkatkan kekuatan fleksural dari fiber reinforced composites.

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