Effect Of Fiber Reinforcement Research Articles

Two-dimensional deformations in a rotating functionally graded fiber-reinforced thermoelastic half-space with magnetic field

The present study is concerned with the two-dimensional deformations in a rotating functionally graded (non-homogeneous), fiber-reinforced, transversely isotropic thermoelastic half-space under the effect of magnetic field in the context of Lord-Shulman theory. Material properties are supposed to be graded in -direction and normal mode technique is adopted to obtain the exact expressions for the temperature field, displacement and stress components. These results are computed numerically and depicted graphically to highlight the effects of fiber reinforcement, non-homogeneity parameter, magnetic field, rotation parameter and time on the variations of different physical fields. Certain particular cases of interest have been deduced from the current investigation.

Different Fiber Reinforcement Effects on Fly Ash-Based Geopolymer Long-Term Deflection in Three-Point Bending and Microstructure

This study investigated the effect of a low amount of polyvinyl alcohol (PVA) and steel fiber reinforcement on fly ash-based geopolymer composite long-term deflection and its microstructure. For testing purposes, specimens with different amounts and types of fiber reinforcement as well as plain (reference) were prepared. The long-term deflection test was performed by loading specimens with 40% of the ultimate flexural strength. A microstructure analysis was performed using polished section specimens, and images were acquired at 25-times magnification on a scanning electron microscope. The results of the flexural strength test show that all geopolymer composites with fiber reinforcement have lower flexural strength than plain geopolymer composites. The long-term deflection tests show that the highest deflections exhibit 1% PVA fiber-reinforced specimens. The lowest amount of deflection is for 1% steel fiber-reinforced specimens. Specific creep shows similar results to plain, and 1% steel fiber-reinforced specimens, while 1% PVA and 0.5% PVA/0.5% steel fiber-reinforced specimen exhibits the same properties. The quantitative microanalysis of the polished section further confirms the deflection results. Specimens with 1% PVA fiber reinforcement have significantly higher porosity than all other specimens. They are followed by plain specimens and 1% steel fiber, and 0.5% PVA/0.5 steel fiber-reinforced specimens have almost the same porosity level.

The effect of various fibers on the red mud additive sustainable geopolymer composites

In this paper, an experimental research was conducted to investigate some mechanical and microstructural properties of geopolymers composites based on red mud-metakaolin reinforced with four different fiber types and filled with brick dust-recycle aggregate filling material. Polypropylene, glass, polyvinyl alcohol and basalt fibers were used. The effect of fiber reinforcements on the strength properties and abrasion resistance of geopolymer composites was investigated, and microstructural analysis was performed to reveal the geopolymeric matrix composition, structure and bonding of the fibers. The results revealed that fiber reinforcement to metakaolin red mud-based geopolymers with brick waste powder and recycling aggregate improved the strength properties. For example, the presence of glass and polyvinyl alcohol fibers increased the flexural strength of geopolymer composites by 39% and 61%, respectively, compared to the control sample. Microstructural analysis revealed that the fibers gave an acceptable interfacial bond with the geopolymeric binder. The findings of the current article show a potential solution to becoming a sustainable geopolymer by presenting the successful use of red mud, recycling aggregate, and brick dust waste with different fibers as important asset materials.

Reinforcement Effect of Different Fibers on Asphalt Mastic.

Fiber materials as an asphalt mixture additive and stabilizer can effectively improve the performance index of asphalt pavement. In this study, lignin and carbon fiber were used as modifiers to study their effects on the road performance of asphalt mastic. Based on the frequency sweep, linear amplitude sweep (LAS) and multi-stress creep recovery (MSCR) experiments were conducted to test the high-temperature rutting and medium-temperature fatigue resistance of asphalt mastic with different fiber incorporation and low-temperature performance tests based on bending beam rheometer (BBR). The results indicate that adding fibers increased the stiffness of the asphalt mastic, and the modification effect of lignin fibers was better than that of carbon fibers. Meanwhile, the characteristic flow index of the asphalt mastic gradually increased with the increase in temperature, indicating that it gradually became a near-Newtonian fluid at higher temperatures. The addition of fibers also improved the high temperature rutting resistance of the asphalt mastic but did not have an advantageous effect on fatigue and low temperature cracking resistance. Additionally, the fitting results of the four-parameter Burgers model show that the use of fiber modification decreases the proportion of elasticity and viscous creep compliance but increases the delayed elasticity part.

Stabilization and Reinforcement Effect of Fibers on a Bitumen Binder.

This study investigated fibers' stabilization and reinforcement effect on a bitumen binder. The fibers' microstructures were primarily observed using scanning electron microscopy, and laboratory tests, including the oven heating and mesh-basket draindown, were designed and carried out on three different fiber-bitumen binders (lignin, mineral, and carbon fiber) in this paper to evaluate the bitumen adsorption and thermal stability, respectively. Then, the cone sink experiment was performed to check the rheological properties of these fiber-bitumen binders. These results reveal that the stabilization and reinforcement effect increases with the fiber content increasing to the optimal value. The optimal fiber content depends on the performance of the fiber-bitumen binder, and the value found in this paper is 0.4 wt %. The results indicate that the fiber enhances the toughness of the bitumen effectively via its spatial framework, adhesion, and stabilization of the fiber-bitumen binder. The rheological properties and rutting resistance were tested by a dynamic shear rheometer, and the results suggested that the fiber could effectively enhance the flow resistance and the rutting resistance of the fiber-bitumen binder.

Durable PP/EPDM/GF/SiO2 nanocomposites with improved strength and toughness for orthotic applications

Ankle-foot orthotics need ideal specification of being light-weight, high strength, tough, stiff, and durable. Reinforced polypropylene (PP) composites with enhanced mechanical properties are the most favorable materials being used in this field, but still, it is challenging to achieve balanced blend of strength and toughness in the composites. The present study thus aims to achieve the challenging task of simultaneous improvement in stiffness and toughness in reinforced PP composites exploring the synergistic reinforcement effect of glass fibers (GFs) and nano silica (SiO2) as multiscale fillers and ethylene propylene diene monomer (EPDM) as impact modifier. EPDM is used as toughness modifier, addressing the brittle behavior, but at the cost of the strength of the polymer. Combined use of micro and nanofillers as reinforcement in toughened polypropylene provides a potential approach to balance the strength while maintaining the toughness. GFs could offer high strength and nanofillers offer ductile fracture to the material. PP, PP/GF, PP/EPDM/GF composites and PP/EPDM/GF/SiO2 nanocomposites are fabricated through melt blending technique and are characterized through SEM, mechanical evaluation, nanoindentation and dynamic mechanical analysis. Mechanical properties are evaluated in accordance with ASTM standards. PP/EPDM/GF/SiO2 nanocomposites exhibits remarkable enhancement in Tensile strength, tensile modulus, impact strength and percent elongation at break by 49 MPa (55% increase over PP), 2450 MPa (145% increase), 145 J/m (13% increase) and 156% (160% increase) respectively. The exceptional improvement in reduced modulus and hardness reveals good interfacial properties. Loss factor decrement reveals elastic behavior of nanocomposites suitable for thermoforming of nanocomposites for orthotic device fabrication.

Fabrication of silver ions aramid fibers and polyethylene composites with excellent antibacterial and mechanical properties

Abstract Nowadays, with the continuous understanding of the pathogenic mechanism of bacterium, the demand for antibacterial plastic products had significantly increased. Besides that, many counties issued mandatory standards for plastic products, which imposed strict requirements on ash content to prevent the addition of excessive inorganic matter to plastics in order to avoid weakening the properties of plastics and deteriorating the recyclable property. Based on this, the development of composites with organic fiber-loaded antibacterial agents is of practicable value and urgency. We used an open-ring addition reaction to modified aramid fiber (AF) by utilizing epoxypropyltrimethoxysilane to react with the reactive groups on the surface of AFs. Subsequently, the modified fibers were surface loaded with silver ionic glass beads. After that, a series of high-density polyethylene composites with excellent mechanical properties and antibacterial properties were prepared using melt mixing method. It was shown that the composite had a low ash value (1.88 wt%) even at a higher filling concentration (7 wt%) and the fibers could change the crystalline properties and morphology of the composite. Because of the fiber reinforcement and crystallization induction effects, the tensile strength and elasticity module of the composites could be improved by 141% and 136%, respectively. In addition, the composites had excellent long-lasting contact antibacterial effects against the inhibition of E. coli. The proposed organic fiber loading technique and antibacterial composites will provide a method for designing and preparing eco-friendly and high-performance plastic products.

Effect of fiber reinforcement on self-healing ability of asphalt mixture induced by microwave heating

Microwave heating is considered to be an effective method for accelerating the healing of the asphalt mixture with cracks that contain microwave-absorbing materials. Three fibers as microwave-absorbing materials (i.e., carbon fiber, steel fiber and steel wool) were used to fabricate self-healing asphalt mixtures, and their mechanical properties and self-healing ability were evaluated by semi-circular bending test. Effect of freeze–thaw cycles on the mechanical properties and healing effect of fiber modified asphalt mixtures were investigated, and the different fiber reinforcing effects were studied by the digital image correlation. Results show that although the addition of fibers can greatly improve the mechanical properties and healing ability of mixtures, freeze–thaw cycles have great adverse effects on these performances. Among the three fibers, steel fiber has the strongest reinforcement effect on the fracture behavior of asphalt mixture, and its reinforcement effect and healing ability are also less affected by moisture and freeze–thaw effect than that of steel wool and carbon fiber. Carbon fiber modified asphalt mixture has the lowest fracture and freeze–thaw resistance. Considering the harmful impacts of freeze–thaw cycles and the beneficial impacts of fiber reinforcing effect, steel fiber is recommended for fabricating self-healing asphalt mixture.

Effects of Glass Wool Residue Recycled Admixtures on the Properties of Portland Cement-Based Composites

In this study, the effects of a recycled mineral admixture based on glass wool residue (GWR) in microstructural and mechanical properties of ordinary portland cement (OPC)-based composites are examined. The GWR was dried and milled into a fine powder, whereby it was physicochemically characterized. Physicomechanical tests, quantitative X-ray diffraction, and scanning electron microscope observation were performed in pastes and mortars at 28, 56, and 90 days of age. Moreover, the potential application of the GWR was evaluated by determining the pozzolanic activity and the fiber reinforcement effect. The results showed that the partial replacement of cement by 25% by weight of GWR presented no reductions in flexural strength at 28 and 56 days of curing, whereas the long-term flexural strength increased by 17%. This replacement also increased the long-term compressive strength of the composites—reaching a strength activity index of 1.06. The results also showed that GWR presented some fiber reinforcement effect—depending on the particle size. Promising properties were observed for samples blended with GWR, yielding technical, environmental, and economic benefits.

Performance Evaluation of Lime, Cement and Alkali-Activated Binder in Fiber-Reinforced Expansive Subgrade Soil: A Comparative Study

Abstract Expansive subgrade soils show early distresses causing distortion and premature failure to pavement structures. In the present study, an attempt is made to enhance the subgrade strength characteristics of the expansive soil by treatment with an alkali-activated binder (AAB) and reinforcement with four types of fibers (polypropylene [PF], glass, hemp, and coir fiber [CF]). The research also compares the effectiveness of fiber reinforcement in geopolymerized alkaline soil with the traditional lime and cement binders. AAB is produced by the reaction in an alkaline activator of sodium silicate and sodium hydroxide with aluminosilicate precursors (Class-F fly ash and slag) by maintaining a 0.4 water-to-solid ratio. The effect of varying dosages of fibers and slag/fly ash ratio in the alkaline, lime, and cemented soil mixture on unconfined compressive strength (UCS), split tensile strength (STS), and flexural and penetration resistance is evaluated through a series of geomechanical and microstructural characterization tests. California bearing ratio (CBR) and flexural strength (Sf) are chosen as a subgrade strength performance indicator for fiber-reinforced soil. It is observed that PF-AAB soil shows higher interfacial bonding with strong interlocking density and tensile cracking resistance. The combined inclusion of fiber reinforcement (> 0.5 %) with 0.66 slags/fly ash ratio (S40 F60) in the alkaline mixture increased the subgrade strength performance indicator (flexural and elasticity) by around 35 %–40 % over the lime-cement soil-fiber mixture. The corresponding CBR, UCS, and STS values were also found to have increased by 55 %–65 %. Furthermore, the uncertainties associated with subgrade strength failure are predicted in the form of the CBR reliability index using Monte Carlo simulation through a nonlinear regression model developed from experimental results. The study shows that the optimum dosages of fiber reinforcement and slag/fly ash are essential factors for regulating the volumetric instability and tensile cracks of expansive soil.

Effect of excessive fiber reinforcement on mechanical properties of chopped glass fiber reinforced polymer concretes

Polymer concretes (PCs) have evolved with the growing need for special concretes in the construction sector such as swimming pools, sewer structures, drainage channels, reinforcement injection, and other structures that contain liquids or corrosive chemicals. Recently, these concretes have been prioritized and their importance is growing. In this study, chopped glass fiber (CGF) reinforced polymer concretes (CGFRPCs) are emphasized and the effect of excessive fiber reinforcement on the mechanical properties of concrete is investigated. In this regard, six different mixtures; M1 (Pure PC), M2 (0.15 % CGFs), M3 (0.20 % CGFs), M4 (0.25 % CGFs), M5 (0.50 % CGFs), M6 (1.0 % CGFs); were prepared by considering 0, 0.6, 0.8, 1, 2 and 4 reinforcing indexes (RIs) with a constant aspect ratio (6/0.015 = 400), respectively. Then, the initial setting time, final setting time, peak temperature and flow tests are performed on the fresh concrete samples. The density, flexural strength and compressive strength at 7, 14, 21 and 28 days are determined on the prism and cube samples as the hardened concrete tests. Besides, scanning electron microscope (SEM) examinations are performed to obtain detailed information about the behavior of the concretes. The experimental studies and SEM evaluations show that excessive fiber reinforcement negatively affects both fresh concrete properties and hardened concrete properties because of fiber agglomeration, thixotropy, fiber pull-out, fiber breakage, dislodged aggregate, interface and matrix cracks. In addition, it is observed that the problems observed in the CFRPCs increase as the RI increases.

Effect of Fiber Reinforcement on Creep and Recovery Behavior of Cement-Emulsified Asphalt Binder.

In order to evaluate and improve the deformation behavior of cement-emulsified asphalt binder (CA) in cement-emulsified asphalt mixture, this study investigated the reinforcement of small additions of fibers (2%, 4%, and 6% addition by mass of cement) on the deformation resistance of CA. A repeated creep recovery test was implemented that measures the recovery rate of creep deformation and accumulated strain. Further, an improved piecewise curve-fitting method was used to determine the parameters of Burgers model, then the creep compliances were fitted and calculated. The results show the repeated creep recovery test to be a suitable method for obtaining useful information about creep and recovery deformation of fiber-reinforced CA. The influence of fiber types and dosages on the deformation recovery ability is determined based on the creep recovery ratio and accumulated strain. The improved piecewise curve-fitting method has high accuracy. Thereafter, the reinforcement effect was analyzed through the evolution of creep compliance under loading. Therefore, this paper can provide a reference for enhancing the properties of cement-emulsified asphalt mixture by maximizing the fiber reinforcement.

Experimental Investigation of Cracking and Impact Resistance of Polymer- and Fiber-Enhanced Concrete for Ultra-Thin Whitetopping.

In order to investigate the effectiveness of polymer modification and fiber reinforcement on the cracking and impact resistance of concrete materials prepared for ultra-thin whitetopping (UTW), carboxyl butyl benzene latex and polyformaldehyde fibers were added to the conventional cement concrete mix. In addition, test methods that used an asphalt mixture performance tester (AMPT) and mechanical rammer were developed to evaluate concrete cracking and impact resistance, respectively. Results from the AMPT test revealed that the cracking resistance can be enhanced with polymer and fiber, especially the initial tensile load peak, which can be improved by more than 40% when fiber and polymer compound modification is applied. Meanwhile, the impact loading test revealed that the inclusion of both fiber and polymer results in a two-fold increase in the number of impacts before visible cracking occurs, and the number of blows to failure increased by 21.4%. Moreover, microstructures were investigated by scanning electron microscopy (SEM) to confirm the reinforcing mechanism of both polymer modification and fiber reinforcement.

Assessment of the Natural Fiber Reinforced Bio-Polyethylene Composites Flexural Macro and Micromechanical Properties

ABSTRACT One of the most common load modes is flexure. The paper measures and models the flexural strength and modulus of a bio-polyethylene reinforced with thermos-mechanical fibers from corn stover. Moreover, the authors use modified rules of mixtures to evaluate the contribution of the reinforcements to the properties of the composite. It was found a high impact of coupling agent content on the strength of the composites, and materials with a 6% of such agent and 50% of reinforcement increased 181% the strength of the matrix, and 464% its modulus. The obtained values are noticeable higher than polypropylene and some of its composites. Micromechanics analysis shows that the effect of natural fiber reinforcement on the flexural properties of a bio-based PE is similar to the effects on a polyolefin. Thus, the use of fully bio-based composites can be proposed as a substitute for some oil-based polymers, partially bio-based materials, and their composites.

Effect of Natural Fibers Reinforcement of Honeycomb Sandwich Using Numerical Analysis

The honeycomb sandwich structure has been extensively investigated for its mechanical performance. Modification in improving such mechanical properties is an innovation required for honeycomb sandwiches, especially by adding a random fibers reinfo

The effects of toolpath and glass fiber reinforcement on bond strength and dimensional accuracy in material extrusion of a hot melt adhesive

In this work, a polyamide hot melt adhesive (Technomelt PA 6910) and its glass fiber-filled composite (Loctite 3D 6910) were evaluated as feedstocks for desktop-scale thermally-driven material extrusion additive manufacturing (AM). Technomelt PA 6910 is a semicrystalline polymer with a sub-ambient glass transition temperature, intermediate melting temperature, and low recrystallization temperature. This paper aims to study the effect of glass fibers and toolpath on mechanical properties, warpage, and dimensional accuracy of prints. Glass fibers improved the yield strength of 0° raster angle bars, but reduced the strength of 90° raster angle samples. The reduced weld strength was more significant in samples cut from single road width boxes than multilayer (≈3.2 mm thick) specimens due to fast cooling of thin parts. Glass fibers prevented warpage and excessive spread of initial layers of boxes. Toolpath affected tensile properties for Technomelt PA 6910, in which longer toolpaths resulted in higher warpage and decreased tensile strength of parts due to longer layer times, but did not affect tensile properties for Loctite 3D 6910. While Technomelt PA 6910 exhibits isotropic tensile properties, the addition of glass fibers resulted in anisotropic properties of Loctite 3D 6910 bars, which was more significant in single road (≈0.4 mm thick) parts. Multilayer Loctite 3D 6910 structures are stronger, which makes this material more appropriate for larger scale applications in which there is a high thermal mass and slumping is a significant printing challenge.

Effect of Multi-Walled Carbon Nanotubes and Carbon Fiber Reinforcements on the Mechanical and Tribological Behavior of Hybrid Mg-AZ91D Nanocomposites.

Magnesium matrix composites are extensively used in automotive and structural applications due to their low density, high strength, and wear-resistant properties. To reach the scope of industry needs, research is carried out regarding enhancing the mechanical and tribological behavior of the magnesium composites by reinforcing the nano-sized reinforcements. In the present work, research has been carried out to enhance the properties of the magnesium AZ91D hybrid composite by reinforcing carbon fibers (CFs) and multi-walled carbon nanotubes (MWCNTs) with varying weight percentages (AZ91D + 0.5% CF’s + 0.5% MWCNT and AZ91D + 0.75% CF’s + 0.75% MWCNT, respectively). The experimental tests were carried out to evaluate the mechanical and tribological behavior of the composites. The test results showed that the addition of CF and MWCNT reinforcements improved the hybrid Mg composite’s hardness, tensile strength, and impact strength compared to the base Mg matrix. The AZ91D + 0.75% CF’s + 0.75% MWCNT hybrid composite showed a 19%, 35%, and 66% increased hardness, tensile strength, and impact strength, respectively, compared to the base Mg AZ91D. The wear test results also showed the improved wear resistance of the Mg composite compared to the base matrix. The enhanced wear resistance of the composite is due to the addition of hard MWCNT and CF reinforcements. The wear rate of the AZ91D + 0.75%CF’s + 0.75% MWCNT composite for a load of 30 N at a sliding distance of 1500 m is lower as compared to the base matrix. The SEM micrographs of the worn surfaces revealed the existence of abrasive wear. The improved mechanical and tribological behavior of the magnesium composite is also due to the homogeneous distribution of the hard reinforcement particles along the grain boundaries.

Research methodology to pineapple fiber reinforcement effect in polylactic material

Researching new materials that are environment friendly has become a global purpose. Given the current contamination situation, mainly due to plastic, the using pineapple waste option as a bio composite production source is presented. The methodology used in this project is presented to achieve the material’s development, the problems presented and the results obtained in the work progress.

Evaluation of Surface Topography of Heat Cure Acrylic Denture-base Resin before and after Reinforcement with Different Fibers Using Stylus-based Profilometer

The aim of this in vitro study was to evaluate the effect of glass and nylon fiber reinforcement on surface topography of polymethyl methacrylate (PMMA) denture resin after polishing. Stainless steel dies were used for preparation of specimens and were divided into three groups of 30 specimens each. Group A: Control group, Group B: PMMA reinforced with glass fibers, Group C: PMMA reinforced with nylon fibers. All specimens were finished and polished by a single operator to eliminate any inadvertent bias and ensure a constant pressure when polishing. The surface roughness of all the acrylic samples was measured with the help of profilometer (SURFCOM 130A). Glass-reinforced PMMA showed higher mean surface roughness (0.16817 µm) as compared to unreinforced PMMA (0.10203 µm). Nylon-reinforced PMMA showed lower mean surface roughness (Ra) of 0.09177 µm as compared to unreinforced PMMM (0.10203 µm). Glass-reinforced PMMA showed a higher mean surface roughness (Ra) of 0.16817 µm as compared to nylon PMMA (0.09177 µm). Reinforcement with glass and nylon fibers affects the surface roughness of the PMMA resin, i.e., glass fibers increase the surface roughness of PMMA resin, whereas nylon fibers slightly decrease the surface roughness of PMMA resin. Hence, the use of nylon fiber may be justified to obtain a denture with increased fracture resistance, acceptable esthetic properties, and better denture hygiene and plaque accumulation. Two important parameters are essential for ensuring the durability of a restorative material, which include surface roughness and color stability. Surface roughness may be the major cause of discomfort for the patient and it may be associated with complications by promoting the deposition of biofilm and microbial growth. The use of nylon fiber increases fracture resistance and provides acceptable esthetic properties and better denture hygiene and plaque accumulation.

Yüksek Sıcaklığın Polipropilen Lif Takviyeli Horasan Harcının Bazı Özelliklerine Etkisi

In many parts of the world, it is known that lime-based mortars and plasters are used in buildings that have the characteristics of historical monuments. On the other hand, Khorasan mortar is a traditional type of lime-based mortar that is frequently found in historical buildings that constitute the important cultural heritage of our country. Khorasan mortar was used as a masonry mortar and plaster during the construction of structures for centuries. It is also frequently preferred in the restoration works of these structures. For this reason, studies are continuing to improve the strength and durability properties of this mortar. In this study, the effect of polypropylene fiber reinforcement on some properties of Khorasan mortar specimens exposed to high temperatures was investigated. For this purpose, in addition to the control mixture, four different mortar mixtures containing 3 mm long polypropylene fiber at 0.4, 0.6 and 0.8% ratios were prepared. Water/binder, aggregate/binder ratios and target flow value for all mixtures were constant at 0.91, 3.0 and 150±10 mm, respectively. 80% of the binder mass consists of natural hydraulic lime and 20% of brick dust in all mixtures. 70% crushed brick and 30% river sand were used as aggregate. At the end of the 90-day curing period, the unit weight, ultrasonic pulse velocity and modulus of dynamic elasticity values of the mortar specimens were determined in their initial state and after exposure to 300, 600, 900 ˚C. As a result of the experimental study, it was determined that the need for water-reducing admixture increased to reach the target flow value with the increase in fiber utilization ratio in mortar mixtures. In addition, depending on the fiber utilization ratio, it was observed that the values in question decreased in the initial state and after exposure to a temperature of 300 ˚C. At higher temperatures, fibrous and non-fibrous specimens were found to have similar properties in terms of ultrasonic pulse velocity and modulus of dynamic elasticity.