Influence Of Fiber Type Research Articles

Strength development and microstructure characteristics of artificial concrete pillar considering fiber type and content effects

The artificial concrete pillar (ACP) replacement technique is a safe and reliable method to safely mine orebody pillar in room and pillar mining. In contrast to traditional ore pillar, artificial pillar has recently received significant attention due to its applicability, stability and cost benefits. This study deals the influence of fiber type and content on uniaxial compressive strength (UCS) and microstructure characteristics of fiber-reinforced concrete (FRC) considered as an effective artificial pillar. A total of 3 non-FRC (NFRC) and 27 FRC samples reinforced with glass, polypropylene (PP), and polyacrylonitrile (PAN) fibers at a content of 0 wt%, 0.4 wt%, 0.8 wt% and 1.2 wt% were manufactured for examining their strength properties. After UCS testing, some microstructure tests including computed tomography scan and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy were done to better explore the morphology of FRC. Results illustrate that: (1) The UCS values of all FRC samples first increase and then decrease with increasing fiber content. The UCS increment ratio in FRC steadily decreases as the fiber content increases. (2) PP fiber was more effective than both glass and PAN fibers in increasing peak strain and strength performance. This was mainly because of an improved bonding quality within the matrix which allows to decrease the water absorption of FRC. Overall, the peak strain increases linearly with increasing fiber content. Finally, the findings of this study can offer a substantial reference in design and application of FRC to be used as artificial pillar in underground mines.

Fabrication and characterization of femtosecond laser induced microwave frequency photonic fiber grating.

We proposed and fabricated a microwave-frequency photonic fiber grating (MPFG) by femtosecond laser micromachining on optical fibers. Illuminated by low coherent light source, the MPFG can be interrogated using proposed microwave photonic system to show the resonant peaks in microwave frequency domain. We studied the working principle and characteristics of this device. After that, we discussed the influence of fiber type, apodization and light source coherence lengths on this device. The device can also respond to ambient temperature change like fiber optic sensors.

Durability of the Reinforced One-Part Alkali-Activated Slag Mortars with Different Fibers

This paper investigates the effects of reinforcing one-part alkali-activated slag binders (OAASs) with different types of fiber (steel, polyvinyl alcohol [PVA], basalt, and cellulose) and fiber combinations (single and hybrid) on the mechanical and durability properties of OAASs. All OAASs were reinforced by a 1% fiber volume fraction. Compressive and flexural strengths were the mechanical properties, which were addressed. The durability of the reinforced OAASs was examined based on water absorption by immersion and capillary, acid resistance, high temperature resistance, carbonation resistance, and freeze/thaw resistance. The experimental results showed that the fiber type and combination greatly affects the mechanical and durability properties of OAASs. Moreover, the influence of fiber type and combination on high temperature resistance and freeze/thaw resistance is greater than the influence on acid resistance and carbonation resistance.Graphic

Effect of fiber characteristics on fresh properties of fiber-reinforced concrete with adapted rheology

The influence of fiber type and volume on fresh properties of fiber-reinforced self-consolidating concrete (FR-SCC) and fiber-reinforced super-workable concrete (FR-SWC) was investigated. These mixtures were developed for infrastructure construction and repair, respectively, and the fibers were incorporated to reduce cracking and enhance service life of concrete structures. The fibrous mixtures were proportioned with a Type-G expansive agent (EA) to reduce shrinkage and mitigate the risk of cracking. The selected fibers included a propylene synthetic fiber, five different steel fibers, and a hybrid fiber containing steel and polypropylene multifilament fibers. The fiber volume was fixed at 0.5% for the FR-SCC mixtures and varied between 0.5% and 0.75% for the FR-SWC. The investigated FR-SCC and FR-SWC mixtures had initial slump flow of 660–700 mm and 505–570 mm, respectively, and exhibited excellent passing ability and adequate stability. The investigated FR-SCC and FR-SWC mixtures with passing ability index greater than or equal to 12 and 11, respectively, evaluated using the modified J-Ring test exhibited good flowability without blockage and segregation. The passing ability index was inversely proportional to plastic viscosity for mixtures of a given coarse aggregate content and maximum nominal size of aggregate. Good relationships between slump flow and yield stress and T50 and plastic viscosity were established for the fibrous mixtures.

Drilling of In-Line Compression Molded Jute / Polypropylene Composites

ABSTRACT Compression molding can be used to fabricate polymer composites with long-, short- and intermediate-length fibers. In-line compression molding reduces cycle time through a single-step process in which fibers are directly introduced into the molten polymer in the extruder which is directly molded. It eliminates additional stage of heating and processing and hence is preferred in industries. This paper deals with the influence of fiber type and direction, coupling agent, spindle speed, feed rate, drill material and diameter on delamination and thrust force in in-line compression molded jute/polypropylene. Thrust force was greater in the specimens with 30 wt% long fiber, in longitudinal direction processed without coupling agent and drilling with high-speed steel drill. Delamination was severe in chopped fiber composites, in longitudinal direction processed without coupling agent and with cobalt-high-speed steel tool. Effect of speed, feed, drill diameter and tool material was analyzed using ANOVA, signal-to-noise ratio and Grey relational analysis. Residual tensile strength reduced by 24.7% in the composites drilled using the optimized parameters.

A simple all-fiber comb filter based on the combined effect of multimode interference and Mach-Zehnder interferometer

A polarization-dependent all-fiber comb filter based on a combination effect of multimode interference and Mach-Zehnder interferometer was proposed and demonstrated. The comb filter was composed with a short section of multimode fiber (MMF) fusion spliced with a conventional single mode fiber on the one side and a short section of a different type of optical fiber on the other side. The second type of optical fiber is spliced to the MMF with a properly designed misalignment. Different types and lengths of fibers were used to investigate the influence of fiber types and lengths on the performance of the comb filter. Experimentally, several comb filters with free spectral range (FSR) values ranging from 0.236 to 1.524 nm were achieved. The extinction ratio of the comb filter can be adjusted from 6 to 11.1 dB by varying polarization states of the input light, while maintaining the FSR unchanged. The proposed comb filter has the potential to be used in optical dense wavelength division multiplexing communication systems.

Influence of fiber type and content on freeze-thaw resistance of fiber reinforced lime stabilized clay

In this paper, a comparison of influences of freeze-thaw action on lime stabilized basalt and polypropylene fiber reinforced clay was investigated. Specimens including 12 mm basalt and polypropylene fiber at 0, 0.5 and 1% contents by weight were compacted under standard Proctor effort at their optimum moisture contents. Some of the fiber-clay mixtures were stabilized with 3% of lime, the rest of specimens were free of lime, for comparison. All specimens were cured for 28 days in a moist room (relative humidity is 95 ± 2%) at an average temperature of 20 °C. After curing, specimens were subjected to 0, 1, 3, 7 and 10 cycles of freeze-thaw tests following ASTM procedure. A series of unconfined compression and ultrasonic pulse velocity tests were performed. Test results showed that increased application of freeze-thaw cycles caused a decrease in unconfined compressive strength and ultrasonic pulse velocity of all specimens. A linear correlation was observed between unconfined compressive strength and ultrasonic pulse velocity values. Besides, loss of mass in specimens after being exposed to freeze-thaw action was evident. Considering freeze-thaw resistance, it was understood that polypropylene fiber is more effective in comparison with basalt fiber against freeze-thaw action.

Influence of fiber type on the impact response of titanium-based fiber-metal laminates

This investigation examines the influence of fiber type on the failure of titanium-based fiber metal laminates (FMLs). Two types of FMLs, comprising fiber-based composite layers, sandwiched between titanium sheets, were subjected to impact by a 12 mm steel sphere at various velocities ranging from 100–400 m/s. The first FML incorporated carbon fiber reinforced plastic (CFRP) layers, whereas the second had hot-pressed ultra-high-molecular-weight polyethylene fiber (UHMWPE, Dyneema®HB50) layers as the sandwiched component. FML specimens were clamped between annular plates, which exposed a circular target, and impacted at the center by spherical projectiles. Optical images of the deformation and failure induced in the two types of FMLs were captured by a high-speed camera, and the respective responses compared; the ballistic limit and energy absorbed were also determined. The results indicate that the ballistic performance of the Ti/HB50 system is superior to the Ti/CFRP combination, in terms of ballistic limit and energy absorption. However, this difference diminishes when the impact velocity exceeds 1.5 times the ballistic limit. The rolling direction of the titanium sheet plays a significant role in the amount of energy absorbed, through its influence on the deformation/failure mode of the FMLs.

Influence of fiber type and fiber orientation on cracking and permeability of reinforced concrete under tensile loading

During the service life of structure, cracks developed due to various internal or external stresses. These cracks offer a preferential path for the ingress of water, gas and aggressive ions through the concrete. This increase of concrete's permeability promotes the structure deterioration. A good understanding of structure permeability is thus required to design durable structures. An innovative permeability device was used to measure the impact of fiber orientation and fiber type on the water permeability of high performance fiber reinforced concrete (HPFRC) tie-specimens submitted simultaneously to a uniaxial tensile loading. Specific casting techniques provided tie-specimens with three fiber orientations (favorable, average and unfavorable) that can be found in fiber reinforced concrete (FRC) structural elements. Experimental results showed average fibers angles relative to the loading direction of tie-specimens of about 39°, 42° and 54° respectively for the favorable, average and unfavorable orientations. As fiber orientation become less favorable (from 39° to 54°), the tensile strength (ft) of characterization specimens reduced up to 33%, while the increase in permeability (Kw) tie-specimens achieved 1990% at fixed load and 600% at fixed stress in the rebar. For HPFRC casted with the same procedure, synthetic fibers provided a lower efficiency to control cracking at material and structural scales, and to limit water permeability in comparison to steel fibers. The impact of fiber orientation is clearly more significant on water permeability of HPFRC than on their mechanical behavior. These results provides insights of the impact of fiber orientation on durability of reinforced FRC structures.

Fibers and fiber cocktails to improve fire resistance of concrete

Our study was directed to improve the residual flexural strength and the heat-resistant properties of concrete exposed to high temperatures using different fiber cocktail loadings including steel, polymer or cellulose fibers. At first the morphology and the thermal properties of the fibers and the fiber/cement composites were investigated by SEM and TG/DTA-MS. Then the influence of fiber type and amount on residual flexural strength was tested after cooling back from 150, 500 or 800 °C temperature loadings. By adding steel, cellulose and polymer (polypropylene) fibers to cement, improvements both in post-cracking residual flexural strength and in insensitivity against explosive spalling were reached.

Influence of fiber type and content and amino acid levels in the sow lactation diet on farrowing process, sow health, and piglet vitality

Influence of fiber type and content and amino acid levels in the sow lactation diet on farrowing process, sow health, and piglet vitality

Influence of Fibre Type and Fibre Volume Fraction on Dynamic Properties of Slurry Infiltrated Fibre Concrete

The effect of fibre type and fibre amount on physico-mechanical properties of slurry infiltrated fibre concrete (SIFCON) at both quasi-static and dynamic load was evaluated experimentally. SIFCON is a special type of cement-based composite with high fibre volume fraction, extremely strong and ductile. Test specimens were prepared with 7 types of steel fibres (with different shape and mechanical parameters) in four volume fractions (7.5-15 vol. %). High performance fibre-reinforced concrete (HPFRC) has also been cast and tested for comparison purposes. The impact test has been carried out by using an in-house manufactured impact testing machine based on drop test principle. The test results revealed that SIFCON slab with 15 vol. % fibre content exhibits superior energy-absorption characteristics when compared to other slab specimens. Diameter of the fibres plays an important role for both strength and energy absorption capacity of SIFCON - using of low-diameter fibres with higher aspect ratio leads to the best results.

Rheological properties of molten flax- and Tencel®-polypropylene composites: Influence of fiber morphology and concentration

The rheological properties of short fiber reinforced polypropylene were investigated. Flax and Tencel® are two cellulose based fibers used in this study. Flax fibers are extracted from the bast of plants. They are composed of thin elementary fibers and rigid thick bundles made of elementary fibers “glued” together. Tencel® is a man-made cellulosic fiber spun from cellulose solution, with a uniform diameter, thin, and flexible. First, fiber dimensions before and after compounding were analyzed. Both types of fibers were broken during compounding. Flax shows larger length and diameter than Tencel®, but aspect ratio of flax is smaller. The reason is that after compounding flax remained in bundles. Dynamic viscosity, elastic and viscousmoduli were studied as a function of fiber type, concentration (from 0 to 30 wt. %), and composite temperature (from 180 to 200 °C). All Tencel®-based composites showed higher apparent yield stress,viscosity, and moduli compared to flax-based composites at the same fiber concentrations. The results are analyzed in terms of the influence of fiber type, aspect ratio, and flexibility. The importance of considering fiber morphology is demonstrated as far as it controls fiber flexibility and fiber-fiber interactions.

Process Parameters Optimization of Needle-punched Nonwovens for Sound Absorption Application

This paper reports a study on the optimization of process parameters of needle-punched nonwoven fabrics for achieving maximum sound absorption by employing a Box-Behnken factorial design. The influence of fiber type, depth of needle penetration, and stroke frequency on sound absorption properties were studied. These parameters were varied at three levels during experimental trials. From multiple regression analysis, it was observed that the depth of needle penetration alone was the most dominant factor among the selected parameters, which was followed by the interaction between depth of needle penetration and stroke frequency. Fiber type was the least dominant parameter affecting sound absorption. A maximum sound absorption coefficient of 0.47 was obtained from the selected parameters. The results showed that for a process such as needle-punching, which is influenced by multiple variables, it is worthwhile to study the interactive effects of process parameters for achieving optimum sound absorption.

Analysis of influence of fibre type and orientation on dynamic properties of polymer laminates for evaluation of their damping and self-heating

Abstract In the following study, the dynamic behaviour of polymer laminates reinforced by glass and carbon fibres with different orientations was considered for several excitation frequencies and elevated temperatures. The obtained dynamic moduli, loss factors and glass-transition temperatures were used for the evaluation of damping capabilities and the self-heating phenomenon. In order to evaluate the influence of a fibre type, additional studies for a pure matrix were carried out and used in the analysis as the reference. The obtained results show significant differences both in thermal and dynamic mechanical properties with respect to a fibre type and its orientation, which has a direct influence on the analysed self-heating and damping phenomena. The results of the present study could be used for the design of composite properties with respect to thermal degradation resulting from coupled thermomechanical loading conditions. Several hypotheses on the influence of a heating rate on estimation of the thermomechanical properties as well as structural degradation of composites in such conditions were presented with appropriate discussion and argumentation. The present study has a preliminary character. Furthermore, it is planned to perform such tests for specimens with a low cross-linking degree in order to analyse its influence on the resulting thermomechanical response of fibre-reinforced composite structures.

Experimental investigation on the thermal protective performance of nonwoven fabrics made of high-performance fibers

In this study, the thermal protective performance of nonwoven fabrics made of Nomex (polyisophthaloyl metaphenylene diamine), PPS (polyphenylene sulfide), P84 (polyimide), and basalt fibers was investigated. The objective was to determine the influence of fiber type, thickness of fabric, and wet on the thermal protective performance of nonwoven fabric. The thermal resistances of different nonwoven fabrics were measured using a dry hot plate instrument, the basalt nonwoven fabrics had a highest thermal resistance in all fabric, and the thermal resistance of nonwoven fabric increased with the increase in thickness. The six nonwoven fabrics were exposed to a hot environment for a few minutes by using a self-designed apparatus. The test results showed that the nonwoven fabrics made with basalt fiber exhibited the best thermal protective performance, and the thermal protective abilities of nonwoven fabrics increased with fabric thickness. Interestingly, nonwoven fabrics with added water were found to be able to keep the fabric surface lower temperature compared to dry fabrics when exposed to a hot environment, indicating the excellent thermal protective performance of wet nonwoven fabrics.

Quantitative Evaluation of Optical Fiber/Soil Interfacial Behavior and Its Implications for Sensing Fiber Selection

An adequate understanding of the interface between optical fibers and geomaterials is a prerequisite for applying distributed optical fiber sensor systems to strain monitoring in geoengineering. This contribution reports a quantitative investigation of the fiber/soil interfacial behavior regarding the influence of fiber types and normal pressures. A simplified model describing the progressive failure of a fiber/soil interface was briefly illustrated. Results of a series of pullout tests on three different soil-embedded optical fibers under various normal pressures were interpreted by this model, through which the fiber/soil interfacial behaviors were quantified. The results showed that the mechanical properties of the three fiber/soil interfaces were similar. Optical microscopic images indicated that the soil particles and the fibers were merely loosely contacted. This led to the formation of a fiber/soil interface susceptible to the normal pressure: 1) the interfacial bond was tightened and 2) the deformation measurement range was widened under high normal pressures. Moreover, the criterion for selecting a strain sensing fiber for geoengineering applications was discussed in terms of interfacial bond, deformation measurement range, ratio of peak to residual interfacial shear strength, Young's modulus of fiber, and so forth. An assessment of the three fibers reveals that, for ground deformation measurement, each fiber has its own advantages as well as limitations. In field or laboratory applications, a combination of different types of fibers may obtain the best measurement results.

Control performance of paper-based blood analysis devices through paper structure design.

In this work, we investigated the influence of paper structure on the performance of paper-based analytical devices that are used for blood analysis. The question that we aimed to answer is how the fiber type (i.e., softwood and hardwood fibers) influences the fiber network structure of the paper, which affects the transport of red blood cells (RBCs) in paper. In the experimental design, we isolated the influence of fiber types on the paper structure from all other possible influencing factors by removing the fines from the pulps and not using any additives. Mercury porosimetry was employed to characterize the pore structures of the paper sheets. The results show that papers with a low basis weight that are made with short hardwood fibers have a higher porosity (i.e., void fraction) and simpler pore structures compared with papers made with long softwood fibers. RBC transport in paper carried by saline solution was investigated in two modes: lateral chromatographic elution and vertical flow-through. The results showed that the complexity of the paper's internal pore structure has a dominant influence on the transport of RBCs in paper. Hardwood fiber sheets with a low basis weight have a simple internal pore structure and allow for the easy transport of RBCs. Blood-typing sensors built with low basis weight hardwood fibers deliver high-clarity assays. Softwood fiber papers are found to have a more complex pore structure, which makes RBC transport more difficult, leading to blood-typing results of low clarity. This study provides the principle of paper sheet design for paper-based blood analysis sensors.

Flexural Characteristic of Rubberized Hybrid Concrete Reinforced With Steel and Synthetic Fibers

Abstract To enhance the low strain capacity and brittleness of concrete, several researchers have already reported on the mechanical properties of rubberized concrete, which lead to reduced environmental concerns, direct cost reduction, low unit weight, high toughness, and improved absorption of impact. However, to overcome the drawbacks of low flexural strength and the low stiffness of rubberized concrete and to improve the crack resistance, steel, or synthetic (polypropylene) fibers, or both, were added into the rubberized concrete in this study. Based on the flexural performance test according to ASTM C1018 and ASTM C1609, this study investigates the combination of crumb rubber, steel or synthetic fibers, or both, in zero-slump concrete mixtures used in the dry-cast production method for concrete pipes. A series of concrete mixes were examined with the variation of the fiber volume fraction (Vf) (steel: 0.17 % and 0.33 %/synthetic-polypropylene: 0.17 %, 0.33 %, and 0.52 %), and crumb rubber with different replacement ratios of 3 % to 20 % (by volume) for sand (fine aggregate) in the concrete mixture. Seventeen rubberized mixtures were developed by incorporating different dosages of steel and polypropylene fibers and their combinations. The influence of fiber type, dosages of fibers, and rubber are analyzed on the basis of experimental results. Results indicate that the effect of hybrid reinforcement using both steel and polypropylene fiber in rubberized concrete is considerable in terms of increase in both peak load and toughness. The specimen of hybrid fiber-reinforced rubberized concrete (HYFRC) with 44 lb/yd3 (0.33 %:Vf) of steel fiber, 8 lb/yd3 (0.33 %: Vf) of polypropylene fiber and 3 % of crumb rubber (replacement with fine aggregates) showed higher peak load, modulus of rupture, and toughness than other mixtures. However, excessive replacement of rubber into the specimens had a negative effect on the flexural properties (strength and toughness).

Ductility improvement of cementitious composites reinforced with polyvinyl alcohol-polypropylene hybrid fibers

This paper investigated the hybridization effect of two chemically different fibers on the flexural behavior of cementitious composite. On this basis, polyvinyl alcohol and polypropylene fibers (polyvinyl alcohol/polypropylene fiber ratios: 75/25%, 50/50%, 100/0% and 0/100%) at different fiber volume fraction contents (1.2% and 2%) were considered as the variables. This study is especially focused on the influence of fiber types and their hybridization on composite deformability. The composite samples are subjected to the three-point bending test after 28 days of curing. The results showed that the fibers increased the flexural strength and ductility of cement matrix. It is revealed that the toughening improvement mechanism of polyvinyl alcohol and polypropylene fibers in cementitious composites are extremely different. Hybridization of polyvinyl alcohol and polypropylene fibers caused no significant improvement on flexural strength, but the strain capacity of composite under flexural load was increased. Finally, it was observed that the replacement of polyvinyl alcohol fiber with 25% volume fraction of polypropylene fibers can be considered as an important method for improving ductility of engineered cementitious composites.