Different Kinds Of Fibers Research Articles

A Review on Flame Retardant Finishing on Different kinds of Fibers

A Review on Flame Retardant Finishing on Different kinds of Fibers

Effects of Resistant Starch Infusion, Solely and Mixed with Xylan or Cellulose, on Gut Microbiota Composition in Ileum-Cannulated Pigs.

Fermentation of dietary fiber (DF) is beneficial for gut health, but its prebiotic effects are often impeded in the distal large intestine because of the fast degradation of fermentable substrates. One way to enhance the prebiotic effect of DF is to deliver fibers to the lower parts of the gut, which can be achieved by mixing different kinds of fiber. Therefore, in the present study, an ileum-cannulated pig model was employed to investigate the fermentation influence in the large intestine by infusing resistant starch solely (RS, fast fermentable fiber) and mixing with other fibers (xylan or cellulose). Twenty-four ileum-cannulated growing pigs were divided into four groups: one control group receiving saline ileal infusions and three experimental groups infused with RS, RS with xylan, or RS with cellulose. Fecal and plasma samples were analyzed for gut microbiota composition, short-chain fatty acids (SCFAs), and blood biochemistry. Results indicated no significant differences between the RS and control group for the microbiome and SCFA concentration (p > 0.05). However, RS combined with fibers, particularly xylan, resulted in enhanced and prolonged fermentation, marked by an increase in Blautia and higher lactate and acetate production (p < 0.05). In contrast, RS with cellulose infusion enriched bacterial diversity in feces (p < 0.05). Blood biochemistry parameters showed no significant differences across groups (p > 0.05), though a trend of increased glucose levels was noted in the treatment groups (p < 0.1). Overall, RS alone had a limited impact on the distal hindgut microbiota due to rapid fermentation in the proximal gut, whereas combining RS with other fibers notably improved gut microecology by extending the fermentation process.

A new biocomposite material mixing past and present to look toward the future

In the last decades interest of researchers in the field of vegetal fiber-based biocomposite materials to be used for structural strengthening has grown significantly. This interest is primarily driven by the plant fiber abundance, renewability, cost-effectiveness, historical-compatibility, and eco-friendly features. These positive aspects can be undermined by the variability of mechanical properties inherent in natural materials. Within this context, it seems interesting to consider the development of new biocomposite materials that involve the use of nanomaterials to enhance mechanical characteristics and to reduce material variability. This paper presents the preliminary results that will be used to assess the performance of biocomposites in structural strengthening of masonry structures, where the vegetal fibers are coated with nanomaterials. The base biocomposite is made of hydraulic lime mortar, enhanced with two different kind of fibers: Spanish broom and hemp fibers. Mechanical properties of these biocomposite materials are addressed experimentally by three-point bending tests and uniaxial compression tests. The results are compared to a reference material, made of classical hydraulic lime mortar, to investigate the best performances in the fiber- matrix bond. In particular, stress-strain curves are recorded to estimate maximum strength and strain together with a measure of fracture energy to assess the influence of natural fibers in the composite.

Impact resistance of geopolymer concrete under different types of fiber admixtures

To investigate the dynamic mechanical response characteristics of geopolymer concrete under impact load, the effects of different curing ages and strain rates on the impact resistance of geopolymer concrete have been explored. First, this paper first obtains the optimal mix ratio of geopolymer concrete by optimizing the slump test of mix ratio. Second, the stress–strain constitutive relationship of geopolymer concrete at different ages is deduced, and the mechanical properties, such as axial compressive strength and elastic modulus, are determined. Finally, two different kinds of fibers, carbon fiber and steel fiber, are mixed into concrete, which are utilized to test the mechanical properties including compressive strength, splitting tensile strength, flexural strength, and impact toughness. The results indicate that with the increase in carbon fiber content, the compressive strength, splitting tensile strength, and flexural strength of geopolymer concrete decrease first and then increase. Moreover, with the increase in steel fiber content, the compressive strength of geopolymer concrete increases continuously, the splitting tensile strength increases first and then decreases, the flexural strength decreases first and then increases, and the impact toughness increases first and then decreases.

Properties of recycled facemask fiber modified asphalt binder: Comparative analysis of surface modification and composite modification method

Polymer-modified asphalt binders had been developed as a novel strategy for road and building materials. People generally use disposable facemasks to reduce the risk of respiratory diseases during travel and commuting. These discarded masks will become a serious environmental problem. Recycled facemask has great potential application in the modified asphalt, but its modification effect of modified asphalt needs to be studied. In this work, different kinds of fibers and their modified asphalts had been successfully prepared and comparatively analyzed after the surface of fibers treated by butyl acrylate (BA) and further modified by copper oxalate (CO) nanoparticles. From the test results, the activation energies of polypropylene fiber extracted from recycled facemask (RPF) modified asphalt (RPA), treated RPF (MRP) modified asphalt (MRPA), and MRP further decorated with CO (MRPCO) modified asphalt (MRPCOA) were 64.08 kJ/mol, 59.09 kJ/mol, and 62.32 kJ/mol, respectively. MRP and MRPCO were better dispersed in asphalt than RPF. MRPA performed a lower value of the viscoelastic than RPFA, but MRPCOA performed the higher value of viscoelastic than MRPA. Compared with RPA, the short-term aging factors of MRPA and MRPCOA decreased by 31.73% and 53.18%, while long-term aging factors of MRPA and MRPCOA decreased by 11.34% and 12.31%. From the nanoindentation data, the maximum depth of MRPA increased by 5.23% and the hardness decreased by 2.55% than RPA. The maximum depth of MRPCOA also decreased by 6.68% and its hardness also decreased by 4.45% than MRPA. These results indicated composite modification of RPF performed better than only surface modification based on the viscoelastic and aging properties of modified asphalts. It provided a meaningful study for the potential applications of various recycled polymeric fibers in modified asphalt binder in the future.

Effect of compounding conductive materials on the mechanical properties of concrete and the microscopic mechanism

After adding conductive materials into the concrete matrix, cracks can be monitored in real-time through the change of concrete resistance when cracking. However, adding conductive materials will affect the working and mechanical properties of concrete. Therefore, this paper studied the influence rule and failure characteristics of the addition of conductive materials such as steel fiber and nanocarbon black on the mechanical properties of concrete. Combined with the performance index of the mix, it comprehensively determined the optimal dosage range of different types of steel fiber and nanocarbon black under the single mixing factor. Then, the orthogonal test method of three factors (different kinds of fiber, different contents of steel fiber, and different contents of nano carbon black) at four levels are used to test and study the mechanical properties of concrete. Through the analysis of the test results, the primary and secondary factors of conductive materials affecting the strength of concrete and the optimal dosage are obtained, and the failure mechanism is analyzed from the microscopic level. Finally, a structural model of the cracking resistance mechanism of conductive materials is proposed.

Dry sliding wear characteristics of natural fibre reinforced poly-lactic acid composites for engineering applications: Fabrication, properties and characterizations

Natural fibre composites have emerged as a viable alternative to conventional polymer composites, after environmental concerns gain popularity. In recent years, a tremendous growth in the applications of natural fibre composites have been observed, particularly in the field of construction, as well as aerospace and automotive industries. The present study investigates the feasibility of developing a novel tribo-material by reinforcing biopolymer with easily accessible and inexpensive plant fibres from the surroundings. The fibres were treated chemically prior to fabrication. The injection molding process was used to fabricate laminated composites by incorporating three different kinds of fibres (sisal, banana, and bagasse) into Poly-lactic acid (PLA) matrix at 10% and 20% fibre concentrations. Wear properties of fabricated composites were studied on a digital display controlled pin-on-disc test rig. The test parameters under dry sliding conditions were sliding distance (1000–3000 m), sliding speed (2,4 and 6 m/s) and applied load (10 N). The experimental results depict that the incorporation of natural fibres improved tribological properties of neat PLA matrix. The worn surfaces of developed composites were examined using a scanning electron microscope to study the wear mechanism.

Research on fiber reinforced concrete and its performance prediction method and mix design method

To better solve the problems of performance prediction and mix design of fiber reinforced concrete (FRC), this paper carried out relevant research based on different kinds of fibers. First, according to the existing results and experimental research, fibers of various scales are selected preliminarily. Then, based on the mechanical property test, the fiber selection, fiber content and fiber hybrid mode are studied, and the fiber action mechanism is revealed through the failure process analysis and microscopic observation. Then, based on the newly constructed fiber reinforcement factor (S), a FRC strength prediction model was established. Finally, by combining S with hybrid fiber effect coefficient (RH) based on comprehensive properties, a method for FRC mix design is formed. The research results and conclusions are as follows: Steel fiber (SF), Short macroscopic polyvinyl alcohol fiber (SMP), fine polyvinyl alcohol fiber (PVA) and Calcium carbonate whisker (CW) have better performance improvement effects in their respective scales, and the content of SF, SMP, PVA and CW with the highest cost performance ratio is 2%, 0.75%, 0.5% and 1% respectively. Micro observation shows that CW not only has the effect of “micro filler” and “microfiber”, but also has the effect of friction resistance at the interface between reinforcement fiber and substrate. According to the mechanical property data and RH value, the best sample group is the sample containing 1.5% SF, 0.5% SMP and 1% CW. In addition, 1.5% SF and 0.5% SMP can also produce good performance when mixed with 1% CW respectively. The regression analysis results show that the FRC strength prediction model established in this paper has good regression coefficients. The mix design method of FRC based on S and RH can provide reference for the research and production of FRC.

Low temperature performances of fiber-reinforced asphalt mixtures for surface, binder, and base layers

In the present study, the effects of adding fibers and Reclaimed Asphalt Pavement (RAP) on the low temperature performances of open graded asphalt mixtures for surface layer and dense asphalt mixtures for surface, binder, and base layers were investigated. Two different kinds of fibers were used: a combination of aramid and polyolefins fibers were utilized for preparing fiber reinforced porous asphalt mixtures, while polyacrylonitrile fibers were employed for producing conventional dense asphalt mixtures for surface, binder, and base layers. Reference mixtures were made with virgin materials as a benchmark to study the effects of the fibers' addition. Moreover, asphalt mixtures for surface layers composed of 30% RAP and mixtures for binder layers containing 50% RAP were produced to study the combined effects of fibers and RAP on the low temperature's performance. Thermal Stress Restrained Specimen, Uniaxial Tension Stress, and Semi-Circular Bending tests were used to evaluate the response against thermal distresses. The addition of the fibers showed no significant effects on the low temperature strength, while a remarkable improvement in the failure temperature and crack propagation resistance properties was found. The use of fibers has also shown to be beneficial in combination with mixtures designed with RAP and higher binder content suggesting a dedicated study on mix design for future research.

Analysis of Rejuvenating Fiber Asphalt Mixtures' Performance and Economic Aspects in High-Temperature Moisture Susceptibility.

Non-renewable resources such as natural stone and asphalt are in short supply. Recycling technology, with its lower cost, has been used as the primary approach to asphalt pavement maintenance engineering. The inclusion of reclaimed asphalt pavement materials in producing new asphalt pavements may increase the risk of cracking. The strength and toughness of the asphalt mixture can be reduced. In this study, Hamburg wheel tracking tests (HWTT) were performed on rejuvenated asphalt mixtures with distinct maintenance processes. Different kinds of fibers have been used as additives to reinforce the rejuvenated asphalt mixtures. The HWTT rutting curve was identified as having three stages, including the post-compaction stage, the creep stage, and the stripping stage. The three-stage rutting curve model was used to determine the intersection point between the creep stage and stripping stage. The other two feature points (i.e., the post-compaction point and the stripping inflection point) were redefined with a new calculation method. Then, the rutting effect and stripping effect were separated with these feature points. The performance and economic benefits of fiber-reinforced rejuvenated asphalt mixtures were investigated through grey correlation analysis under the three maintenance processes. The feature points of the HWTT curve and the cost of the corresponding maintenance process were selected as the impact factors. Finally, the optimal scheme was developed by analyzing the influence of each factor on both performance and economic benefits.

Performance enhancement of 8 channel SCM–WDM based RoF link using different type of transmission fibers along with different type of channel spacing

Abstract A system is represented that uses 20 nm of channel spacing and unequal channel spacing along with four different types of transmission fibers on subcarrier multiplexing–wavelength division multiplexing (SCM/WDM) based radio over fiber (RoF) link. These five different kinds of fibers have been analyzed offering different propagation parameters. In case of 20 nm of channel spacing the performance of the link is improved by 35.32% with the use of True wave fiber. In this paper, 8 channel SCM–WDM based RoF based model is simulated and analyzed with different type of optical fibers covering distance of 10 km. A comparison of Q-factor at different optical power and different optical lengths has been made. Q-factor, bit error rate and eye diagrams have been examined for assessing the performance of the model.

Multiscale embedded models to determine effective mechanical properties of composite materials: Asymptotic Homogenization Method combined to Finite Element Method

A reliable way to determine the effective properties of heterogeneous media plays an important role in engineering design. As an experimental test to obtain effective properties may be tedious and expensive to perform, and as computational approaches, when all heterogeneities of the media are considered during the simulations, might become impractical due to computational effort, homogenization procedures are a good alternative to estimate the effective properties of the media, mainly considering damage and manufacturing defects in the material. Among several homogenization methods, the Asymptotic Homogenization Method (AHM), a well-established mathematically based method, is considered for deriving the relations for the effective properties of the media, and the Finite Element Method (FEM) is used to solve the equilibrium relations. In this work, a fiber-reinforced composite is considered, with three different regions depicted: intact, damaged fibers, and regions with resin/void pockets. The proposed AHM-FEM approach is used to simulate a tensile test in all scenarios with standard and multiscale embedded Unit Cells used to obtain the effective elastic modulus on the fiber direction. Discussions regarding computational efficiency are carried out, as well as numerical comparisons among the types of Unit Cells used to model the media. In a second scenario, the complete fourth-order elasticity tensor of the media is investigated, considering the fibers as both isotropic and transversely isotropic. The results for the transversely isotropic fibers approach literature data, while when isotropic fibers are considered, poor results are achieved. Finally, the approach is extrapolated to obtain the mechanical properties of metamaterials, defined here as a composite reinforced by two different kinds of fibers.

A Multi-Analytical Approach to Investigate the Polychrome Clay Sculpture in Qinglian Temple of Jincheng, China.

This article presents an integrated analytical method to investigate the polychrome clay sculptures of the Qinglian Temple in Jincheng City, Shanxi Province, China. Digital microscopy, SEM-EDS, XRD, Herzberg stain, Micro-Raman spectroscopy and FT-IR were selected to identify the raw materials and techniques used to produce the ground clay layer, the white powder layer and the mineral pigment of the polychrome clay sculptures. The investigation shows that the clay used to make the coarse and fine clay layer is consistent. However, different kinds of fibres were found mixed in the coarse and fine clay layers: wheat straw was the main fibre used in coarse clay layer, while the bast fibres, including ramie, kenaf and sisal hemp, were used as the fibre supports in the fine clay layers due to their useful properties. The white powder layer was made of a mixture of kaolinite and gypsum. For the mineral pigments, it principally contained red (hematite, minium or a mixture of minium and cinnabar), green (atacamite and atacamite), blue (azurite), yellow (yellow ochre), black (amorphous carbon) and white (the mixture of kaolinite and gypsum). Additionally, a gilding technique and multiple paint layers also typified many pigment areas. This work has furthered understanding of the materials and techniques used in making the sculptures of the Qinglian Temple and has clear implications for the restoration and conservation treatments on these kinds of ancient painted clay sculptures.

A scientometric review on mechanical and durability performance of geopolymer Paste: Effect of various raw materials

• An extensive review on geopolymer paste (GPL) for mechanical and durability behavior. • Microstructural assessment of fly ash (FA) and FA-slag GPL paste. • Assessment of different properties of GPL for various raw materials. • Assessment of durability performance of GPL for various raw materials. Geopolymer (GPL) paste has recently become a promising ecological substitute for conventional cementitious composites. They are environmentally friendly and cost-effective, and their manufacture involves a relatively small amount of energy. GPL is alkali-activated pastes made up of base materials that can be utilized for concrete structures, ensuring environmental sustainability and enabling cost-effective construction. This research assesses the microstructural aspects of fly ash (FA) and FA-slag GPL paste, fresh characteristics including workability and setting time, hardened characteristics including compressive strength (CS), and splitting tensile strength (STS), and durability characteristics. The influence of various forms of alkaline solution, the concentrations of alkaline solution, the integration of various kinds of alkaline activators, the alkaline solution to the binding material ratio (S/B), the ratio of fine aggregate to binding material, curing duration and temperature, and the influence of multiple kinds of superplasticizers are investigated. The current work also examines the influence of several additives in FA-GPL and FA-slag GPL pastes, including nano-materials, different kinds of fibers, bio-additives, epoxy, alumina, quartz powder, alccofine, and silica fume (SF). The influence of mix proportioning on the durability, hardened, and fresh features of FA-GPL and FA-slag GPL mix was comprehensively discussed in this work. The conclusions of the reviewed research papers are reported comprehensively.

ENHANCING OF FLEXURAL STRENGTH OF WEB OPENING REINFORCED GEOPOLYMER BEAMS BY USING FRP STRIPS

This study is devoted to inspect the flexural behavior of Geopolymer reinforced concrete beams with “large” web transverse opening and strengthened by three kinds of Fiber Reinforced Polymer materials. The implemented experimental program comprised casting eight beams under static and “one stage” repeated load, two of these are normal concrete beams and the others are Geopolymer beams. These beams are divided into two groups, the first comprised four beams of solid and beams “with transvers web opening” under static load for normal and Geopolymer concrete beams. The second group are of four Geopolymer beams that one of them is “un strengthened and having transvers web opening” while the others are also have transvers web opening but strengthened by different kinds of Fiber Reinforced Polymer materials sheets that installed vertically aligned and accompanied with the 90mm diameter large circular web opening. The strengthening materials included are Carbon Fiber Reinforced Polymer, Glass fiber Reinforced Polymer and Hybrid (one layer of Glass + one layer of Carbon) reinforced polymer sheets. The results showed that for the ultimate load capacity was decreased by 9.96% for holed normal concrete beam if compared with solid normal concrete solid beam while such capacity was decreased 2.25% and 11.89% for solid and holed Geopolymer beams respectively. In addition to that, the maximum load capacity is also decreased by 8.16%, 10.20% and 12.25% for Glass, Carbon and Hybrid fiber reinforced polymer strengthened beams if compared with reference beams “holed un strengthened beam” subjected to cyclic load.

Performances of novel poly(diaryloxyphosphazene) based heat shielding materials with various fibrous reinforcements

AbstractElastomeric heat shielding materials (EHSMs) are necessary to protect combustion chambers of solid rocket motors during their working. Poly(diaryloxyphosphazene) (PDPP) elastomers own inherent thermal stability and flame retardancy because the backbone of alternating phosphorus and nitrogen atoms can be a novel promising polymer matrix toward EHSMs. The present study deals with the development of a novel PDPP based EHSMs with several different fibrous reinforcements, including Kevlar, polyimide, and carbon short fibers. It is found that PDPP/Kevlar composites show outstanding tensile strength and ablation resistance because of their strong interfacial bonding between matrix and fibers which benefits from the possible network of intermolecular hydrogen bonds. PDPP/carbon composites produce a compact charred layer due to their high char yields of carbon fibers. These results improve the understanding of the role of polyphosphazenes with different kinds of fibers on ablation mechanisms, which enable the possibility to exploit intrinsic properties of polyphosphazenes.

Structural behavior of GFRP reinforced recycled aggregate concrete columns with polyvinyl alcohol and polypropylene fibers

The objective of this research study is to demonstrate the axial compressive behavior of GRFC columns by fabricating five circular columns (1150 mm high and 250 mm in cross-section) and testing them under axial concentric loading. Two different kinds of fibers, that is, polyvinyl alcoholfibers (PVA) and polypropylene fibers (PPF) were incorporated into the concrete. Two types of transverse confinement (GFRP hoops and GFRP spirals) were provided. The efficiency of GFRP hoops was explored by providing them at the spacing of 75 mm, 150 mm, and 250 mm, respectively. The efficiency of GFRP spirals was examined by keeping the spacing of 38 mm and 75 mm, respectively. The GRFC columns confined with GFRP spirals portrayed higher axial strength and higher ductility indices. Furthermore, an extensive finite element modeling (FEM) was performed by considering the effect of hybrid fibers using a modified concrete damaged plastic (CDP) model. The proposed FEM captured the axial response and cracking behavior of GRFC columns with high accuracy. This study also proposed a new empirical model for capturing the axial strength of GRFC columns by considering the influence of GFRP bars and lateral confinement of GFRP hoops/spirals.

A review on hybrid fiber reinforced concrete pavements technology

The problems of soil-structure interaction involve different members or different materials behave together under applied loading. In the case of concrete pavement resting on soil under traffic loading, both concrete and soil will deform. Rigid Pavements are made of Portland Cement Concrete (PCC). It serves out two aims, to maintain a durable surface with comfortable driving for vehicles. The second purpose is to decrease the stresses on the layers of pavement beneath the surface such as subbase and subgrade. Concrete is considered a weak material in resisting tensile stresses. Therefore, when low tensile stresses are applied, rigid pavement begins to crack effortlessly. In concrete pavement, the usage of different kinds of fiber reinforcement could be an effective technique to improve these properties. Numerous kinds of fibers are utilized in the concrete pavement to behave as an alternative to ordinary reinforcement. They may differ in material like steel or plastic and could be in many shapes, and dimensions. The addition of fibers is during the mixing when the concrete is still fresh. The incorporation of different sorts of fibers could be a significant step in diminishing the cracks and achieving a higher performance of concrete. Two kinds of fibers or even more than two can be combined to achieve a mixture that produces profits for each type of fiber in this composite. In this paper, an intensive review was made to demonstrate the forms of distresses that could happen in concrete (rigid) pavement and the impact of incorporating different kinds of fibers into the concrete to enhance the concrete ability to eliminate or even delay the process of failure.

Measurement of phase and group refractive indices and dispersion of thermo-optic and strain-optic coeffients of optical fibers using weak fiber Bragg gratings.

In this work we report on the measurement, with record accuracy, of the absolute modal effective refraction index (phase index) of single-mode optical fibers by using Bragg gratings. We also demonstrate a new method to measure the group index of the fibers from the grating's Bragg wavelength. We present as well the characterization of the thermo-optic and strain-optic coefficients as a function of the wavelength; the values we have obtained are the closest to those of pristine fiber measured with gratings technology so far. The phase index is measured with a set of gratings in the wavelength ranges from 1509 to 1563 nm, and the group index is obtained from the wavelength dependence of the phase index. Very weak gratings with reflectivity down to 10-3 have been used in order to minimize the perturbation of the pristine fiber. Results are presented at a temperature of 22°C and zero strain after preliminary calibration of the thermo-optic and strain-optic coefficients as a function of the wavelength. Accuracies better than 3×10-5 and 7×10-4 have been achieved for the phase and group indices, respectively. It is also shown that the main source of error relates to the uncertainty in pitch of the phase masks used for grating inscription. The technique is useful for testing different kinds of fibers including telecommunication, amplifying, and polarization maintaining.

Finite element analysis of flexural performance of different fiber reinforced recycled concrete beams

In this paper, the influence of different kinds of fiber on the mid-span bending moment and deflection of the regenerated concrete beam under the initial cracking and yielding state is studied by ANSYS finite element simulation analysis. The results show that different kinds of fibers have little influence on the mid-span bending moment of the regenerated aggregate concrete beam at the initial cracking, and have a great influence on the deflection value at the initial cracking, among which the reinforced effect is obtained in the group mixed with steel fiber. The mid-span bending moment and deflection of the trabeculae at the yield of the trabeculae are reduced by the addition of different kinds of fibers.