Iron Fibers Research Articles

Thermophysical Properties of Concrete Blended with Iron Powder and/or Iron Fibers

Abstract The use of iron waste in concrete is now of considerable importance, mainly because of the benefits for the environment and for improving the strength of concrete. The increased and unused of this industrial byproducts represents a challenge for the environment and human health. This article experimentally explores the influence of utilizing iron powder waste and iron fibers in concrete in order to enhance the thermophysical properties of concrete and reduce the environmental impact resulting from iron waste. The aim of this work is to study the thermophysical properties (thermal conductivity, volumetric heat capacity, thermal diffusivity and thermal effusivity) of concrete with waste iron powder and iron fibers for application in building construction. The iron powder waste was added to the concrete with different percentages of 0%, 5%, 15%, 20% and 25% respectively as a partial replacement of sand. The iron fibers were added with mix proportions including 1.0%, 1.5%, 2.0% and 2.5% by volume of concrete, and in two different arrangements, uniform and random. The thermal conductivity and the volumetric heat capacity of these samples were measured experimentally in the dry state at ambient temperature (20 °C), and at 28 days of age. The effect of the integration of iron powder and fiber on thermal properties was analysed.

Evaluation of Recycled Tyre Steel Fibres Effectiveness on the Properties of Concrete

Disposal of tire waste is a difficult task because tires are generally indestructible and have long lifetimes. Tire waste is managed via short-term solutions such as storing or dumping in illegal landfills. Tire recycling is a process where tires are recycled for reuse in vehicles; however, the recycled tires are not suitable for reuse because their recovery is difficult owing to faults such as holes. Thus, tires are the most problematic and largest source of waste owing to their high production and durability. Several tire recycling techniques that take advantage of various tire components have been implemented. This study focuses on the utilization of solid steel fibers are incorporated into a concrete tire frame. This is done to assess how well fibers work with reinforced concrete’s design. Additionally, concrete’s compressive strength was evaluated three times (0.1%, 0.2%, and 0.3%). The study’s findings are based on an examination of how tire-recycled steel fibers affect concrete strength and their use to enhance the strength of concrete. Concrete reinforcement with steel fibers results was compared with the traditional concrete reinforcement and it was found that the iron fibers present in the tires enhanced durability and strength of concrete.

Attapulgite coated polycrystalline iron fibers composites with light weight feature and enhanced microwave absorption properties

In this study, attapulgite coated polycrystalline iron fibers (ATP/IF) composites were prepared by layer-by-layer electrostatic self-assembly technology and aligned ATP/IF composite were prepared by shear-force. The complex permittivity decreases from 35 to 20 and permeability decreases from 1.3 to 1.15 at 2.6 GHz for ATP/IF-1 composite. Anisotropy electromagnetic properties were achieved by aligned ATP/IF composites. The microwave absorption properties show that broader bandwidth and better absorption efficiency were obtained by ATP/IF composite (the minimum RL values decrease to −35 dB, the absorption bandwidths with RL below −5 dB is 8.8 GHz at thickness of 1.8 mm for ATP/IF-4 composite), and the microwave absorption performance was further enhanced by aligned ATP/IF-1-A composite (the bandwidth increases to 7.5 GHz at thickness of 1.2 mm). Double-layer ATP/IF composite was designed and the microwave absorption performance show that broader bandwidth and better efficiency can obtained by adjusting the impedance matching characteristics and the absorption characteristics of ATP/IF composite. When d1 = 1.5 mm, d2 = 0.5 mm, the absorption bandwidth is 7.0 GHz from 7.0 to 14 GHz and the minimum RL value reach about - 30 dB, showing higher absorption efficiency and wider bandwidth compared to single-layer aligned ATP/IF composite. Lightweight absorbers with enhanced microwave absorption performance were obtained under a lower content of 40 wt% due to the ATP coating on the surface of IF and alignment of ATP/IF composites.

Investigation of Flexure Strength of Aluminum Composites Reinforced with Iron Fibers

Flexure strength of Aluminum composite reinforced with iron fiber has been investigated.Atomization procsses method were used to prepare sheet of aluminum reinforced with iron fiber with direction (0-90°) and (0-45°) to cognition fiber direction effect on flecture strength values.The results shows that the values of maximum bending stress, yield stress and young modulus of aluminum reiforced with iron fibers direction (0-90) higher than for the aluminum reinforced with fibers direction (0-45). The optical microscopy and photographic pictures shown the fracture surface of the tested specimens and fibers segmented and supported the rising in the flecture strength values of the aluminum composites(0-90).

Investigating the electromagnetic wave-absorbing, water repellency, and flame-retardant effectiveness of nickel–iron/PPTA-blended knitted fabrics

In recent decades, electromagnetic wave pollution has become more and more serious. In order to reduce the adverse effects of these waves, the nickel–iron/polymers of p-phenylene terephthamide (PPTA)–blended single yarn and plied yarn were manufactured, and the nickel–iron fibers with various contents (10%, 15%, and 20%) as raw materials were used. Nickel–iron/PPTA-blended yarns were knitted with three knit structures and three looped deep (11.25, 11.50, and 12.00 mm). The electromagnetic absorption effect was examined using the reflectance arch method at a frequency range between 2 and 18 GHz. The results show that the fabric with plied yarn, nickel–iron fiber content of 10%, looped deep of 12.00 mm, and loop notation of structure C has the best electromagnetic wave absorption performance, which can reach −30 dB reflectivity at 5.1 GHz, and the bandwidth with reflectivity lower than −5 dB reaches 2.5 GHz. In order to make the fabric obtain more functions, water-repellent treatment of the fabric is carried out. The results show that the best finishing effect can be obtained by using 40% water repellent and drying at 170°C for 5 min so that the sample can resist the hydrostatic pressure of 49.1 kPa. Finally, through the vertical burning test, the flame retardancy of the fabric can reach level B1.

Ultra-high stability and magnetic response of magnetorheological fluids based on magnetic ionic liquids and carbonyl iron fibers

A novel magnetic ionic liquid (IL) based on 1-methylethyl ether-3-butylimidazole cation and [FeCl4]− anion was synthesized for application as a carrier of magnetorheological fluids (MRFs). Stability and magnetic response of the MRFs were investigated as a function of the anion chemical structure and content of carbonyl iron fibers. The MRFs based on the magnetic ILs displayed better redispersibility, slower settling rates, and increased magnetic-induced stress compared with conventional MRFs based on oils or ILs. Furthermore, the mechanism of MRFs with good performance was investigated and proposed by molecular dynamic simulation. These results do not only confirm that the magnetic ILs are potential carriers of MRFs but also provide a new way to improve the stability and magnetic response of MRFs for various applications.

Behavior of reinforced geopolymer concrete flat slab exposed to high temperature

In this study, fifteen 700x500 mm concrete flat slabs made of geopolymer concrete were examined under concentrated to identify the maximum punching shear resistance under the influence of various factors such as steel fiber content, slab thickness, flexural reinforcement ratio, in addition to replacing 10% of metakaolin by silica fume under the influence of temperature increasing up to 300 oC in addition to testing ninty control specimens to investigate the mechanical properties. It was observed there was a beginning to change in the structural behavior when the temperature reached 100 oC due to an increasing in the pressure by the liquid vapor, then a important drop in the capacity and behavior when reaching the temperature 300 oC. The presence of iron fibers led to a decreasing in the distance between the edge of the column and the critical section, which reduced the punching shear values. Decreasing of the maximum and cracking of the punching shear were recorded at 37% and 42%, respectively, when the temperature increased to 300 ° C.

Three-Dimensional Fibrous Iron as Anode Current Collector for Rechargeable Zinc–Air Batteries

A three-dimensional (3D) fibrous structure with a high active surface and conductive pathway proved to be an excellent anode current collector for rechargeable zinc–air batteries (ZABs). Herein, a cost-effective and highly stable zinc (Zn) electrode, based on Zn electrodeposited on iron fibers (Zn/IF), is duly examined. Electrochemical characteristics of the proposed electrode are seen to compete with a conventional zinc/nickel foam (Zn/NF) electrode, implying that it can be a suitable alternative for use in ZABs. Results show that the Zn/IF electrode exhibits an almost similar trend as Zn/NF in cyclic voltammetry (CV). Moreover, by using a Zn/IF electrode, electrochemical impedance spectroscopy (EIS) demonstrates lower charge transfer resistance. In the application of a rechargeable ZAB, the fibrous Zn/IF electrode exhibits a high coulombic efficiency (CE) of 78%, close to the conventional Zn/NF (80%), with almost similar capacity and lower charge transfer resistance, after 200 charge/discharge cycles. It is evident that all the positive features of Zn/IF, especially its low cost, shows that it can be a valuable anode for ZABs.

Compressive strength and modulus of elasticity of concrete using iron fibers

This paper presents the effect of using iron fiber to the value of compressive strength and modulus of elasticity of concrete. The iron fibers used in the concrete mixture are 50 mm long and 5 mm wide which is the waste of the lathe. For this purpose, there are 5 variations of concrete mixture with iron fiber content of 0%, 6%, 8%, 10% and 12% of cement weight for each mixed variation. The test specimens used are cylindrical in diameter 150 mm and 300 mm in height. The value of fresh concrete slump is set in the range 100-140 mm. The value of compressive strength and modulus of elasticity of concrete was obtained from concrete cylinder testing after 28 days of curing. The test results showed that the concrete mixture with iron fiber content of 8% yielded the highest compressive strength from the variation of the mixture of concrete using iron fiber. The value of the modulus of elasticity of the concrete obtained from the test results shows the same trend with the elasticity value calculated using the empirical equation.

Electromagnetic and microwave absorption properties of iron pentacarbonyl pyrolysis-synthesized carbonyl iron fibers.

The present study executed iron pentacarbonyl pyrolysis to synthesize one-dimensional structured carbonyl iron fibers (CIFs) via carrier gas induced flow. The obtained CIFs with a diameter of 100–300 nm and length–diameter ratio of more than 20, are actually composed of a large number of nanocrystalline aggregates. We investigated the dependence of the structure, morphology, and static magnetic and electromagnetic properties of the CIFs on the pyrolysis temperatures. CIFs synthesized at 300 °C (denoted as CIF-300) exhibited optimal microwave absorption properties dependent on the fiber structure and well-matched impedance. An optimal reflection loss of −58.1 dB was observed at 13.8 GHz with a matching thickness of 1.43 mm. Furthermore, CIF-300 presented a broad effective absorption bandwidth (RL ≤ −10 dB) of 5.66 GHz with a thickness of 1.44 mm, indicating that it could be applied in practical applications from 3.74 GHz to 18.0 GHz by tuning its thickness from 1.0 mm to 4.0 mm. This paper not only reveals that the CIFs synthesized at 300 °C have great potential application in microwave absorbing materials (MAMs) with thin thicknesses, wide absorption bandwidths, and strong absorption intensities, but also provides a simple approach to prepare metal fibers.

Near Surface Characteristic: Hybrid Fiber Reinforced Concrete With Different Aspect Ratio

The present work is enhancement of near surface characteristics for hybrid fiber reinforced concrete (aspect ratio 40+100). Here in this research work an attempt has made to study water absorption values for different types of fiber reinforced concrete, which are having different aspect ratios like 40, 100 and 40+100. Concrete mix along with fibers are casted and cured for 28days. Both water absorption test and sorptivity tests carried on hardened concrete. The main objective is to check variation in absorption values due to addition of different types of fibers. Here totally five different types of fibers are considered like steel fiber, Galvanized iron fibres, High density polyethylene fibres, waste plastic fiber and polypropylene fibers Experimental investigation shows that except polyprolene hybrid mix concrete other hybrid mixes has showed good results. But as compared to mono fiber reinforced concrete hybrid fiber reinforced concrete has showed better results. This research was aimed to provide benchmark for future research works on near surface characteristics of hybrid fiber reinforced concrete.

Электропроводный материал на основе порошковой меди с повышенными механическими свойствами

The methods of pressing, rolling, and sintering in hydrogen at 800°C have been applied to production of powdered materials based on copper of the Cu–Fe–Al system. The influence of single components and their blends on compaction, structure, and main functional properties of composite materials—electrical conductivity, hardness, and strength (yield stress)—has been analyzed as a function of process variables: compacting pressure of 200–700 MPa, deformation by rolling of 40–85%, dispersity of iron powders having particle sizes <50 and 63–100 μm, contents of iron powder of 5–10 wt % and Fe2Al5 intermetallic powder of 2.5–5 wt %. The best combination of physicomechanical properties has been found for composite material with the composition (wt %) 92.5 Cu + 2.5 Fe2Al5 + 5 Fe, together with iron particle sizes of 63–100 μm. It has been demonstrated that dispersion strengthening of copper by Fe2Al5 particles and filling of its structure with iron fibers formed by rolling provides high relative density of 98–99% and subsequent strength properties of the composite material: hardness HB of 980 MPa, yield stress of 150 MPa at electrical conductivity of 71% of copper conductivity.

Microwave properties of the single-layer periodic structure composites composed of ethylene-vinyl acetate and polycrystalline iron fibers

A single-layer microwave absorbing structure composed of the ethylene-vinyl acetate (EVA) powders and polycrystalline iron fibers (PIFs) with thickness of 2 mm, which has a periodic array of circular hole, is designed and fabricated using the mechanical method. We show that the reflection loss (RL) can be easily adjusted by changing the geometric parameters. The maximum RL is 18.7 dB at 15 GHz, and the effective absorption bandwidth of 1.7 GHz for the diameter of circular hole is 10 mm, and enhanced to be 23.7 dB at 15.1 GHz with the corresponding bandwidth of 7.2 GHz when the diameter decreases to 5 mm. The measured absorption of the composite is in good accordance with the simulation results. Furthermore, the possible absorption mechanism of the composite has been discussed. Our results illustrate that the integration of frequency selective surface (FSS) with traditional PIFs can achieve a wide frequency range of a strong absorption.

Attenuation coefficients for fibrous self-compacting concrete in the energy range of 50-3000keV

The fibrous self-compacting concrete is a high performance concrete with uniformly distributed iron fibers, developed and characterized by Maragon (2006 and 2009). Transmission measurements, with 137Cs and 60Co sources were performed for the attenuation coefficients determination for both ordinary and fibrous self-compacting concretes. The results were compared to each other and to the values found in the literature for ordinary concrete. The mass attenuation coefficient for the fibrous self-compacting concrete showed to be higher than those for ordinary concrete of about 5%, depending on the gamma energy. However, it should be noted that the density of fibrous self-compacting concrete is higher than ordinary concrete, 2.4 g/cm3 and 1.9 g/cm3 respectively, increasing still further the difference in mass attenuation coefficient. In addition to that, by using Monte Carlo simulations, with MCNP5 Monte Carlo computer code, the data was extended to the 50-3000 keV gamma energy range.

The response of conductive-fiber reinforced composites to electric field

An analytical procedure, which couples electric, magnetic, thermal and mechanical effects is presented for the prediction of the response of unidirectional fiber-reinforced composites that are subjected to electric field, applied in the fibers’ direction. It is assumed that at least one of the phases of the composite (e.g., the fibers) is electrically conductive, and that all phases are thermally conductive. The composite is assumed to occupy a finite, symmetric domain which is discretized into a double array of subcells. The governing equations, with the interfacial and boundary conditions, are satisfied in the integral sense. The externally applied field generates electric current, which induces a magnetic field as well as temperature increase. The mechanical deformation of the composite results from the combined effect of the ponderomotive force, which is created by the magnetic field, and the temperature distribution within the constituents. The purpose of the present paper is three-fold. (a) To perform quantitative analysis of the model for the ponderoromotive force in deformable media. (b) To present computational strong-form treatment of the magneto-mechanical boundary-value problem in a composite. (c) To suggest a computational apparatus for deriving the response of a sensor/actuator excited by an applied electric field or electric field gradient. Application is given, presenting the magnetic, thermal and mechanical field distributions, as well as the macroscopic (global) response of a composite, which consists, for simplicity, of two iron fibers embedded in an epoxy matrix.

Modifying the structure and properties of Cu-Fe composites by the methods of pressure formation

In this survey, the results of the available studies are generalized and the effects of thermomechanical treatment on the structure and the magnetic, mechanical, and electrical properties of Cu-Fe composites produced by the methods of casting, powder metallurgy, and severe plastic deformation are analyzed. The primary attention is paid to the method of packet hydroextrusion, which makes it possible to achieve a wide spectrum of diameters (3 nm−2 mm) of iron fibers and of the amount of fibers (1–8 × 108) in these composites with varying volume content (10–60%). The physical mechanisms of the revealed effects of the structural modification of the physicomechanical characteristics on different scale (macro, micro, and nano) levels are discussed.

Electromagnetic interference shielding boards produced using Tetra Paks waste and iron fiber

Tetra Pak packages (Tetra paks) are one of typical paper/plastic/aluminum composites and widely used in soft drinks and dairy product markets. However, after its service life, serious environmental problems generate due to its non-biodegradable nature. In this paper, a novel electromagnetic interference (EMI) shielding board was developed using recycled Tetra paks waste with addition of iron fibers. The influence of fiber loading level, fiber length and number of iron fiber layer within the matrix on EMI shielding effectiveness (SE) and volume resistivity (VR) was investigated. The results indicated that fiber loading level, fiber length and number of iron fiber layer affected EMI shielding properties significantly. SE increased with the increasing fiber loading, fiber length and number of fiber layer, and VR had an opposite tendency. For the board with 5 mm thickness, the percolation threshold of fiber loading was between 0.008 and 0.02 % (weight of iron fiber/weight of Tetra paks). The boards had excellent total EMI shielding performance in range of 9000 Hz–200 MHz and 600–1500 MHz. This value-added product could be used in packaging, construction and other application fields and exhibited both environmental and economic advantages. It also could be considered as a step toward paper/plastic/aluminum composite waste management and preventing municipal solid wastes environmental pollution.

Synthesis and absorbing mechanism of two-layer microwave absorbers containing polycrystalline iron fibers and carbonyl iron

Polycrystalline iron fibers were fabricated by α-FeOOH fiber precursors. Two-layer microwave absorber had been prepared by as-prepared polycrystalline iron fibers and carbonyl iron. The structure, morphology and properties of the composites were characterized with X-ray diffraction, scanning electron microscope and Network Analyzer. The complex permittivity and reflection loss (dB) of the composites were measured employing vector network analyzer model PNA 3629D vector in the frequency range between 30 and 6000MHz. The thickness effect of the carbonyl iron layer on the microwave loss properties of the composites was investigated. A possible microwave-absorbing mechanism of polycrystalline iron fibers/carbonyl iron composite was proposed. The polycrystalline iron fibers/carbonyl iron composite can find applications in suppression of electromagnetic interference, and reduction of radar signature.

Microstructure and Properties of Absorbing Textile Iron Fiber

Application of absorbing material mostly concentrated in the range of hard materials, flexible absorbing fabric made of iron fiber has important research significance in order to meet the special military environment. Morphology, micro-elements element type and content of the iron fibers were tested. The absorbing properties and spinning performance of iron and fiber were discussed. The results show that cross-section of iron fiber made of copper production was jagged and multiple channels exist in longitudinal, which is benefit for spin ability. Its morphology and composition of the fiber have a catalytic effect in absorbing properties.

Improved Corrosion Resisting Property of Magnetism Iron Fiber by SiO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; Coating

To improve the oxidation resistance property of iron fibers, a SiO2 coated iron fiber was prepared by sol-gel method, and its microstructure, element and phase composition, antioxidation property, and crystallization were characterized by scanning electron microscopy, thermal gravimetric analysis, X-ray diffraction and 3% CuSO4 solution dripping. It was found that the surface of the iron fiber can be fully covered with SiO2 by using Sol-Gel method. Our results also indicated that the time of iron begin to be corrupted in 3% CuSO4 solution drip increased from 30 s to 240 s, and the temperature increased from 200?C to 310?C. In addition, the oxidation and antioxidation mechanisms of the SiO2 coated iron fiber have also been discussed in this work.