Various Types Of Fibers Research Articles

GAWBS Noise in Digital Coherent Transmission

This paper presents recent progress on guided acoustic wave Brillouin scattering (GAWBS) noise in single-core fiber (SCF), multi-core fiber (MCF), and few-mode fiber (FMF). First, we describe theoretical analyses of GAWBS phase noise generated in these various types of fiber. By using three types of SCF, namely ultra-large area fiber (ULAF), standard single-mode fiber (SSMF), and dispersion-shifted fiber (DSF), we show that the GAWBS phase noise depends strongly on the effective core area A <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub> . We also describe the GAWBS phase noise in four-core fiber (4CF), where it is shown that GAWBS noise in the off-center core is quite different from that in SCF. Furthermore, we describe the GAWBS phase noise in FMF supporting two LP modes. Then, we compare the GAWBS noise powers induced in SCF, MCF, and FMF. Next, we describe experiments on GAWBS phase noise in various fibers, which agree well with the theory. We also measured and analyzed the GAWBS phase noise correlation between the cores in a 4CF, where it is shown that the correlation between cores strongly depends on the core position. Finally, we describe the influence of GAWBS phase noise on digital coherent transmission. We formulate the GAWBS phase noise based on the Gaussian distribution and evaluate its influence on the BER characteristics in a coherent QAM transmission. We found that it is difficult to realize a transoceanic-class QAM transmission with a QAM multiplicity of higher than 64 even without other impairments. Furthermore, we evaluate the SNR penalty induced by the GAWBS noise in a long-haul transmission by taking account of the amplified spontaneous emission (ASE) and nonlinear interference noise, which are unavoidable in actual systems. The calculated results show that the influence of the GAWBS noise is smaller than the other impairments, but it cannot be neglected in system evaluations.

Effect of incorporating fibers in reactive powder concrete – A review

Modified form of High-Performance Concrete is a Reactive- Powder Concrete(RPC) which was first found by PierreRichard and Marcel Cheyrezy, they successfully built France laboratory using RPC. High compressive strength of over 200 MPa has been achieved, with flexural strength up to 40 MPa, and in certain cases crushing strengthup to 800 MPa with the introduction of hybrid fibre reinforcement. Cement OPC grade, silica fume, quartz sand, crushed quartz flour, water, a superplasticizer, and fibre reinforcement all contribute to making RPC.These materials have high durability characteristics as a result of their extremely low porosity, low permeability, limited shrinkage, and higher corrosion resistance. To increase package density, the powder combination of RPC should have a variety of granular particle classes. By dense packaging theory and grading optimization technique, the absence of coarse aggregate increased compactness. Because of its compactness, it reaches high strength. The rapid hydration of cement and silica fume at a high curing temperature of 100 °C as compete to 27 °C is something that causes the higher early strength. This paper discusses about the hybrid fibers incorporation in RPC under various curing conditions and its enhancement in strength than single fibers. Using micro and macro fibers dramatically improves the properties of RPC and thermal properties with various types of fiber. The mechanical characteristics of the RPC beam without the hybrid fiber, on the other end, are the lowest of all the mixtures. Apart from these characteristics, RPC can be utilized for industrial and nuclear waste storage facilities due to its ultra-dense microstructure, which provides ultra-high strength even at elevated temperature and water resistance. This paper infers that the addition of hybrid fiber in RPC considerably reduces the spalling of concrete at elevated temperatures and it exhibits superior strength and durability.

An Experimental Evaluation of Impact Strength of Fiber Reinfoced Concrete by using Drop Weight Test Method

Abstract: Using the Drop weight test method on slab panels with various types of fibre and their various proportions, this research examines the impact resistance of reinforced concrete's fibre resistance. The results of the IS drop weight test method, which measured the impact qualities of objects travelling at low and high speeds as well as the spilling and scabbing areas, are discussed in the current review study. The most frequently employed test. The results will be increases with the fibers added in percentages.

Tensile Failure Behaviors and Theories of Carbon/Glass Hybrid Interlayer and Intralayer Composites

Hybrid composites combine various types of fiber that not only provide an effective method to minimize material costs but also enhance the mechanical properties of composites. The tensile fracture behaviors of hybrid composites are more complex than single-fiber composites due to various reinforcing fibers and hybrid effects, and the relationship between tensile behaviors and hybrid structures is not clear. In this paper, various structures of C/G (carbon/glass) interlayer and intralayer hybrid composites were designed, and tensile behaviors were investigated; it revealed that tensile failure is characterized by the synergistic effect and failure acceleration effect. Second, the tensile properties of interlayer and intralayer hybrid composites with various hybrid ratios and stacking structures were systematically analyzed; our results demonstrated that the tensile strength of interlayer and intralayer hybrid composites was predominantly impacted by the hybrid ratio of C/G and increased with the increase in carbon fiber content. For interlayer hybrid composites, with the assistance of the synergistic effect, excellent tensile strength could be obtained for the glass fiber sandwiched carbon fiber structure. For intralayer hybrid composites, the tensile strength was small, while the dispersion degree was high. We compared the tensile properties with theoretically calculated values based on the rule of mixing (ROM) and revealed that the tensile modulus and strength of interlayer and intralayer hybrid composites exhibited a positive hybrid effect. This work serves as a foundation for the structural optimization and potential applications of C/G non-crimp hybrid composites.

Statistical Approach Model to Evaluate Permanent Deformation of Steel Fiber Modified Asphalt Mixtures

A good asphalt mixture is very important to maintain the triangle of sustainability. Many accidents occur due to pavement damage such as permanent deformation caused by the external loads induced by heavy traffic. Stone Mastic Asphalt (SMA) has a low resistance to moisture and other performances. Many researchers have conducted on SMA using various types of fiber. However, not much research has been done using steel fiber in the SMA mixture and has analyzed the result obtained using a statistical approach. The objective of this research was to identify the optimum amount of steel fiber in a modified asphalt mixture and characterize the performance of steel fiber in the SMA mixture using the statistical approach of Response Surface Methodology (RSM) in Design Expert Software. In this study, various steel fiber proportions of 0 percent, 0.3 percent, 0.5 percent, and 0.7 percent by the total weight of the SMA mixture were used. The Marshall stability and flow test, dynamic creep and moisture susceptibility test, and ultimately, RSM analysis were used to evaluate the properties and performance of the steel fiber-modified SMA, which contained 6.2 percent of PEN 60/70 asphalt binder content. The testing findings unmistakably demonstrated that the addition of steel fiber greatly improves the SMA mixture’s resistance to moisture and permanent deformation. An amount of 0.3 percent was found to be the most optimum steel fiber content from the optimization by using Response Surface Methodology, thus proven with additional steel fiber in the SMA mixture enhancing the performance of the mixture. As a result, it can be determined that the addition of steel fiber to SMA asphalt mixtures has improved the properties and performance in the construction of asphalt pavements, and the RSM method is an efficient statistical method for producing an appropriate empirical model for relating parameters and predicting the best performance of an asphaltic mixture.

Strength properties of fiber reinforced concrete including steel fibers

PurposeThis paper aims to study the influence of the presence of steel and polyolefin (PO) fibers on the mechanical and durability properties of fiber and hybrid fiber-reinforced concrete (FRC and HFRC).Design/methodology/approachHooked-end steel fibers having a length of 35 mm were applied at four different fiber content 1.0%, 1.5%, 2.0% and 2.5%, respectively. PO fibers having the length of 45 mm were also replaced with steel fibers at three different fiber content, 0.6%, 0.8% and 1.0%, to provide HFRC. The compressive, indirect tensile and flexural strengths; electrical resistivity; and water absorption were evaluated in this study.FindingsThe results showed that the addition of both steel and PO fibers led to improvements in the mechanical properties of FRC and HFRC. However, the replacement of steel fibers with PO fibers led to a slight loss in mechanical properties. Also, it was concluded that the addition of various types of fibers to concrete decreased both the electrical resistivity and water absorption compared with the control sample. Finally, distance-based approach analysis was used to select the most optimal mix designs.Originality/valueAccording to this method, the HFRC specimen including 1.2% of steel and 0.8% of PO fibers was the most optimal mix design among all fiber-reinforced mix designs.

Experimental studies on confined compressive strength of Stainless Steel Wire Mesh (SSWM) wrapped concrete columns

The findings of an experimental evaluation of the axial compressive strength of an M25 grade Plain Cement Concrete (PCC) column confined with locally available Stainless Steel Wire Mesh (SSWM) are presented in this paper. Various types of Fiber Reinforced Polymer (FRP) are usually employed to strengthen the load-bearing components of concrete structures. However, these FRP materials exhibits brittle failure and debonding of FRP strip or wrap. Stainless Steel Wire Mesh (SSWM), on the other hand, is a cost-effective substitute for FRP materials when it comes to strengthening of structural elements. In this study, effectiveness of SSWM for confinement of concrete columns is demonstrated through experimental study. For the research, column specimens with a diameter of 150 mm and a height of 300 mm are used. Test specimens are strengthened with one-layer circumferential wrap of SSWM. Three variants of SSWM i.e. SSWM 30 × 32, SSWM 40 × 32 and SSWM 50 × 34 are considered for the study. After 28 days of moist curing, SSWM is applied to the column surface using epoxy SIKADUR 30LP. Axial compressive load-carrying capacities of strengthened specimen are compared with that of control specimens. From the comparative study it is found that SSWM 40 × 32 performs better compared to other variants of SSWM considered for this study. Compared to the control specimen, the load-carrying capacity of the column strengthened with SSWM 40 × 32 is increased by 29.35%. For all the specimen, failure patterns are observed in addition to the load–displacement and stress–strain behaviour. Results of present experimental investigation establishes the suitability of SSWM for confinement or strengthening of concrete elements subjected to compression.

Design and Fabrication of an Instrument for Splitted Jute Fiber Length Measurement

Fibers are the main raw materials in the textile industry. Now-a-days various types of fibers are available around the world, but all fibers are not textile fibers. Because for being textile fibers, the fibers must have some particular physical and chemical properties. The length of natural fiber plays an important role both in the spinning process and product quality. In this work, it is highlighted about a long staple natural fiber which is called jute fiber. In the 19th century, jute fiber was called the *Golden Fiber* of Bangladesh. After that this fiber lost its name and fame for the cause of our negligence and lack of knowledge. It is very difficult to know about jute because a few people were working on it. Though it’s a long fiber but there are some problems with its fixed length because this fiber consists of a large number of ultimate cells whose length is 1.5 to 4 millimeters, and these cells are attached by lignin which is known as natural cement. A long fiber which is 5 to 10 feet forms after attaching these ultimate cells. During the retting period some of the lignin layers break down and long fiber length of fibers becomes shorter. Another important thing is these fibers have a mesh structure for this reason it’s difficult to identify the actual length of the fibers. That’s why fibers obtained after retting are passed through jute carding machines. The main function of the jute carding machine is to split up and break down the mesh structure. After carding, it’s quite easy to measure the length of splitted jute fibers. There are not any suit-able machines for measuring the length of jute fibers. Previously people use the scale for measuring the jute fibers' length manually, through this it is so difficult to measure the length of the long fibers accurately. Here an instrument has been designed with Arduino UNO, Ultrasonic distance sensor, Image-j software, C-programming and fabricated for measuring the fibers' length easily and accurately as well as this instrument can measure the number of fibers in that particular length. By using this instrument anyone can easily measure the length of the fibers and the number of fibers within a short possible time efficiently.

Design and fabrication of an instrument for splitted jute fiber length measurement

Fibers are the main raw materials in the textile industry. Now-a-days various types of fibers are available around the world but all fibers are not textile fibers. Because for being textile fibers, the fibers must have some particular physical and chemical properties. The length of natu-ral fiber plays an important role both in the spinning process and product quality. In this work, it is highlighted about a long staple natural fiber which is called jute fiber. In the 19th century, jute fiber was called the *Golden Fiber* of Bangladesh. After that this fiber lost its name and fame for the cause of our negligence and lack of knowledge. It is very difficult to know about jute because a few people were working on it. Though it’s a long fiber but there are some problems with its fixed length because this fiber consists of a large number of ultimate cells whose length is 1.5 to 4 millimeters and these cells are attached by lignin which is known as natural cement. A long fiber which is 5 to 10 feet forms after attaching these ultimate cells. During the retting period some of the lignin layers break down and long fiber length of fibers becomes shorter. Another important thing is these fibers have a mesh structure for this reason it’s difficult to identify the actual length of the fibers. That’s why fibers obtained after retting are passed through jute carding machines. The main function of the jute carding machine is to split up and break down the mesh structure. After carding, it’s quite easy to measure the length of splited jute fibers. There are not any suit-able machines for measuring the length of jute fibers. Previously people use the scale for measuring the jute fibers' length manually, through this it is so difficult to measure the length of the long fibers accurately. Here an instrument has been designed with Arduino UNO, Ultrason-ic distance sensor, Image-j software, C-programming and fabricated for measuring the fibers' length easily and accurately as well as this instrument can measure the number of fibers in that particular length. By using this instrument anyone can easily measure the length of the fibers and the number of fibers within a short possible time efficiently.

A Review on Failure Modes and Cracking Behaviors of Polypropylene Fibers Reinforced Concrete

Despite being strong under compression, concrete is rather weak when subjected to tensile stress. Concrete has been reinforced with a variety of materials over time in order to resist tensile stresses. Among various types of fibers, polypropylene fiber, which is available in a range of sizes, is being used to strengthen concrete. The fiber also increases the concrete’s toughness, durability, and low permeability. Polypropylene fibers may be utilized in place of conventional reinforcement, according to a number of researchers. The aim of this study is to collect information from already carried out research on polypropylene fibers. Important characteristics of concrete, such as workability, compressive, tensile, and flexural strength, are reviewed. The review also explores cracking behavior and failure modes of polypropylene fiber reinforced concrete. Furthermore, durability aspects, such as water absorption, porosity, dry shrinkage, and microstructure study (scan electronic microscopy), were also reviewed. Results indicate that polypropylene fiber improved the mechanical strength and durability of concrete (particularly tensile capacity) but decreased the flowability of concrete. The optimum dose is important, as a higher dose adversely affects strength and durability due to a lack of flowability. Scanning electronic microscopy results indicate that the polypropylene fibers restrict the propagation of cracks, which improves the strength and durability of concrete. The review also indicates that shrinkage cracks are considerably reduced with the addition of polypropylene fibers. Finally, the review also provides future research guidelines for upcoming generations to further improve the performance of polypropylene fibers that reinforce concrete.

Influence of Using Different Types of Fibers on The Mechanical Properties of Roller Compacted Concrete A Review

There is an important and urgent need to construct more durable pavements, Roller Compacted Concrete (RCC) is a strong and durable product that is commonly used to construct pavements because of its various benefits, including quick paving, labor savings, a decrease in quantity of Portland cement contains, and the use of cementitious substances in place of cement. Also, RCC has disadvantages which are its rigidity, cracking due to thermal or plastic shrinkage, flexural strength, fatigue loading, and lower tensile strength. So, using different types of fiber in the construction of RCC is necessary to control these disadvantages. This paper reviews the consequences of the various types of fibers used by researchers and which types are more advantageous, have a good option to be used, and be a guide to clarify the significance of the fibers in the construction of RCC pavements. Most of them have higher durability and cost-effectiveness while some of them have environmental issues

Influence of Stone Processing Waste on Mechanical, Durability, and Ecological Performance of Hybrid Fiber-Reinforced Engineered Cementitious Composite

The current study is focused on the characteristics of sustainable engineered cementitious composites (ECCs) with the inclusion of various types of fibers (PVA, PET, and MSE) in hybridization, silica sand (SS), river sand (RS), and stone processing waste (SPW). SPW is termed as hazardous material because of the presence of finer particles and inorganic substances which contribute to leaching problems, and cause adverse effects on aquatic life and human health. The objective of this study was to introduce new kind of cost-effective, sustainable, and greener ECC to encourage its use in diversified applications. The characteristics of different ECC mixtures were assessed by observing the slump flow, compressive, tensile, flexural, ultrasonic pulse velocity, air permeability, electrical resistivity (ER), sorptivity, ecological behavior, and cost analysis. Experimental results revealed that the combination of micro-fibers enhanced the overall performance of ECC with reduction in the matrix cost. The addition of SPW in place of aggregates enhanced the flowability, strength, and durability characteristics, and contributed to reducing the carbon dioxide emissions. This study confirms that the combined use of PVA, PET, and MSE fibers with SPW inclusion is a promising alternative over the fully PVA blended ECC with SS.

3D-Printed Fiber-Reinforced Polymer Composites by Fused Deposition Modelling (FDM): Fiber Length and Fiber Implementation Techniques.

Fused Deposition Modelling (FDM) is an actively growing additive manufacturing (AM) technology due to its ability to produce complex shapes in a short time. AM, also known as 3-dimensional printing (3DP), creates the desired shape by adding material, preferably by layering contoured layers on top of each other. The need for low cost, design flexibility and automated manufacturing processes in industry has triggered the development of FDM. However, the mechanical properties of FDM printed parts are still weaker compared to conventionally manufactured products. Numerous studies and research have already been carried out to improve the mechanical properties of FDM printed parts. Reinforce polymer matrix with fiber is one of the possible solutions. Furthermore, reinforcement can enhance the thermal and electrical properties of FDM printed parts. Various types of fibers and manufacturing methods can be adopted to reinforce the polymer matrix for different desired outcomes. This review emphasizes the fiber types and fiber insertion techniques of FDM 3D printed fiber reinforcement polymer composites. A brief overview of fused deposition modelling, polymer sintering and voids formation during FDM printing is provided, followed by the basis of fiber reinforced polymer composites, type of fibers (synthetic fibers vs. natural fibers, continuous vs. discontinuous fiber) and the composites' performance. In addition, three different manufacturing methods of fiber reinforced thermoplastics based on the timing and location of embedding the fibers, namely 'embedding before the printing process (M1)', 'embedding in the nozzle (M2)', and 'embedding on the component (M3)', are also briefly reviewed. The performance of the composites produced by three different methods were then discussed.

Destructive and Nondestructive Tests for Concrete Containing a Various Types of Fibers

Fibers have been considered an effective material that was used to improve the concrete's weak properties, namely its tensile strength, ductility, and crack resistance. Thus, the current study highlights two major objective, the former is the fibers shapes and types on the mechanical properties of the fresh and hardened concrete while the latter explores the impact of the fiber contents on the concrete mechanical properties developments. To achieve these targets six types of fibers (five of them made of steel and the last was polyolefin fibers) with various shapes are utilized. The tests were carried out to investigate the fibers shape and material contribution in the concrete mix properties improvement. The samples were subjected to destructive and non-destructive tests such as workability, compression, bending, and splitting. The non-destructive tests include ultrasonic pulse velocities and the Schmidt Hammer test. Three kinds of fibers (two of steel and one of polyolefin fiber) are used with variable content ratios of 0.5, 0.75, 1.0, and 1.5% to study the fiber content effect. Generally, the workability of fresh concrete has a reverse relationship with fiber presence and fiber content ratios. The compressive capacity, splitting and flexural strength has a direct proportion with fibers contents. The hooked steel fibers appeared the best results in terms of shape comparison. Doi: 10.28991/CEJ-2022-08-11-07 Full Text: PDF

Utilization of carbon nanotubes and steel fibers to improve the mechanical properties of concrete pavement

BackgroundRigid pavements have become an urgent demand in recent years, as these pavements need less maintenance and renovation than other types. However, traditional rigid pavement faces various challenges and difficulties over its lifetime. It has a much higher initial erection cost than asphalt pavements, a greater sensitivity to dynamic stresses, and a highly susceptible to temperature variations causing cracking. Previous works dealt with these drawbacks by using effective materials as alternatives to cement and/or aggregates in pavements mixtures. In the last few years, much interest has been carried out in nanomaterial applications to improve the mechanical performance of construction materials, which can also be used for rigid pavement constructions. This improvement is due to nanomaterials' role in concrete as nanoreinforcements and nanofillers. On the other hand, various types of fibers have been used to improve the performance of concrete constructions. This study investigates the effect of adding carbon nanotubes (CNTs) and steel fibers (SFs) to concrete mixtures. A series of experiments on concrete mixes with various weight percentages of CNTs (0%, 0.025%, 0.050%, and 0.075%) were added to the mixtures to determine the best cost and amount of CNTs to add to a concrete mix. Compressive, tensile, and flexure strength characteristics are investigated. In the second experimental stage of this work, the effect of adding steel fibers to the mixture was investigated.ResultsAccording to the results, the optimal carbon nanotube content in concrete is 0.05%. Compared to other concrete combinations with varying proportions of CNTs, this quantity offers the maximum compressive, tensile, and flexural strength. Additionally, SFs can improve the mechanical properties of the mix as well as enhance its post-cracking and fatigue behavior. Adding both CNTs with SFs increased compressive, tensile, and flexural strength by 22.7%, 29.3%, and 70.8%, respectively, more than the traditional pavement.ConclusionThis work found that combining SFs with CNTs improves the mechanical properties of the concrete mortar, resulting in a stronger mortar that can withstand more loads than the traditional one.

Analysis for the efficiency of additional dispersed reinforcement using coconut fiber for a concrete beam with traditional steel bar reinforcement

Concrete is widely used as a building material throughout the world. However, its use in building structures is limited due to its low tensile strength. This problem can be partially solved using steel bars reinforcement, as well as using dispersed reinforcement with various types of fibers. The authors propose the simultaneous traditional reinforcement of a concrete structure with steel bars with additional dispersed reinforcement with natural coconut fibers, relatively cheap and widely available in many countries in Africa, Asia and Latin America. The purpose of this study is to analyze the effectiveness of the proposed solution by comparing the required amount of steel reinforcement (by weight) for a beam made of traditional concrete and a similar beam with additional dispersed reinforcement with coconut fibers. Deflections and cracking in beams were investigated. The analysis was carried out using Autodesk Robot Structural Analysis Professional 2022 software. The results showed that a beam additionally reinforced with coconut fiber requires 11% less steel reinforcement (by weight) compared to a similar beam made of traditional reinforced concrete. In addition, the coconut fiber reinforced beam experienced 6% less deflection and significantly less stress cracking compared to a simple concrete beam. These results proved that the approach proposed in the work noticeably improves the performance of reinforced concrete in the structure, and also makes it possible to obtain significant savings in reinforcing steel.

Effect of stacking sequence on tensile properties of glass, hemp and kenaf hybrid composites

Abstract Natural fibre reinforced polymer composites have the potential to be utilized at various applications due to their non-hazardous effect to the environment, biodegradable properties as well as enhanced mechanical characteristics. Nevertheless, mechanical properties of these composites are complicated to understand and predicted due to complex interaction between matrix and different type of fibres, fibres architecture and fibres arrangement. Therefore, this paper aims to study the effect of various types of fibres; kenaf mat, hemp mat and Glass Chopped Strand Mat as a core, core thickness; 1, 2 and 4 layers, and fibre arrangements; kenaf mat, hemp mat and Glass Chopped Strand Mat arranged in middle layer (core) or outer layer (skin) on tensile properties of hybrid composites. The hybrid composite specimens were prepared through combinations of hand lay-up and vacuum methods in which both methods are commonly employed techniques in industry. There are four types of fibre arrangement systems involved: (2:1:2), (2:2:2), (2:4:2) and (1:4:1). As expected, the glass fibres hybrid composites had the highest tensile performance compared to other hybrid composites. The fibre arrangement (2-1-2) was the best option for all types of fibres, while the use of 4 layers of kenaf mat, hemp mat and Glass Chopped Strand Mat as core material reduced the tensile properties. In comparison of (2-2-2) and (1-4-1), kenaf mat and Glass Chopped Strand Mat performed better as a core, while hemp mat performed better as skin.

Properties of dispersed fibers for efficient concrete reinforcement

The question of increasing the reliability and durability of reinforced concrete structures is a priority. One of the ways to increase the strength of concrete is using of dispersed reinforcement. The interest of using of fiber-reinforced concrete in Russia, as well as in Europe, Asia and the USA has increased significantly in recent ten years. The improvement of the physical and mechanical properties of concrete is noted to depend on the reinforcement parameters, such as the volume content of the fiber, the characteristics of the dispersed reinforcement, the structure of the concrete matrix, etc. Authors consider various types of fibers for dispersed concrete reinforcement, specifically polypropylene, polyethylene, nylon, acrylic, polyester, cotton, asbestos, glass, basalt, steel, carbon. Description of the main advantages and disadvantages of each type of fiber is given. Comparative characteristics are presented in terms of density, tensile strength, modulus of elasticity, elongation at fracture of the materials used to manufacture the fiber. The influence of fibers on crack strength of fiber-reinforced concrete under impact loads is studied. Analytical review of existing works found that it is possible to achieve a significant increase of strength of fiber-reinforced concrete in axial compression, tension, tension in bending, shear compared to ordinary heavy concrete.

Investigating the Hybrid Effect of Micro-steel Fibres and Polypropylene Fibre-Reinforced Magnesium Phosphate Cement Mortar

To overcome the drawbacks caused by the intrinsic brittleness of cementitious materials, various types of fibres were incorporated as reinforcements. Extensive research on Ordinary Portland cement indicated that compared with the use of a single type of fibres, the mixed-use of multiple fibres can significantly improve both strength and toughness of the cementitious composites, which is referred to as the hybrid effect. However, such hybrid effect in multiple fibre-reinforced magnesium phosphate cement-based composite (HFRMC) still lack quantitative understanding. Therefore, this study conducted a series of experiments, including slump flow tests, compression tests, four-point bending tests and microstructure analysis, to investigate the hybrid effect of micro-steel fibres (MSF) and polypropylene (PP) fibres in HFRMC. Two types of mixed designs of HFRMC were conducted: 1. total fibres fraction (including both PP fibres and MSF) was fixed to be 1.6%; 2. PP fibres fraction was fixed to be 1.6% with different addition of MSF. Our results indicated that the slump flow of magnesium phosphate cement mortar varied around 7.6–8.8% with the hybrid use of MSF and PP fibres, while the flexural strength and toughness increased around 13.7–23.1% and 1.6–45.9%, respectively.

Controlled-Alignment Patterns of Dipeptide Micro- and Nanofibers.

Ordered assemblies of the peptide diphenylalanine (FF) are produced and deposited on planar substrates. The FF aggregate growth is achieved through precipitation from aqueous ammonia solutions induced by solvent evaporation. The applied dip-coating technique confines the FF assembly growth to a narrow zone near the three-phase contact. The growth was observed online by optical microscopy and was investigated systematically as a function of the process parameters. Depending on the external gas flow (to influence solvent evaporation), the withdrawal speed, the initial FF, and the initial ammonia concentrations, FF forms long, straight, and rigid microfibers and/or shorter, curved nanofibers. Under certain process conditions, the FF fibers can also aggregate into stripes. These can be deposited as large arrays of uniform stripes with regular widths and spacings. Scenarios leading to the various types of fibers and the stripe formation are presented and discussed in view of the experimental findings.