Effect Of Fiber Hybridization Research Articles

Evaluation of Axial Compressive and Tensile Properties of PE/PVA Hybrid Fiber Reinforced Strain-Hardening Geopolymer Composites.

The strain-hardening geopolymer composite (SHGC) is a new type of fiber concrete with excellent ductility and environmental friendliness. However, the high cost of fibers greatly limits its widespread application. This paper proposes the use of untreated low-cost polyvinyl alcohol (PVA) fibers and polyethylene (PE) fibers to develop a low-cost, high-performance SHGC. Axial compression and axial tension tests were conducted on the SHGC with different PE fiber volume fractions (1%, 1.5%, and 2%) and different PVA fiber replacement ratios (0%, 25%, 50%, 75%, and 100%) to investigate the hybrid effects of fibers with different surface properties and to reveal the mechanism of fiber hybridization on the mechanical behavior of SHGCs. The results show that increasing the PE fiber volume fraction improves the compressive and tensile ductility of the SHGC while increasing the PVA fiber replacement rate impacts the strength indicators positively due to the good interface effect formed between its hydrophilic surface and the matrix. When the PVA fiber replacement ratio is 100%, the compressive strength (93.4 MPa) of the SHGC is the highest, with a 21.1% increase compared to the control group. However, the tensile strength shows a trend of first increasing and then decreasing with the increase in the PVA fiber replacement ratio, reaching the highest at a 25% replacement ratio, with a 12.5% increase compared to the control group. Furthermore, a comprehensive analysis of the economic and environmental performance of the SHGC indicates that a 25% PVA fiber replacement ratio results in the best overall economic benefits and relatively low actual costs, although the effect of fiber hybridization on carbon emission indicators is not significant. This paper provides new ideas and a theoretical basis for designing low-cost SHGCs.

Viscoelastic Performance of Bagasse/Glass Fiber Hybrid Epoxy Composites: Effects of Fiber Hybridization on Storage Modulus, Loss Modulus, and Damping Behavior

Abstract This study aimed to investigate the viscoelastic properties of bagasse/glass fiber multilayered hybrid reinforced epoxy composites, focusing on how fiber hybridization affects dynamic mechanical performance. Epoxy composites with various layering sequences, including all-glass (AG), all-bagasse (AB), bagasse-glass-bagasse (BGB), and glass-bagasse-glass (GBG), were fabricated and analyzed using dynamic mechanical analysis (DMA) to measure storage modulus (E'), loss modulus (E''), and damping factor (tan δ). The results showed that hybrid composites (GBG and BGB) experienced a decrease in storage modulus by approximately 25% compared to AG, indicating enhanced polymer molecular chain mobility and improved interfacial adhesion between bagasse fibers and the epoxy matrix. The glass transition temperature (Tg) was slightly lower in hybrid composites, with GBG at 61 °C and BGB at 60 °C, compared to 62 °C for AG. In terms of energy dissipation, AG exhibited the highest loss modulus peak at 62 °C, while AB showed the lowest with a Tg at 53 °C. The damping factor analysis revealed that AB had the highest damping peak (tan δ = 0.9) at 61 °C, although this occurred at a lower temperature than the AG composite (tan δ = 0.7 at 76 °C). These findings suggest that bagasse and glass fiber hybrid composites offer tailored viscoelastic properties, making them suitable for applications in automotive components, aerospace structures, and sports equipment.

Effect of hybridization on the mechanical performance and cost efficiency of carbon/flax bio‐hybrid composites

AbstractThis research investigates the effects of fiber hybridization on the mechanical performance of carbon/flax bio‐hybrid laminates. The study comprised of manufacturing and analyzing five distinct composite laminates, comprising pure carbon and various carbon/flax configurations with symmetric and asymmetric layups. The laminates were subjected to uniaxial tensile and low‐velocity impact testing at energy levels from 30 to 75 J. Quantitative and qualitative analyses were conducted to assess the damage/failure patterns to determine the changes due to hybridization and stacking sequence. The experimental results revealed that integrating flax layers into different bio‐hybrid configurations significantly influences their strength, stiffness and impact resistance. One of symmetric layups, having uniform distribution of flax layers throughout thickness, demonstrated the most enhanced performance. To facilitate comprehensive comparison, two indices were developed: Composite‐Performance Index (CPI) and Cost‐Effectiveness Index (CEI). These indices indicate that bio‐hybrid configurations, optimally designed with appropriate number of evenly distributed flax layers, can match or surpass performance of pure carbon layup. The study concludes that incorporating flax into carbon fiber laminates can yield substantial benefits in impact performance with slight compromise in tensile strength and stiffness. However, the overall cost efficiency of bio‐hybrid composites is superior, considering both tensile strength and impact performance.Highlights Effect of fiber hybridization on the mechanical performance of hybrid laminates was studied. Carbon/Flax composites exhibited slightly lower tensile strength compared to carbon‐based layup. Symmetric layups with evenly distributed flax layers showed enhanced impact performance. Cost efficiency of bio‐hybrid composites is superior for both tensile and impact performance.

Effect of fiber hybridization on the electromagnetic shielding of UHPFRCC panel

Interest in electromagnetic shielding of cement-based materials is increasing to protect human health and electronic equipment from electromagnetic interference (EMI). EMI shielding effectiveness of cement-based materials can be reduced by cracking, and thus cracking behavior is a major factor influencing EMI shielding effectiveness reduction of cracked cementitious composites. In this study, the effects of hybridization of fibers on the cracking behavior and EMI shielding effectiveness of non-cracked and cracked ultra-high-performance fiber-reinforced cementitious composite (UHPFRCC) were investigated. UHPFRCC containing 1.5 vol% long steel fibers was considered as a control variable, and substitution with 0.5 vol% short steel fibers, PE fibers, and carbon fibers was considered as experimental variables. Compressive strength, density, direct tensile behavior, electrical conductivity, and capacitance tests were conducted. After that, crack length, width, area, and EMI shielding effectiveness of panels that were cracked by step-by-step loading were measured. According to the test results, the effect of short steel fiber substitution was insignificant. PE fibers significantly improved tensile strain performance, but it decreased EMI shielding effectiveness when the thickness of the panel decreased. On the other hand, carbon fiber substitution decreased mechanical performance and electrical conductivity due to dispersion problems, but it improved EMI shielding effectiveness at 1 GHz by 30.0–62.9% by dielectric polarization. The total crack length at each displacement level increased logarithmically with the increase in normalized toughness, and carbon fiber substitution showed the lowest crack dispersion capacity. However, carbon fiber substitution has been shown to alleviate the degree of deterioration of EMI shielding effectiveness after cracking.

Synergistic effects of fiber hybridization on the mechanical performance of seawater sea-sand concrete

This study investigated the effect of hybrid fibers and their synergic interactions on the mechanical properties of seawater sea-sand (SWSS) concrete. These properties include compressive strength, elastic modulus, splitting tensile strength, compressive stress-strain behavior, and ductility, as well as slump and air content. Two hybridizations were incorporated: hybrid micro-fibers (hybridization of the type of fibers) and hybrid micro- and macro-fibers (hybridization of the length of fibers). The hybrid fibers comprised three micro-fibers—polypropylene (PPS), polyvinyl alcohol (PVA), basalt (BF)—and two macro-fibers—polypropylene (PPL), and twisted polypropylene (TPPL)—with a total volume fraction of 0.25%. The findings revealed that if designed properly hybrid micro-fibers can outperform mono-fibers in mechanical properties and ductility, bridging micro-cracks. This study revealed that incorporating PVA/PPS and BF/PPS hybrid micro-fibers enhanced both interlocking, facilitated by the chemical bonding of PVA and BF, and elongation, enabled by PPS. This synergistic effect led to a significant 33–35% increase in compressive elastic modulus compared to mono PPS fibers. At the same total dosage of fibers, PVA/BF hybridization significantly improved SWSS concrete total energy absorption and residual strength under compression by 44% and 181% over mono BF incorporation. Increasing BF in hybrid fibers significantly reduced ductility and increased brittleness. In PVA/PPL hybridization, PVA fiber improved PPL bonding strength and tensile capacity through chemical bonding with concrete, enhancing ductility and residual strength under compression by 59% and 65% over mono PPL fiber. Overall, hybrid fibers improved the mechanical properties and ductility of SWSS over mono-fibers. This was due to positive synergy and inter-fiber performance due to mechanical and chemical bonding, overcoming individual fiber type limitations (e.g., poor bonding, tensile strength, or ductility). This effect was more pronounced with micro- and macro-fiber hybridization. The findings of this study can be used to provide an improved performance for SWSS concrete by adding hybrid fibers to the mix considering the synergic interactions of fibers.

Effect of fibre hybridization and stacking sequence on the low velocity impact response of flax/basalt/aluminum composite-metal joints

A lot of composite materials with better impact resistance and better strength and stiffness can be manufactured these days. Many researchers have been using different materials to form new composites to understand their impact performance. This paper discusses such an attempt to make new composites by utilizing the concept of hybridization and then proposes which among them has better strength and performance under low-velocity impact (LVI) loading. In this work, circular patches of composites made up of a combination of basalt and flax fibers were used while being bonded with aluminum plate Al 2024-T3 of 3 mm thickness. The three different configurations which include asymmetric, symmetric, and sandwich were prepared using vacuum assisted bagging process and their impact performances were investigated using the Drop Weight Impact test. The results obtained were analyzed and they concluded that the asymmetric configuration of basalt/flax composite has better impact resistance, and strength and is better to use in structural components of automobiles, and the defense industry as compared to the other two.

Investigating Stacking Configuration and Fiber Hybridization Effects on Low-Velocity Impact Behavior in Twill Woven Carbon/Flax Composites

In this study, experimental research has been done to investigate and analyze the effects of fiber hybridization and stacking configurations on the impact performance of carbon/flax bio-hybrid composite laminates. A total of four composite laminates with pure carbon, sandwich, symmetric, and asymmetric stacking configurations were manufactured and investigated in terms of low-velocity impact test with varying energies between 30J and 75J. Both qualitative and quantitative analysis were performed to analyze the damage and failure patterns in the composite layups and were compared with the pure carbon-based layup to identify the effects stacking configuration. The experimental findings showed the symmetric layup having a consistent distribution of flax fiber layers, showed the most enhanced performance as compared to the carbon-based layup Moreover, damage and failure modes differed among layups and increased with varying impact energies. Furthermore, to enable the thorough comparison of the configurations, Composite Performance Index (CPI) was developed, which suggests that bio-hybrid configurations when designed optimally with a suitable number of evenly distributed flax layers, can equal or exceed the performance of a pure carbon fiber configuration.

Low velocity impact performance of natural fibre reinforced polymer composites: a review

Natural fibre-reinforced polymer composites (NFRPC) are versatile and applicable materials for structural applications that require durability and reliability under various forces. However, these composites are susceptible to crack formation when exposed to low-velocity impact (LVI) loads, compromising their functionality and performance. Therefore, it is essential to investigate the influence of LVI on NFRPC and their characterization methods, testing standards, and failure mechanisms. This paper reviews the latest research and development on the characterization, testing, and modelling of NFRPCs under LVI loads. It also explores the impact behaviour of various natural fibres, such as kenaf, bamboo, mallow, buriti, and curaua, and the effect of fibre hybridization and nanofiller incorporation on the LVI response of NFRPCs. The paper evaluates the properties, failure mechanisms, and applications of NFRPCs in relation to LVI resistance. The paper provides useful information for developing advanced composite systems and achieving material efficiency for various structural applications. Finally, it highlights the potential applications and challenges of NFRPC as LVI-resistant materials for advanced composite systems.

Post‐curing and fiber hybridization effects on mode‐II interlaminar fracture toughness of glass/carbon/epoxy composites

AbstractFailure by delamination is one of the primary concerns in laminated composites. The development and progression of the delamination results in the degradation of composite stiffness affecting its structural integrity and may ultimately result in composite structure failure. Therefore, knowledge of the evolution of delamination resistance and the factors which affect the delamination in composites is of utmost importance for the selection of materials. This study investigates the effect of fiber hybridization and post‐curing on mode‐II interlaminar fracture toughness (GIIC) of Glass/Carbon/Epoxy (GCE) composites. Carbon/Epoxy (CE), Glass/Epoxy (GE), and GCE composite laminates were molded employing the process of hand layup technique and post‐cured at different temperatures. GE laminates exhibited a superior load for delamination and deformation compared to CE and GCE laminates. The hybrid GCE laminates exhibited higher interlaminar fracture toughness compared to non‐hybrid GE and CE laminates, which can be attributed to the synergetic effect of Carbon and Glass fibers. The laminates post‐cured at 180°C exhibited higher fracture toughness in their corresponding groups. The delaminated surfaces of CE, GE, and GCE laminates were further examined under Scanning electron microscopy (SEM) to understand the effect of post‐curing and fiber hybridization on mode‐II interlaminar fracture toughness.

Combined effect of fiber hybridization and matrix modification on mechanical properties of polymer composites

Glass/carbon fiber reinforced hybrid composites are great candidates for wind turbine blade manufacturers to make larger blades. Variation of stacking sequences ensures design freedom to the composite engineers to optimize the composite structure's mechanical performance. On the other hand, matrix modification of polymer composites with nanoparticles is also of interest to introduce multifunctional properties. This research aims to scrutinize the influence of simultaneous fiber hybridization and matrix modification on polymer composites’ tensile, flexural, and low-velocity impact properties. Hybrid glass/carbon epoxy composites and hybrid glass/carbon/multi-walled carbon nanotube (MWCNT) multiscale polymer composites of stacking sequences [GCGCGC]S, [CGCGCG]S, and [G6C6] were manufactured. Fiber hybridization dramatically improved tensile strength between 51% and 76% compared to glass fiber composite. Depending on the stacking sequence, the flexural strength of the hybrid composites was improved between 10% and 16% concerning carbon fiber composite. With the introduction of MWCNTs, a slight increase in the tensile strength for unsymmetrical hybrid composites by around 5% and decreases by 7% for symmetrical ones were observed. Similar behavior was seen for bending characteristics. Additionally, low-velocity impact tests showed that it is achievable to bring greater impact peak forces up to 70% for hybrid composites than carbon fiber epoxy composites. MWCNTs modification of the matrix restrained the impact damage propagation, as proved by C-scan analysis.

Effect of fiber hybridization on tensile fracture of 3D woven textile composites

3D Woven composites provide the ability to handle higher damage tolerance (Pankow et al., 2019). Hybridization of fibers is an additional method to provide improved damage tolerance (Pankow et al., 2014) . This work is the first time that the tensile response of “hybrid” 3D woven composites (H3DWC) is investigated. The hybridization showed an increase in modulus with increasing carbon fiber volume fraction ( > 30 % in general). While, the strength showed a decrease that was proportional to the carbon fiber volume fraction ( > 78% of the baseline glass). Although the carbon failed, the material remains intact as the glass fibers have not failed, maintaining 80% of the strength after failure in the warp direction. The unsymmetric samples, which have benefits for bending type loading, produced coupled behavior due to thermally induced shrinkage. Overall looking at the combination of factors from previous bending work with this new tensile work, it can clearly be seen that there is a clear tradeoff in the amount and way one would perform hybridization.

Effect of fiber hybridization on mechanical properties of concrete

Ten concrete mixtures, using long and medium length hooked-end and short wave-shaped steel fibers, were designed to experimentally investigate the effect of hybrid reinforcement on workability, drying shrinkage, and mechanical properties of hybrid steel fiber reinforced concrete. The steel fibers reduced the workability and drying shrinkage. Hybrid fibers, including long hooked-end steel fiber, can produce a synergistic effect on compressive strength. For the adopted materials, a linear relationship was observed between shrinkage strain and compressive strength. The tensile splitting strength increased with the volume fraction of the hybrid fibers. The hybrid steel fibers generated a synergistic effect on the tensile splitting strength, with an almost constant ratio of tension splitting strength to compressive strength of hooked-end steel fiber reinforced concrete. The use of long hooked-end steel fiber reinforcement led to a higher modulus of rupture, residual strength, and toughness than other mono fibers. Flexural strength increased with the increasing volume fraction of hybrid fibers. Residual strength of hybrid steel fiber reinforced concrete varied with fiber hybridization. Overall, a concrete reinforced with a hybrid mix of all the considered steel fibers had the best performance among the considered ones.

Ultra-high-strength engineered/strain-hardening cementitious composites (ECC/SHCC): Material design and effect of fiber hybridization

It is well known that an increase in the compressive strength of cementitious composites is usually accompanied by a loss of tensile ductility. Designing and developing ultra-high-strength cementitious composites (e.g., ≥200 MPa) with high tensile strain capacity (e.g., ≥3%) and excellent crack resistance (e.g., crack width ≤100 μm) remain challenging. In this study, a series of ultra-high-strength Engineered Cementitious Composites (UHS-ECC) with a compressive strength over 210 MPa, a tensile strain capacity of 3–6% (i.e., 300–600 times that of ordinary concrete), and a fine crack width of 67–81 μm (at the ultimate tensile strain) were achieved. Hybrid design of fiber reinforcement and matrix for UHS-ECC was adopted by combining the ECC and ultra-high-performance concrete (UHPC) design concepts, and the effect of fiber hybridization and aspect ratio on the mechanical behavior of UHS-ECC was comprehensively investigated. The overall performance of UHS-ECC was assessed and compared with the existing high-strength ECC and strain-hardening UHPC, and it was found that the currently designed UHS-ECC recorded the best overall performance among the existing materials. Finally, the multiple cracking behavior of UHS-ECC was analyzed and modeled based on a probabilistic approach to evaluate its critical tensile strain for durability control in practical applications. The results of this study have pushed the performance envelope of both ECC and UHPC materials and provided a basis for developing cementitious composites with simultaneously ultra-high compressive strength, ultra-high tensile ductility, and excellent crack resistance.

Effect of Fibre Hybridization on Mechanical Properties of Nylon-Broom Grass/Root-Broom Grass Fibre Reinforced Hybrid Polypropylene Composites

In the present research, nylon-broom grass and onion root-broom grass reinforced hybrid polypropylene composites were manufactured using a hot press machine. Three different levels of fibre loading (5, 10, and 15 wt.%) with fibre ratios of 1:1 were incorporated in the polypropylene matrix. Tensile, flexural, impact and hardness tests of the composites were subsequently carried out. The two combinations showed opposite trends for tensile strength and impact strength and similar trends for Young’s modulus, elongation, flexural properties and hardness. Tensile strength of the onion root containing composites increased with an increase of fibre loading, while in the nylon containing composites, tensile strength decreased with an increase in fibre loading. Their Young’s modulus increased and % elongation decreased with an increase in fibre content. Both flexural strength and flexural modulus increased with an increase in fibre content in both combinations. The impact strength of the onion root containing composites decreased with an increase in fibre loading, while the nylon containing composites showed the opposite trend. The hardness of both combinations increased with an increase in fibre content. The best set of properties were found at 15 wt% fibre loading in the nylon-broom grass-PP hybrid composite.

Effects of fiber hybridization on mechanical properties and autogenous healing of alkali-activated slag-based composites

This paper investigated the effects of hybrid fiber-reinforcement on the mechanical properties and autogenous healing ability of alkali-activated slag (AAS) composites. Three composites with varying quantities of fibers were investigated using a comprehensive set of experiments including mechanical behavior characterization, autogenous healing measurement, and microscopic characterization of healing products were performed. The experimental results showed that for the same total fiber volume fraction, the AAS composite using hybrid PE-PVA fibers achieved higher tensile strain capacity than the mixture using only the PE fibers. In terms of crack width reduction, stiffness restoration, and tensile recovery, the composite reinforced by hybrid PE-PVA fibers showed superior healing performance than that of the composite reinforced with only PE fibers. Even at a small volume fraction of 0.25%, the PVA fibers had an influence on the nature of the healing products.

The Influence of the Hybridization of Steel and Polyolefin Fiber on the Mechanical Properties of Base Concrete Designed for Marine Shotcreting Purposes

The present study investigated the influence of the hybridization of steel and polyolefin fiber on the mechanical performance and chloride ion penetration of base concrete designed for marine shotcreting purposes. The purpose of fiber hybridization is to reduce the risk of corrosion that might occur during service life. Sets of hybrid fiber reinforced base concrete, whose water to binder ratio was 0.338, were prepared. The fiber contents in the base concrete were 0.54 and 1.08 vol%, and the volume proportion of polyolefin fiber in the hybrid fiber varied from 0 to 100%. Although the effect of fiber hybridization was not clearly observed from the compressive strength, a synergetic effect which increased both the flexural strength and toughness occurred at a fiber content of 1.08 vol%. The optimum ratio of steel and polyolefin fiber was 50:50. With respect to chloride ion penetration, an increasing amount of steel fiber increased the amount of current passing through the base concrete specimen due to the presence of electrically conductive steel fiber. However, chloride ion diffusivity was not greatly affected by the presence of steel fiber.

Effect of Hybridization on Flexural Performance of Unidirectional and Bidirectional Composite Laminates under Ambient Temperature

Abstract. Fibre Reinforced Plastic (FRP) materials are widely used in several key engineering applications such as ships, aircraft, wind turbine blades, helicopter blade, automobiles, and other transportation vehicles because of their mechanical properties and tailoring capabilities.Carbon and glass fibres are the most popular fibre reinforcements used for composite components. In the present study, two different stacking sequences, (0 degrees) and (0/90 degrees), are selected to study effect of fibre hybridization on flexural performance using three-point bending tests. Materials used are E-glass and T-300 carbon fibres in an epoxy matrix and the laminates were produced by resin transfer moulding methods. Fracture surfaces of composite laminates were examined using a scanning electron microscope. The results showed that the flexural strength, modulus and strain at failure of unidirectional and bidirectional composite laminates were strongly influenced by stacking sequences, fibre orientation and the hybrid ratio of the fibres. A higher flexural modulus was achieved when carbon fibres were placed on the compressive side. Hybrid specimens showed higher flexural strength and modulus by 21.08% and 145.39%, respectively, compared to the pure glass fibre reinforced laminates. On the other hand, flexural strength and modulus of hybrid specimen were less by 6.50% and 8.20%, respectively, as compared to carbon fibre reinforced specimens. Stacking sequences and hybrid ratio of glass/carbon fibre reinforced specimens were investigated with a view towards improving the mechanical properties of hybrid composites.

Effect of fiber hybridization on mechanical, thermal, and water absorption behavior of HF/CF/HDPE composites

The composite materials are present in nature since the prehistoric era. Applications of fiber-based composite materials are increasing day by day in our society to overcome the raised environmental and economic concerns. Hence, waste fiber can be utilized as the best resource to develop composites. The present study deals with the impact of hybridization on the mechanical, thermal, and water absorption behavior of hair and coir fiber-based hybrid composites. The compression molding technique was used to develop the hybrid composites with fixed fiber content (15 wt.%) and was also varied the relative weight percentage of hair and coir fibers [(100% HF), (75% HF/25% CF), (50% HF/50% CF), (25% HF/75% CF) and (100% CF)] in reinforcing phase with HDPE composites S1, S2, S3, S4, and S5, respectively. The composite S2 was achieved superior mechanical attributes as compared to other hybrid/non-hybrid composites. The composite S2 was improved the tensile strength 5% and 35.2% more in comparison to composites S1 and S5, respectively. The thermal behavior (TGA, DTG, and DTA) was also influenced by the blending ratio of fibers of composites. The 5% and 50% weight losses of composite S2 were observed at higher temperature 343.8°C and 465.8°C as compare to other composites, which showed the thermal stability of composites S2. SEM analysis was used to investigate the strength of the fiber-matrix interface, which was shown a significant connection between mechanical and thermal behaviors. The crystallinity of hybrid and non-hybrid composites was examined by using the X-ray diffraction (XRD) analyzer and composite S2 was achieved 326 × 10−9 m crystal size at 21.053° peak position with wavelength 1.5406 × 10−10 m for Cu. The water absorption test was used to examine the moisture resistivity of composite materials, which was helpful to increase the applications of materials in humid areas.

Effect of fiber content and their hybridization on bending and torsional strength of hybrid epoxy composites reinforced with carbon and sugar palm fibers

This study aims to investigate the effect of fiber hybridization of sugar palm yarn fiber with carbon fiber reinforced epoxy composites. In this work, sugar palm yarn composites were reinforced with epoxy at varying fiber loads of 5, 10, 15, and 20 wt % using the hand lay-up process. The hybrid composites were fabricated from two types of fabric: sugar palm yarn of 250 tex and carbon fiber as the reinforcements, and epoxy resin as the matrix. The ratios of 85 : 15 and 80 : 20 were selected for the ratio between the matrix and reinforcement in the hybrid composite. The ratios of 50 : 50 and 60 : 40 were selected for the ratio between sugar palm yarn and carbon fiber. The mechanical properties of the composites were characterized according to the flexural test (ASTM D790) and torsion test (ASTM D5279). It was found that the increasing flexural and torsion properties of the non-hybrid composite at fiber loading of 15 wt % were 7.40% and 75.61%, respectively, compared to other fiber loading composites. For hybrid composites, the experimental results reveal that the highest flexural and torsion properties were achieved at the ratio of 85/15 reinforcement and 60/40 for the fiber ratio of hybrid sugar palm yarn/carbon fiber-reinforced composites. The results from this study suggest that the hybrid composite has a better performance regarding both flexural and torsion properties. The different ratio between matrix and reinforcement has a significant effect on the performance of sugar palm composites. It can be concluded that this type of composite can be utilized for beam, construction applications, and automotive components that demand high flexural strength and high torsional forces.

Effect of Fibres on the behaviour of Bottle shaped strut

Bottle-shaped struts are the critical elements in the design of D-regions using Strut-and-Tie method. The transverse tension develops due to dispersion of compression load which further leads to splitting crack in bottle shaped strut. Due to this, the strut fails before reaching its ultimate compression capacity. Higher resistance to the transverse tension can improve the strut capacity and its efficiency in load transfer. Transverse tensile stress can be resisted by providing the steel reinforcement or through the addition of discrete fibres in the concrete. Many international codes like ACI, AASTHO, and CSA have suggested guidelines about the addition of steel fibre reinforcement in the bottle-shaped struts for resisting the transverse tension. Still, the influence of the discrete fibres on the performance of the bottle-shaped strut is not well established. The performance of the bottle-shaped strut in terms of efficiency factors, crack pattern and failure mode for different amounts of macro steel fibres and micro polypropylene fibres are studied using experimental investigation. Specimens of 600mm x 600mmx 100mm size were tested under compression. Steel fibres are added in the proportions of 0.7%, 0.9% and 1.1% volume fractions to the concrete. Effect of fibre hybridization also studied by adding micro polypropylene fibres in the proportions of 1% and 2% in addition to the steel fibres. Experimental results showed that adding discrete fibres in concrete significantly improved the resistance to the transverse tension in bottle-shaped struts and led to the increased load-carrying capacity of the specimens. A 75% improvement in the efficiency factor is observed at 0.9% volume of steel fibre addition. Addition of micro polypropylene fibres to the macro steel fibres further enhanced the load-carrying capacity of the bottle-shaped struts. Microfibres in the concrete effectively arrested the micro-cracks and delayed the occurrence of a first splitting crack in the strut region. Due to this the mode of failure changed to ductile through the formation of a greater number of small cracks with less crack width at the ultimate load. Results of this study clearly show that the addition of discrete fibres to the concrete is an effective solution to improve the performance of the bottle-shaped struts in terms of ultimate strength and serviceability.