Effect Of Fiber Reinforcement Research Articles

Study of mechanical properties of composite materials reinforced with aluminum fibers

This study investigates the mechanical properties of composite materials reinforced with aluminum fibers of varying lengths and concentrations. The research aims to evaluate the effects of fiber reinforcement on both flexural and compressive strengths, using fibers of three distinct lengths (2×20 mm, 2×30 mm, and 2×40 mm) and four different concentrations (0.5%, 1%, 1.5%, and 2%) by weight within the composite matrix. Mechanical tests were performed after 28 and 56 days of curing to assess the influence of fiber reinforcement over time. The results demonstrate that increasing fiber length and concentration generally improves the flexural and compressive strengths, with the most notable gains observed at moderate fiber content. However, the study also finds that excessively high fiber percentages may lead to diminishing returns in strength performance, possibly due to fiber agglomeration or stress concentration effects. These findings provide valuable insights into optimizing the design of fiber-reinforced composite materials for various structural applications, enhancing both performance and material efficiency.

Enhancing concrete beam performance with PVA fibers, coal ash, and graphene fabric: a comprehensive structural analysis

ABSTRACT This study evaluates the structural performance of Polyvinyl Alcohol Cementitious Composites (PVCC)-layered reinforced concrete beams with coal ash under static loading. Experimental investigations included first crack load, ultimate load, load-deflection behavior, ductility, stiffness, and energy absorption. Results highlight the influence of Polyvinyl Alcohol-(PVA) fiber dosage on structural behavior. The control specimen exhibited an initial crack load of 80kN, with subsequent specimens showing varied crack initiation loads influenced by PVA fiber content. Optimal performance was observed at 1.2% PVA fiber dosage, with higher dosages leading to earlier crack initiation. Ultimate load carrying capacity increased with PVA fiber addition, reaching a peak at 1.2% dosage before slight decreases occurred with higher dosages. Load-deflection behavior demonstrated the superior performance of PVCC layered beams, particularly specimen BP3, attributed to optimal fiber content. Ductility, stiffness, and energy absorption increased with PVA fiber reinforcement, with 1.2% dosage yielding optimal results. Excessive fiber content led to diminishing returns. Energy index analysis revealed superior energy dissipation in specimens with higher PVA fiber content, emphasizing the effectiveness of fiber reinforcement in enhancing structural performance. Overall, the study underscores the importance of optimizing PVA fiber dosage to maximize structural resilience and load-bearing capacity in PVCC-layered concrete beams with coal ash.

Effect of recycled polyester fiber reinforcement on the mechanical behavior and microstructure of red mud-improved volcanic ash

Effect of recycled polyester fiber reinforcement on the mechanical behavior and microstructure of red mud-improved volcanic ash

Experimental and simulation study on seismic performance of seawater sea-sand PVA cementitious composite columns with GFRP bars

The seismic properties of seven seawater sea-sand (SWSS) PVA cementitious composite columns with Glass Fiber Reinforced Polymer (GFRP) bars were studied. The effects of four parameters, namely polyvinyl alcohol (PVA) fiber content, axial compression ratio, cementitious composite strength and stirrup spacing, on the seismic performance of composite columns were analyzed. The failure of the specimen was observed, and the hysteresis curve, skeleton curve, stiffness degradation, energy dissipation capacity, ductility and strain of the specimen were analyzed. The test results show that the large chip-based spalling will occur when the specimen without fiber incorporation is damaged, and the incorporation of PVA fiber, the reduction of stirrup spacing and the reduction of axial compression ratio will delay the rate of crack formation and development. In addition, through cross-section analysis and considering the reinforcement effect of PVA fibers, a proposed formula for calculating the horizontal bearing capacity of composite columns is proposed. Finally, the finite element model of SWSS PVA cementitious composite columns with GFRP bars is established, and it is found that increasing the strength grade of cementitious materials can greatly improve the seismic performance of composite columns. The conclusions could be references for the engineering application. In the context of the global emphasis on green development and environmental protection, seawater and sea-sand cementitious composites and components with fiber reinforcement will have a wide range of application prospects in the construction of coastal areas.

Effect of Fibre Reinforcement on Compressive Strength and Compressive Modulus of Epoxy Granite

Abstract The main focus of the paper is to study the effect of fibre reinforcement on compressive strength and compressive modulus of epoxy granite. To investigate the effect of fibre reinforcement, two compositions were considered likes 20% Epoxy and 80% Granite without fibre reinforcement and 20% Epoxy, 75% Granite and 5% fibre reinforcement. Based on the literature studied, three types of fibre were considered viz. steel fibre, carbon fibre and basalt fibre. Three specimens of each type of fibre i.e. nine specimens and three specimens without fibre reinforcement were prepared. The obtained maximum compressive strength and compressive modulus of epoxy granite without reinforcement is 91.70 MPa and 3.5 GPa for the composition of 20% epoxy and 80% granite. The observed maximum compressive strength of 78.57 MPa for 20% epoxy and 75% granite with 5% carbon fibre reinforcement epoxy granite (CFEG) which is much higher than steel fibre reinforced epoxy granite (SFEG) with 20% epoxy and 75% granite and basalt fibre reinforced epoxy granite (BFEG) with 20% epoxy and 75% granite. The computed compressive modulus is 2.7 GPa for SFEG with 5% fibre which greater than CFEG and BFEG with the same fibre content.

Evaluating the effect of Incorporating Chicken Feather Fibers on the Technological Properties of Eco-Friendly Compressed Earth Bricks

This paper investigates the feasibility of improving the performance of raw bricks by using chemically treated chicken feather fibers as a sustainable reinforcement material. Although numerous studies have already explored the use of chicken feathers in brick composites, this work is distinguished by the application of a novel chemical treatment involving formaldehyde and silane to enhance the fibers' compatibility with the clay matrix. The treated fibers were incorporated into raw brick samples at varying concentrations. The effects of fiber reinforcement on critical properties such as porosity, bulk density, compressive strength, and thermal conductivity were systematically analyzed. The results indicate that incorporating chemically treated chicken feather fibers reduces porosity and bulk density while increasing compressive strength within an optimal concentration range. Additionally, a significant reduction in thermal conductivity was observed, demonstrating the potential of these materials to improve thermal insulation in construction applications. This study highlights the promise of utilizing chicken feather waste, treated with formaldehyde and silane, as reinforcement in the production of eco-friendly bricks, with implications for sustainable construction practices.

Dynamic properties of CO2-cured foam concrete at different loading rates: Effect of the foam admixtures and addition of polypropylene fiber

This paper investigated the dynamic mechanical properties of CO2-cured foam concrete under varying conditions, focusing on the effects of foam admixture and fiber reinforcement. The study tends to enrich the knowledge regarding the performance of CO2-cured foam concrete under different loading rates, especially in relation to density and matrix strength. The foam admixture of the specimens ranges from 26% to 55%, achieving density from 600 kg/m3 to 1,000 kg/m3. The specimens were loaded at strain rates from 80 s-1 to 398 s-1. Experimental results revealed the dynamic elastic modulus, dynamic compressive strength, and Dynamic Increase Factor (DIF) showed a strong correlation with the foam admixture and density. In addition, the incorporation of polypropylene (PP) fibers effectively improved the mechanical behavior of the foam concrete, achieving up to a 17% increase in dynamic compressive strength. This comprehensive analysis highlights the critical role of foam admixture and fiber reinforcement in determining the dynamic properties of CO2-cured foam concrete and provides valuable insights for optimizing the dynamic performance of foam concrete in various construction applications.

Coupling Effect of Natural Enzymes and Fiber Reinforcement on Strength Response of Soil

Coupling Effect of Natural Enzymes and Fiber Reinforcement on Strength Response of Soil

Mechanical properties and ductility improvement mechanisms of fiber-reinforced biomimetic mineralized composites using sea sand

Biomimetic mineralized composites (BMC) is an emerging green cementing material. However, the application of BMC is limited by brittle failure. This study proposes novel fiber-reinforced biomimetic mineralized composites (FRBMC) with excellent ductility based on the coupling method of fiber reinforcement and biomimetic chemically induced calcium carbonate precipitation (BCICP). Three typical fibers, including polymer fibers (polypropylene fiber, PF), mineral fibers (basalt fiber, BF), and plant fibers (coir fiber, CF), were used to explore the feasibility of application in FRBMC. Accordingly, mechanical properties, pore structures, and microscopic characteristics were assessed through unconfined compressive strength (UCS) test, mercury intrusion porosimetry (MIP) tests, and scanning electron microscopy (SEM). The results show that fiber induces a transition from brittle to ductile failure modes in BMC. PF exhibits the most notable enhancement in residual strength and peak strain, while BF leads to the highest compressive strength. CF can effectively enhance energy absorption after reaching peak stress. Moreover, FRBMC with CF contains a higher quantity of minute pores, while BF can reduce the porosity of FRBMC. The calcium carbonate crystals effectively cement fibers and sand particles, enhancing the ductility of FRBMC through forming various cementing structures. This study investigates the synergistic effect of BCICP and fiber reinforcement, providing valuable guidance for potential practical applications of FRBMC.

Hybrid fiber reinforced ultra-high performance coal gangue geopolymer concrete (UHPGC): Mechanical properties, enhancement mechanism, carbon emission and economic analysis

The low carbonization of ultra-high performance concrete (UHPC) has become a hot topic for sustainable development in the construction industry. Calcined coal gangue was used as aggregate and binder to prepare ultra-high performance coal gangue geopolymer concrete (UHPGC) in this paper. The hybrid reinforcement effect of steel fibers, calcium carbonate whiskers (CW), and carbon nanotubes (CNTs) on UHPGC was studied in the experiment. The results indicated that when the mixing ratio of straight steel fibers and hooked-end steel fibers was 2:1, the 28 d-compressive strength of UHPGC reached 145.94 MPa. However, excessive hooked-end steel fibers deteriorated the reinforcement effect of adjacent fibers and reduced the mechanical properties of UHPGC. CW and CNTs had a more significant improvement in the flexural properties of UHPGC. The bridging effect of CNTs and CW dispersed the stress on the matrix and delayed the formation and development of micro-nano cracks. Meanwhile, CNTs and CW improved the fiber bridging energy dissipation, thereby improving the flexural properties of UHPGC. The UHPGC had the highest flexural strength and flexural deflection of 13.59 MPa and 4.12 mm, respectively. The UHPGC prepared in this paper had lower carbon emissions and economic costs compared to traditional UHPC. Overall, this study provided valuable references for the resource utilization of coal gangue and the multi-scale strengthening and toughening of UHPGC.

Mechanical strength of rubberized concrete: Effects of rubber particle size, content, and waste fibre reinforcement

Concrete production, ubiquitous in global construction, exerts significant environmental strain, notably through cement manufacturing's carbon footprint and natural sand depletion. As a response, researchers are exploring eco-friendly alternatives, including Waste Tyre Rubber (WTR) aggregates which replace natural sand in concrete. This study investigates the impact of WTR particle sizes (ranging from 0.2 to 4 mm) and volumetric replacements (0–54 %) on Rubberised Concrete Mortar (RuCM) and Rubberised Concrete (RuC) mechanical properties. Additionally, Waste Tyre Steel Fibre (WTSF) reinforcement effects (volume dosage between 0 % and 3 %) are examined and compared with Commercial Steel Fibre (CSF). The study optimizes RuCM and RuC mixes via particle packing theory, incorporating Ground Granulated Blast Furnace Slag (GGBS) and Fly Ash (FA) as cement replacements. Mechanical tests reveal the compressive and flexural strength reduces with an increasing WTR dosage, attributed to the inherent softness of WTR and the weak interfacial bonding between WTR particles and surrounding matrix. Utilizing an optimized RuC mixture with a 10 % WTR replacement yields substantial mechanical improvements, showcasing a remarkable 195 % surge in compressive strength and a noteworthy 61 % elevation in flexural strength over conventional concrete (CC). However, when compared to the control mix devoid of rubber replacement, there is a modest reduction of 16 % in compressive strength and 4 % in flexural strength. Moreover, the incorporation of WTSF reinforcement proves beneficial in mitigating compressive strength losses post rubber particle inclusion and brings about a substantial increase in flexural strength with 3 % volumetric additions. Quantitative analysis reveals the reinforcement effect from WTSF is comparable to the effect of CSF reinforcement. These findings underscore the intricacies and potential opportunities in harnessing WTR and WTSF for the development of resilient and sustainable concrete formulations.

Effect of Glass Fiber Reinforcement on Bearing Capacity and Settlement of Foundations on Soft Clay

Effect of Glass Fiber Reinforcement on Bearing Capacity and Settlement of Foundations on Soft Clay

Influence of Polymer Fibre Reinforcement on Concrete Anchor Breakout Failure Capacity.

With the increasing use of fibre-reinforced concrete, e.g., in industrial floor and tunnel construction, the associated fastening technology in this material has increasingly become the focus of scientific attention in recent years. Over 25 years ago, design and assessment guidelines for anchoring systems in reinforced concrete were established, which have since evolved into comprehensive regulatory standards. However, these standards only address plain and rebar-reinforced concrete as anchoring bases, neglecting fibre-reinforced concrete. The design of anchorage systems in fibre-reinforced concrete has not yet been standardised. Recent studies and product certifications accounting for steel fibre reinforcement are now seeing their way to publication, supported by a fair amount of scientific research studies. This paper aims to elucidate the effects of polymer fibre reinforcement in this application through a systematic investigation. Experimental studies were conducted to evaluate the system's load-bearing behaviour failing with concrete breakouts under tensile loading. By incorporating the determined material properties of polymer fibre-reinforced concrete and their mathematical interpretation, alternative model proposals are presented to assess concrete breakout resistance. The addition of polymer fibres significantly improves the load-bearing capacity and ductility of concrete under tensile loads, transforming its quasi-brittle response into a more ductile behaviour. Although the fibres had a minor impact on overall material strength, their influence on the tensile capacity of the anchors reveal a 15-20% increase in load resistance and up to a doubling of the failure displacements.

Effects of perlite content and jute fiber reinforcement on flexural behavior of the gypsum/perlite composite core-based sandwich structures

Gypsum wallboards are widely used as a building material, but limitations exist in their weight and brittleness. The incorporation of various fillers in the gypsum makes them lightweight, stiff, and capable of resisting catastrophic failure but with the cost of strength. Sandwiching the filled gypsum using a low-cost material as skin may be an innovative approach to improve the flexural properties. In this work, sandwich structures were fabricated using jute fiber reinforced and unreinforced perlite-filled gypsum as cores and low-cost brown paper as skins. The density, flexural strength, modulus, and toughness of the resulting sandwich structures were investigated. It is found that the increase in perlite content in pure gypsum and jute fiber-reinforced gypsum significantly enhances the flexural strength, modulus, and toughness of the sandwich structures. However, previous research on jute fiber-reinforced and unreinforced gypsum/perlite composite panels (without skin) showed a decrease in flexural strength due to an increase in perlite content. The maximum flexural strengths of unreinforced sandwich (URS) and jute fiber reinforced sandwiches (JRS) at a perlite content of 15 g are found to be 13.29 % and 40.79 % greater than the control sandwich with pure gypsum core. The maximum flexural toughness of the JRS at a perlite content of 20 g and that of the URS at a perlite content of 15 g are respectively 118.31 % and 79.14 % greater than the control sandwich. A significant difference in load-displacement curves between JRSs and URSs is noticed despite the similar failure sequence i.e. core cracking→skin yielding→skin tearing.

Mechanical Behavior of Low-Strength Hydraulic Lime Concrete Reinforced with Flexible Fibers under Quasi-Static and Dynamic Conditions

We investigate the effect of flexible fiber reinforcement on low-strength hydraulic lime concrete. This type of concrete is occasionally necessary to ensure compatibility with the substrate, particularly in the conservation and rehabilitation of historical heritage. For this purpose, we designed a matrix of hydraulic lime concrete based on a mix design method we proposed previously and added different amounts of polyvinyl alcohol fiber (volumetric contents of 0.3%, 0.6%, 0.9%, and 1.2%). We then conducted three-point bending tests on prismatic specimens with a central notch under quasi-static (displacement rate of 4 × 10−4 mm/s) and dynamic (4 mm/s) conditions, using a servo-hydraulic machine. The results indicate that, in both quasi-static and dynamic regimes, the flexural strength, the residual flexural strengths for different crack openings, and the work of fracture increase as the fiber content increases. Furthermore, transitioning from one regime to another (by increasing the strain rate or velocity) leads to a significant increase in these mechanical parameters.

Mechanism analysis on tensile fracture properties of heterogeneous BFLAC at cryogenic temperature: Experimental investigation and mesoscale simulation

This study aims to investigate the tensile failure behaviours and corresponding fracture mechanisms of basalt fiber reinforced lightweight-aggregate concrete (BFLAC) at various temperatures via a comprehensive cryogenic tests and mesoscale simulations, with a special focus on the quantitative effects of cryogenic temperature and fiber volume fraction. Firstly, Macro- and micro-scale split-tensile tests of BFLAC with fiber volume fractions of 0.0–0.3 % at 20∼-90 °C were conducted. Secondly, a two-steps sequentially thermo-mechanical coupled meso-scale analysis approach with explicit modelling of fibers and pore ice was developed to simulate the corresponding direct-tensile failures of BFLAC with more fiber volume fractions. The results show that as the temperature falls from 20 °C to −90 °C, the dominant action mechanism of basalt fibers changes from Mode-1 (pull-out of fibers) to Mode-2 (rupture of fibers) due to the ice formation and the interactions between meso-components. Tensile strengths of BFLAC present a significant low-temperature enhancing effect, with a maximum increase of 90 % for direct-tensile strength while 104 % for split-tensile strength. Besides, as the temperature drops, although a larger proportion of fibers are in a low bridging stress state and a smaller proportion reach yield stress for rupture, the average fiber stress increases and the utilization degree of fibers with more stresses transferred improves, which results in that the fiber reinforcement effect is strengthened. Finally, based on experimental and numerical results, the quantitative relationships between split-tensile and direct-tensile strengths at different cryogenic temperatures were given. The present research results can better understand the cryogenic mechanical properties of BFLAC, which have important reference value for its extensive promotions and applications in engineering structures exposed to extreme low-temperature environments.

Effect of different fiber reinforcements on the strength and acid attack resistance of alkali-activated concrete

The study analyzes the effect of steel, polyvinyl alcohol (PVA), polypropylene (PP), and glass fiber reinforcements in alkali-activated concrete (AAC) by conducting various mechanical strength tests. The fiber dosages are maintained at 0.1-0.3% by volume of AAC. Furthermore, the study evaluates the effect of acidic exposures on the strength of fiber-reinforced alkali-activated concrete (FRAAC) by immersing the samples in 10% v/v solutions of HCl. H2SO4 and HNO3 for 28 days. The findings revealed that fiber additions improved the compressive and flexural strength properties by up to 13% and 27%, respectively, while the modulus of elasticity improved significantly by up to 52%. Acid attack tests on AAC specimens demonstrated H2SO4 to be highly detrimental to the mechanical and chemical properties of AACs. The strength loss in FRAAC after acidic exposures was up to 50% lesser as compared to the plain mix. Glass-FRAACs were found to be highly resistant to acid attack, whereas steel-FRAACs had a relatively lesser resistance. These findings were further validated by the SEM micrographs, XRD, and FTIR analyses, which depicted the changes in the microstructure of the specimens subjected to acidic environments. Overall, fiber reinforcements improve the mechanical and durability properties of AACs.

Effect of steel fiber content on failure strength and toughness of UHPC-CA at low temperature: An experimental investigation

As a potential and sustainable construction material, ultra-high performance concrete containing coarse aggregate (UHPC-CA) finds promising applications in engineering constructions, particularly in severe cold regions. This study conducts an experimental study to investigate the influence of fiber content (ranging from 0.0 % to 3.0 %) on the uniaxial compression and splitting-tension failures of UHPC-CA across a temperature range of −90 °C∼20 °C. Through microstructure analysis, the underlying mechanisms and quantitative analysis behind the low-temperature enhancement effect and fiber reinforcement effect on the nominal strength and toughness of UHPC-CA were elucidated. The test results show that as the temperature drops from 20 °C to −90 °C, nominal strengths of UHPC-CA monotonically increase (with a maximum increase 88.1 % for splitting-tension strength while 72.6 % for compressive strength), but the compressive toughness reduces with a maximum decrease 54.6 %. Additionally, the incorporation of steel fibers can enhance the nominal strengths and compressive toughness, exhibiting the fiber reinforcement and toughening effects. Compared to the UHPC matrix, all the increases for nominal strengths and compressive toughness of UHPC-CA with 2.0 % steel fibers at room temperature are higher than those at low temperatures, demonstrating that the decreasing temperature can weaken the fiber reinforcement and toughening effects, which may attribute to fact that the formation of microcracks (due to the expansion of phase change of pore ice) in the surface between steel fiber and UHPC matrix at low temperatures, as observed in the microscopic test. However, as the fiber content exceeds 2.0 %, the splitting-tension strength decreases, thereby it is recommended that the optimal steel fiber content is around 2.0 % for UHPC-CA at low temperatures. Finally, considering the quantitative effects of steel fiber characteristics and temperature, the empirical prediction models for cryogenic nominal strengths were proposed and verified, which can well predict compressive and splitting-tension strengths of UHPC-CA with various steel fiber contents at low temperatures. This study can provide an experimental data reference for the safety design of UHPC structures and contribute to promoting the application of UHPC-CA in the engineering construction of cold regions.

Experimental assessment of modal properties of hybrid CFRP-timber panels

Hybrid timber composites are becoming increasingly widespread to efficiently enhance timber performance. While carbon fibre reinforcement has been explored for strength in timber structures, its impact on vibration performance remains understudied and is crucial as mass timber buildings extend their spans and heights. This work explores the effect of carbon fibre reinforcement on the vibration performance parameters of CLT floor systems. Natural frequency, mode shape, damping and stiffness parameters are evaluated from experimental testing using the Natural Excitation Technique (NExT) combined with the Eigensystem Realization Algorithm (ERA) and robust techniques for selection of physical dynamic properties, verified against numerical finite element models. The findings reveal that, in the case of three-ply Cross-laminated Timber (CLT) panels with depths ranging from 115 mm to 135 mm, introducing reinforcement at ratios below 0.67% led to an enhancement in frequencies, registering an increase of 6% to 11%, although not explicitly accounting for changes in environmental conditions. Moreover, these reinforced panels showed a relevant increase in effective flexural stiffness, ranging from 15% to 22%, when compared to their unreinforced counterparts. This means an improved maximum span of around 4%–6% within current design limits for timber floors influenced by vibration performance. These findings enhance the understanding and design of high-performance composite timber floors, promoting the use of renewable building materials in construction.

Bending Strength of Continuous Fiber-Reinforced (CFR) Polyamide-Based Composite Additively Manufactured through Material Extrusion.

This paper shows the three-point bending strength analysis of a composite material consisting of polyamide doped with chopped carbon fiber and reinforced with continuous carbon fiber produced by means of the material extrusion (MEX) additive manufacturing technique. For a comparison, two types of specimens were produced: unreinforced and continuous fiber-reinforced (CFR) with the use of carbon fiber. The specimens were fabricated in two orientations that assure the highest strength properties. Strength analysis was supplemented by additional digital image correlation (DIC) analysis that allowed for the identification of regions with maximum strain within the specimens. The utilization of an optical microscope enabled a fractographic examination of the fracture surfaces of the specimens. The results of this study demonstrated a beneficial effect of continuous carbon fiber reinforcement on both the stiffness and strength of the material, with an increase in flexural strength from 77.34 MPa for the unreinforced composite to 147.03 MPa for the composite reinforced with continuous carbon fiber.