Glass Fiber Research Articles

A Review of Fatigue Performance of Fiber Mixture with Concrete

The fatigue performance of fiber reinforced concrete is a research hotspot in the field of civil engineering. This paper systematically reviews the related research. The fatigue performance of fiber reinforced concrete is different from that of ordinary concrete because the internal structure is changed by the addition of fiber. Different kinds of fibers have different effects on fatigue performance. Steel fiber can enhance the toughness of the matrix, effectively hinder crack propagation, and significantly improve the fatigue life. Synthetic fibers have obvious effects in inhibiting early microcracks, and the mixed use of the two will produce complementary phenomena. Among them, steel fiber has the greatest improvement in the mechanical properties of concrete, with an average increase of 30.5%-41.7%. Glass fiber and synthetic fiber have improved the mechanical properties of concrete, with an increase of 10.5%-14.6%. Among them, the improvement of mixed fiber is significantly higher than that of single fiber and the mechanical properties are improved by about 45%-59.2%. The existing research mostly focuses on experimental analysis, numerical simulation is relatively less, and the research on long-term fatigue performance in practical engineering applications is still insufficient. In the future, it is necessary to strengthen multi-scale research, improve numerical models, and deeply explore its fatigue behavior in complex environments, so as to provide more solid theoretical support for engineering applications.

Effect of Water Immersion and Freeze-Thaw Cycles on Pull-off Strength of FRP Epoxy Bonded on Concrete: An experimental study

The durability and performance of Fiber Reinforced Polymer (FRP) composites for strengthening reinforced concrete structures under various environmental conditions are critical for their long-term efficacy. This study investigates the effects of water immersion and freeze-thaw cycles on the pull-off strength of epoxy-bonded FRP concrete slabs, simulating conditions typical for waterfront structures such as piles, beams, and decks. Concrete slabs, fabricated to EN 1766 standards, were reinforced with Basalt (BFRP), Glass (GFRP), and Carbon Fiber Reinforced Polymer (CFRP) sheets using Duratek® AV21 epoxy resin. The samples were conditioned in a controlled laboratory environment (23±2°C, 50±5% RH) for 24 hours before being subjected to water immersion and freeze-thaw cycling tests. Pull-off tests, conducted per EN 1542, revealed cohesive failures in the concrete substrate. The average pull-off strength for the control samples was 3.26 N/mm² for concrete and 3.97 N/mm² for epoxy resin. Water immersion results showed a slight decrease in pull-off strength for CFRP and GFRP, by 9% and 2% respectively, while BFRP exhibited a 14% increase. Freeze-thaw cycling led to increased pull-off strength across all FRP types: 7% for GFRP, 7.3% for BFRP, and 3.75% for CFRP. The findings indicate that water immersion and freeze-thaw conditions have a marginal impact on the pull-off strength of FRP-reinforced concrete. Despite the environmental exposure, all test results remained above the required pull-off strength of 2.5 MPa, demonstrating the robustness of the FRP-concrete bond. The study supports the use of FRP composites for structural reinforcement in harsh environments, highlighting their resilience under adverse conditions. Further research is recommended to explore long-term performance and additional environmental factors to ensure comprehensive durability assessments of FRP-reinforced systems.

Effect of Manufacturing Parameters on Low-Velocity Impact Behavior of Aramid, Carbon and Glass Fiber Reinforced Polymer Composites Using Taguchi Experimental Design

Effect of Manufacturing Parameters on Low-Velocity Impact Behavior of Aramid, Carbon and Glass Fiber Reinforced Polymer Composites Using Taguchi Experimental Design

Properties of High-Strength Concrete Incorporating Calcined Diatomaceous Earth, Polypropylene, and Glass Fibers

This study was aimed at determining the hardened and fresh properties as well as the high-temperature resistance of high-strength concrete (HSC) produced by incorporating diatomaceous earth, polypropylene, and glass fibers. CDE (calcined diatomaceous earth) was employed as a 10% cement replacement, while polypropylene and glass fibers were added separately to the mixtures at 0.2, 0.4, 0.6, 0.8, and 1.0% volumetric contents. Moreover, the mixtures without using CDE and fibers were used as references. The concrete mixtures were fabricated, followed by the determination of the fresh concrete flow, the absorption capacity, and the flexural, compressive, and splitting tensile strengths of hardened concrete. Furthermore, the specimens fabricated for the hardened concrete were exposed to temperatures of 400 °C, 500 °C, and 600 °C, and the remaining compressive strength was examined. The findings suggested that the incorporation of polypropylene and glass fibers in HSC with CDE enhanced the compressive, flexural, and splitting tensile strengths by 23.4 and 32.6%, 70.0 and 83.5%, and 18.9 and 17.9%, respectively. Moreover, the inclusion of polypropylene and glass fibers reduced the absorption of hardened concrete. Meanwhile, the inclusion of CDE lowered the strengths and increased the absorption. It was further identified that the incorporation of CDE enhanced the resistance of HSC to high temperatures, while polypropylene and glass fibers lowered the resistance. The incorporation of CDE, polypropylene, and glass fibers also lowered the flow of fresh concrete.

Enhancing Polylactic Acid (PLA) Performance: A Review of Additives in Fused Deposition Modelling (FDM) Filaments

This review explores the impact of various additives on the mechanical properties of polylactic acid (PLA) filaments used in Fused Deposition Modeling (FDM) 3D printing. While PLA is favored for its biodegradability and ease of use, its inherent limitations in strength and heat resistance necessitate enhancements through additives. The impact of natural and synthetic fibers, inorganic particles, and nanomaterials on the mechanical properties, printability, and overall functionality of PLA composites was examined, indicating that fiber reinforcements, such as carbon and glass fibers, significantly enhance tensile strength and stiffness, while natural fibers contribute to sustainability but may compromise mechanical stability. Additionally, the inclusion of inorganic particulate fillers like calcium carbonate improves dimensional stability and printability, although larger particles can lead to agglomeration issues. The study highlights the potential for improved performance in specific applications while acknowledging the need for further investigation into optimal formulations and processing conditions.

Premelted-Substrate-Promoted Selective Etching Strategy Realizing CVD Growth of High-Quality Graphene on Dielectric Substrates.

Direct chemical vapor deposition growth of high-quality graphene on dielectric substrates is a great challenge. Graphene growth on dielectrics always suffers from the issues of a high nucleation density and poor quality. Herein, a premelted-substrate-promoted selective etching (PSE) strategy was proposed. The premelted substrate can promote charge transfer from the substrate to the nuclei near graphene domains, thus facilitating the reaction between the CO2 etchant and the nuclei. Consequently, the PSE strategy can realize selective etching of nuclei formed near graphene domains to evolve high-quality graphene with a uniform domain size of ∼1 μm and an ID/IG ratio of ∼0.13 on glass fiber, achieving the largest domain size and the lowest defect density in graphene grown on a noncatalytic substrate without metal assistance. The largely improved quality of graphene significantly increases the electrical conductivity by 3 times and improves the working life by 7 times when applied as an electric heater compared with that fabricated without the PSE strategy.

THE EFFECT OF TRAVERTINE WASTE ON THE STRENGTH AND INSULATION PROPERTIES OF FOAM CONCRETE

Abstract Incorporating waste additives into foam concrete mixtures is a promising route to develop environmentally-friendly concrete production with tailored thermos-mechanical properties. In this paper, the effects of various fabrication parameters of foam concrete, including the type of waste additive, water/binder ratio, density of mixture, and incorporation of glass fibers were investigated. Foam concrete samples were fabricated using fly ash and travertine wastes, and the variations in their flexural strength, compressive strength, and thermal conductivity using various concrete mixture designs were measured. The obtained results show that foam concrete with fly ash additive tends to have higher compressive strength and thermal conductivity than foam concrete with travertine waste. However, the latter exhibits better thermal insulation properties, which tend to improve by adding glass fibers. This work defines the outlines for exploring the use of harmful wastes in fabricating foam concrete. It offers guidelines for developing improved foam concrete mixtures with tailored thermos-mechanical properties.

The impact of matrix viscosity on the mechanical behavior of fiber reinforced composites

AbstractThe influence of matrix viscosity on the mechanical behavior of fiber reinforced composites was investigated in this paper. The glass fiber fabric was selected as reinforcement and the mixed solution composed of resin, curing agent and different viscosity of diluent was selected as matrix. The composites was fabricated by vacuum‐assisted resin infusion (VARI). The influence of matrix viscosity on bending, impact and creep properties of composites were studied by varying the mass fraction of 1,4‐butanediol diglycidyl ether (BDDGE) diluent, the least square fitting was used to fit the experimental result. The mathematical model for characterizing the relationship between the matrix viscosity and the bending strength was established, and the mass fraction of BDDGE diluent based on the optimal bending property was obtained. The failure mechanisms were analyzed by analyzing fiber reinforced composites properties, reaction principles and fracture morphologies. Result shows that the epoxy groups within the viscosity undergo a ring‐opening reaction to integrate the cross‐linking network structure of the epoxy resin. However, an excessive amount of diluent will result in an increase of number of flexible chain segments, which initially enhancing the mechanical properties of the specimens before causing a subsequent decline. The mathematical model was substantiated by experiment, which reveals that the viscosity is 185.3 mPa·s for the optimal bending properties.Highlights The bending strength and modulus reached the maximum at a viscosity of 180 mPa·s The creep curves demonstrate progressive damage and minute deformation. The ring‐opening reaction occurs with two oxygen atoms in the diluent BDDGE. The matrix viscosity of BDDGE diluent is 185.3 mPa·s for the optimal bending properties.

Effects of Heat Transport Characteristics and Chemical Reaction in Unsteady Flow of Williamson Fluid and Entropy Generation: The Keller‐Box Numerical Scheme

ABSTRACTThe study of heat and mass transport in non‐Newtonian fluid flow over a stretching surface accompanying relevant characteristics is important in several engineering and industrial processes like annealing and thinning of copper wires, aerodynamic extrusion of plastic and rubber sheet, glass fiber, and so forth. Based on significant practical applications, the objective of this investigation is to assess the time‐dependent flow of Williamson fluid influenced by porous sheet stretching in exponential manner accompanied by thermal and mass transport and entropy generation. Various factors affecting fluid flow, thermal and mass transport (viscous dissipation, non‐linear radiation, porous media, chemical reaction, and heat source) are considered. The regulating PDEs are turned into ODEs in nondimensional form utilizing adequate similarity transformation relations. The problem is solved numerically on MATLAB adopting the Keller‐Box scheme. On fluid flow, temperature, and concentration distribution the effects of relevant parameters are depicted by drawing sketches and discussed. Besides, second law analysis is also evoked in the study in terms of entropy generation accompanying the Bejan number. Moreover, quantities of physical significance such as skin friction coefficient, Sherwood number, and Nusselt number are computed, compared with prior research and found in excellent agreement. It is concluded that temperature profile magnifies due to radiation and heat generation effects. The reaction coefficient and order of the reaction exhibited opposite effects on concentration profile. It is also concluded that entropy production reduces with increasing slips and temperature difference parameter, while opposite effect is observed due to Brinkman number. Furthermore, it is observed that skin‐friction coefficient at the surface decreases with velocity slip and non‐Newtonian parameter however, trend is reversed due to unsteadiness parameter. The results of the study may find applications of practical importance in engineering fields such as designing heat exchangers, cooling processes, improving energy storage systems, and so forth.

High-Resolution TG-TOFMS Coupled with Principal Component Analysis and Kendrick Mass Defect Analysis: Elucidation of Molecular-Scale Degradation Behavior of Glass Fiber Reinforced Polypropylene during Thermo-Oxidative Degradation.

This study presents a novel approach that combines thermogravimetric analysis with time-of-flight mass spectrometry (TG-TOFMS), principal component analysis (PCA), and Kendrick mass defect (KMD) analysis─referred to as TG-PCA-KMD─to investigate molecular-scale structural changes and quantitatively assess the progression of thermo-oxidative degradation in glass fiber reinforced polypropylene (GF/PP). TG-TOFMS enables the simultaneous and sensitive detection of both structural changes due to thermo-oxidative degradation and compositional changes in the filler and matrix. PCA and KMD analysis are crucial for identifying specific ion series derived from the degraded PP matrix in the high-resolution mass spectra obtained through TG-TOFMS. Additionally, PCA fitting was employed to selectively extract information on the degraded components of GF/PP from differential thermogravimetric profiles. Our findings demonstrate the advantages and utility of TG-PCA-KMD in the degradation analysis of composite materials.

Factors Influencing the Bond Strength between FRP Bars and Concrete and the Calculation Methods for Anchorage Length

Since the 21st century, developed countries such as Japan, the United States, and Europe have designated Fiber Reinforced Polymer (FRP) as a key industry for development. Currently, FRP sheets, represented by carbon fiber fabric, have become an important material for structural reinforcement and are widely used in the renovation and reinforcement of various civil and industrial buildings. For example, in the early 1960s, the American company Marshall-Vega produced Glass Fiber Reinforced Polymer (GFRP) bars to address the issue of salt corrosion in reinforced concrete structures in coastal and cold regions. In the design of the ArtScience Museum in Singapore, to ensure the integrity and smoothness of the architectural form, facilitate prefabrication and assembly of components, and meet structural, fire safety, and security requirements, the designers evaluated various materials and ultimately selected polyethylene resin-based GFRP panels. This paper employs a literature review methodology, first analyzing the factors that affect the bond strength between FRP bars and concrete, then reviewing standards to understand the calculation methods for anchorage length in different countries, collecting relevant experimental data, and finally analyzing the advantages and disadvantages of various anchorage length calculation methods.

Analysis Method of 131I Activity in Carbon Cartridge and Internal Dose Assessment for Nuclear Medicine Workers.

Inhalation of 131I is the main route for internal doses to nuclear medicine workers. This study aimed to establish a simple analysis method for determining 131I activity in carbon cartridges, explore the activity concentration of 131I in nuclear medicine departments, and evaluate the internal dose of workers. A total of 21 nuclear medicine departments in the hospital conducted air sampling using a high-volume air sampler equipped with carbon cartridges and glass fiber filters to collect gaseous 131I and aerosol 131I, respectively. Furthermore, a mathematical model was developed to analyze the 131I activity with inhomogeneous distribution in cartridges. Based on the 131I activity measured by the HPGe γ spectrometer, the personal annual inhalation effective dose was estimated. The results showed that there is a significant difference in the activity of gaseous 131I and aerosol 131I, with the activity ranging from 1.5±0.08 Bq m-1 to 3,944.23±197.21 Bq m-3 and ND (not detectable) to 842.11±42.11 Bq m-3, respectively. The activity of aerosol 131I is about 1% to 7% of that of gaseous 131I. The annual committed effective dose caused by inhalation of 131I for workers is 3.6 μSv to 8.23 mSv, which is lower than the dose limit of 20 mSv y-1. In general, the 131I contamination in the nuclear medicine department cannot be ignored, and the concentration of 131I should be regularly monitored to prevent and control the internal radiation to which workers may be exposed.

An Experimental Research Into the Bonding Strength of GFRP Bars in Concrete Under Elevated Temperatures

This study investigates the bond strength of Glass Fiber Reinforced Polymer (GFRP) bars in concrete at high temperatures. Twenty-four specimens were tested at 600°C to replicate fire conditions and analyze performance consequences in structural applications, with variables such as bar diameter and position within the concrete taken into account. The results show a considerable drop in binding strength, notably in edge-positioned bars with thinner covers, which is related to thermal degradation of the epoxy resin. The stress-slip relationship revealed significant increases in slippage, particularly for bigger diameter bars, as well as the vulnerability of GFRP bars to high temperatures. Failure modes shifted mostly to splitting following exposure, emphasizing the importance of design concerns in fire-prone structures. These findings improve our understanding of GFRP performance in harsh situations, influencing material selection for greater fire resilience.

Fracture resistance and behavior of endodontically treated maxillary premolars with varying ferrule heights and post numbers: A laboratory study.

To investigate how varying ferrule heights and the number of glass fiber posts affect fracture resistance and behavior of endodontically treated maxillary first premolars with substantial loss of tooth structure. Twenty-four extracted endodontically treated human maxillary first premolars were divided into three groups (n=8) based on ferrule height and post number. The groups were as follows: premolars of 2mm ferrule height that were restored with single posts (control group), premolars of 0.5mm ferrule height that were restored with single posts in palatal canals (single-post group), and premolars of 0.5mm ferrule height that were restored with double posts in palatal and buccal canals (double-post group). All groups were then restored with composite core and metal-ceramic crowns cemented with zinc phosphate cement. All specimens were subjected to 10,000 thermal cycles at temperatures of 5°C and 55°C, as well as 1.2 million cyclic loadings of 49N load at 1.2Hz using a chewing simulator. The specimens were loaded to fracture in a universal testing machine and fracture behavior was examined under stereomicroscope and divided into restorable and unrestorable fracture modes. Fracture loads and modes were analyzed by one-way ANOVA, Tukey's post hoc test, and Fisher's exact probability test (p≤0.05). The control group showed the highest mean fracture load (1127±172) of all groups (p<0.001). The specimens in the single-post group showed numerically higher mean fracture load (522±171) but with no significant difference compared to the ones in the double-post group (518±157; p>0.967). In the control group, 75% of specimens showed unrestorable fractures compared to 50% and 12.5% in single-post and double-post groups. The specimens in the control group had similar unrestorable fractures, starting from the coronal part and extending obliquely to the cervical third of the root below resin level. Two specimens in the control group showed unrestorable fractures in the middle third of the root. No middle-third root fractures were observed in single-post and double-post groups, and unrestorable fractures in both groups were similar to those of the control group. The single-post group had two specimens with core-post crown complex restorable fractures, while the control and double-post groups had one specimen each. The remaining specimens showed cervical-third root restorable fractures above resin level. The ferrule height significantly influences the fracture resistance of endodontically treated premolars compared to the number of placed posts. Nonetheless, more restorable fractures are seen in endodontically treated premolars restored with double posts than single posts regardless of ferrule height.

Study on Cut‐Resistance Properties of Composite Yarn Based Knitted UHMWPE Textiles: Influence of Reinforcement, Radiant Heat Exposure, Outdoor Environment, and Cutting Angles

ABSTRACTThe safety of workers in hazardous environments depends on personal protective clothing capable of withstanding various real‐world challenges, especially in automotive, glass, aerospace, mining, construction, and food industries where cut hazards are prevalent. Ultra‐high‐molecular‐weight‐polyethylene (UHMWPE) is widely utilized in cut‐protective textiles for its exceptional strength and durability. This study investigates the cut‐performance of stainless‐steel and glass fibers reinforced UHMWPE knitted fabrics under real‐world industrial conditions, focusing on the influence of varying cutting angles, outdoor environments, and thermal exposure on their cut‐protective efficacy. Reinforcement significantly improved cut‐performance, with stainless‐steel reinforced UHMWPE fabric (13SU) exhibited the highest tear strength (lengthwise‐313.1 N, widthwise‐405.8 N) and abrasion resistance (withstanding up to 800 rubbing cycles), providing best cut‐protection with cutting force of 32.43 N at 90° cutting angle. Differential scanning calorimetry (DSC) and scanning electron microscope (SEM) characterizations revealed UHMWPE's sensitivity to thermal effects, with a significant decrease in crystallinity after exposure to radiant heat flux of 20 kW/m2 at fabric surface, leading to diminished cut‐performance. Environmental durability assessments indicated a reduction in cut‐resistance properties due to changes in the chemical composition of UHMWPE polymer structure, such as the presence of ketone (CO) and hydroxy (OH) polar groups, as confirmed by Fourier‐transform infrared (FTIR) spectroscopy.

Mechanical Properties and Numerical Modelling for Prosthetic Foot

This study uses laminated composite materials made of hybrid glass and carbon fibers to determine the mechanical characteristics of the foot. Tensile, bending, and fatigue of composite material were evaluated and applied to the ANSYS model. The volume fraction for carbon and glass fibers was 22.5% and 10.04%, respectively. The mechanical property results: σy = 40 MPa, σult = 150 MPa, and E = 1.2 GPa. The patient is a 30-year-old male with a left amputation side, 1.60 meters tall, and weighs 74 kg. The analysis was carried out for the two scenarios (toe-off and heel contact) as boundary conditions. The overall deformation, equivalent stresses, and foot safety factor have been calculated using ANSYS17.2 software. In the end, it appears that the foot is secure based on equivalent stress calculations and the Von-Mises hypothesis. The computed safety factor for the foot is constructed of a chosen composite material with the subsequent layers. When the heel (stance phase) is fixed at 1.3449, and the metatarsal (toe off) is fixed at 1.259, the safety factor for a force of 860 N is reached. The foot is secure, according to the Von-Mises hypothesis.

Tough and circular glass fiber composites via a tailored dynamic boronic ester interface.

Glass fiber reinforced polymer (GFRP) composites are valued for their strength and cost-effectiveness. However, traditional GFRPs often face challenges for end-of-life recycling due to their non-depolymerizable thermoset matrices, and long-term performance due to inadequate interfacial adhesion, which can lead to fiber-matrix delamination. Here, we have designed dynamic fiber-matrix interfaces to allow tough and closed-loop recyclable GFRPs by utilizing a vitrimer, derived from upcycled polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) with boronic ester (S-Bpin) and amine-based diol crosslinker. The boronic ester groups in S-Bpin form dynamic covalent bonds with the naturally present hydroxyl groups on the unsized GF surface, which eliminates the need for fiber sizing and enables facile closed-loop recyclability of both the fibers and the vitrimer matrix. The resulting strong fiber-matrix interface, depicted by the Raman mapping, leads to a 552% increase in-plane shear toughness (6.2 ± 0.3 MJ m-3) and 27% ultimate tensile strength (361 ± 89.2 MPa) compared to those of the conventional epoxy-based matrix (0.95 ± 0.05 MJ m-3 and 264 ± 59.7 MPa, respectively). The network rearrangement through dynamic boronic ester exchange enables fast thermoformability and repairability of micro-cracks at elevated temperatures. Additionally, both the matrix and composite demonstrate strong adhesion to various surfaces including steel and glasses exhibiting ≥6 MPa lap shear strength, which expands their suitability for diverse industrial applications. The readily created dynamic interface between boronic ester functionalized vitrimer and neat GFs presents a promising strategy for developing closed-loop recyclable, multifunctional structural materials, offering a sustainable alternative to non-recyclable thermoset GFRPs and contributes to a circular economy in composite materials.

Impact of fibre reinforcement on cryogenic performance of novel epoxy composites for cryogenic applications

Due to the dynamic development of technology and science, there is an increasing demand for materials combining high mechanical resistance to extreme temperature conditions and suitable thermal properties. Especially the knowledge of heat transfers by conduction and thermal radiation is crucial for the successful design of devices operating at cryogenic temperatures, such as Dewars, cryostats, or space probes. This study aimed to assess important thermal and mechanical properties at cryogenic temperatures for three composite materials made of identical epoxy resin reinforced by carbon, basalt or glass fibres. Apart from loading/unloading cyclic tensile tests conducted at room temperature and in cryogenic environments at 77 K, thermal conductivity and total hemispherical emissivity were obtained in wide temperature ranges from 5 K up to 300 K. The results highlighted the importance of the fibre material and have potential to help with optimal material selection. We found that the initial stiffness of the laminates increased at low temperatures, and the glass composite exhibited the best mechanical properties. On the other hand, the carbon composite showed the lowest but steeply increasing thermal conductivity with increasing temperature. This, together with the lowest emissivity, makes the carbon composite a more favourable option for the lowest temperatures.

Mechanical Behavior and Microscopic Mechanisms of Glass Fiber–Modified Loess in Seasonally Frozen Regions

Mechanical Behavior and Microscopic Mechanisms of Glass Fiber–Modified Loess in Seasonally Frozen Regions

Confinement of Concrete Cylinders Using Dry Glass Fiber Hoops: Experimental Investigation and Analytical Modeling

Confinement of Concrete Cylinders Using Dry Glass Fiber Hoops: Experimental Investigation and Analytical Modeling