Composite Reinforcement Research Articles

Experimental study on the composite reinforcement method for single-column piers in existing bridges

Steel–concrete composite reinforcement technology has developed rapidly in recent years. This method has emerged as one of the best reinforcement alternatives in bustling sections because it saves time and space. In this paper, a combination reinforcement plan for single-column piers in curved bridges is proposed, with its interface performance being comprehensively investigated. Nine sets of comparative experiments were conducted to analyze the key issue of shear resistance at the interface between new and old concrete in the combination reinforcement scheme. It was found that under the proposed circumferential reinforcement structure, the stress changed from interface shear to overall compression; therefore, both ductility and the failure bearing capacity were improved owing to the Poisson effect in the later stage of the interface treatment component. Meanwhile, using the calculation formulas in existing reinforcement specifications, we introduce the shear strength parameters under a new "serrated groove" situation, which has higher bearing capacity than the commonly used chiseling and groove modes. The methodology and findings of this study supplement the single-column pier combination reinforcement for existing bridges in urban sections and lays the foundation for future research.

Interfacial reinforcement of aramid composites through amino SiO2 interphase for ballistic application

Interfacial reinforcement of aramid composites through amino SiO₂ interphase for ballistic application

Numerical Analysis of Laminated Veneer Lumber Beams Strengthened with Various Carbon Composites.

Among the many benefits of implementing numerical analysis on real objects, economic and environmental considerations are likely the most important ones. Nonetheless, it is also crucial to constrain the duration and space necessary for conducting experimental investigations. Although these benefits are clear, the applicability of such models must be appropriately verified. This research subjected validation of numerical models depicting the behavior of unstrengthened and strengthened laminated veneer lumber (LVL) beams. As a reinforcement, a carbon fiber reinforced polymer (CFRP) sheet and laminates were used. Experiments were conducted on full-scale members within the framework of the so-called four-point bending testing method. Numerical simulations were performed using the Abaqus software. Two types of material models were examined for laminated veneer lumber: linearly elastic and linearly elastic-perfectly plastic with Hill's yield criterion. A distinction was made in the material properties of carbon composites based on their location on the height of the cross-section. The outlined numerical models accurately depict the behavior of real structural elements. The precision of predicting load-bearing capacity amounts to a few percent for strengthened beams and a maximum of eleven percent for unstrengthened beams. The relative deviation between numerical and experimental values of bending stiffness was at a maximum of seven percent. Applying the elastic-plastic model enables accurate representation of the load versus deflection relation and the distribution of stress and deformation of strengthened beams. Based on the findings, directives were provided for further optimization of the positioning of composite reinforcement along the span of the beam. Reinforcement design of existing laminated veneer lumber members can be made using presented methodology.

Thermo-mechanical performance characteristics of glass reinforced HDPE composites: A comprehensive review

Millions of tonnes of plastic and glass waste is produced worldwide, with only a limited quantity being recycled with the majority ending up in landfill, our oceans or in stockpiles. Even though current applications exist for recycled glass and plastic, there is still a need to introduce recyclate to different industries. This review presents an investigation aimed at mechanical and thermal property improvements by the incorporation of reinforcement material into a polymeric matrix. The performance of high-density polyethylene (HDPE) and glass composites manufactured with different levels of glass, additives and surface treatments have been evaluated by analysing several past investigations. The critical parameters influencing the mechanical and thermal performance of HDPE-Glass composites were identified to be the type of reinforcement, glass content, additives utilised, and the different manufacturing methods employed. Optimised mix designs proposed by researchers have been analysed along with reaction mechanisms. This review has identified a composite material to be further refined and optimised with the potential to be improved by integrating reclaimed waste to manufacture composites by promoting a zero-waste economy. Improvements in tensile strength up to 71% can be observed with the implementation of 20% by weight of glass reinforcement in HDPE composites. The use of maleic anhydride grafted polyethylene (MAgPE) as a compatibilizer facilitates the stress transfer between the two phases by improving their bonding with tensile and flexural strength increments up to 85% and 25%, respectively. This review is a valuable resource for future researchers as it identifies crucial research gaps in HDPE-Glass composite manufacturing and synthesises key findings in existing literature.

Assessing the consequences of water retention on the structural integrity of jute fiber and its composites: A review

AbstractResearchers have compared natural jute fiber to synthetic fibers due to their distinct physical and mechanical properties, which have been recognized for decades. Jute fibers are a very versatile type of vegetable fibers widely used in structural composites and it has also shown potential in various applications such as nanoparticles, building interior, and automotive components. However, designing jute composite parts is a challenging task due to plant origin, growth conditions, age, stem location, extraction method, and non‐uniform fiber cross section. The current review aims to provide a comprehensive analysis of the existing literature on jute fiber and its composites of water and moisture absorption behavior on their performance. The most relevant findings regarding jute fiber water and moisture absorption characteristics have been summarized and analyzed in this review paper. In addition, this article presents an overview of the main characteristics of jute fibers, several parameters influencing the characteristics of jute fibers, jute fiber reinforcement composites, impact of relative humidity, swelling properties on jute fiber composite materials, and potential future research areas are also highlighted.Highlights Higher growing interest of researchers for jute fiber Factors affecting the properties of jute fibers Various way of making jute fiber reinforced composites Influence of moisture on its properties Present and future areas of its upgradation

Characterization of natural cellulosic fiber extracted from Grewia ferruginea plant stem

The use of natural fibers as reinforcement in polymer composites has gained significant attention due to their eco-friendly, and biodegradability. This study aims to extract and characterize the natural cellulosic fibers from the Grewia ferruginea stem. The fibers were extracted from plant stems using sodium hydroxide and analyzed using Fourier Transform infrared spectroscopy (FTIR) to determine chemical bonds on the fiber and functional group and Thermos-gravimetric analysis (TGA) was used to determine the thermal stability and degradation temperature of the fiber. The crystalline properties of extracted fibers were characterized by x-ray diffraction and surface morphology was characterized by Scanning electron microscopy. The chemical composition of the fibers, including cellulose, hemicellulose, lignin, moisture, extractive content, and fiber linear density, was evaluated. Tensile, thermal, and FTIR studies were conducted to assess the performance properties of the extracted fiber. The analysis revealed that the Grewia ferruginea fibers contain cellulose (60.4–72.6 wt%), hemicellulose (18.5 ± 3.1 %), and lignin (13.55 ± 2.75 %). The extracted fibers have a crystallinity index of 48.76 % and crystallite size of 5.14 nm. The fiber exhibited tenacity, breaking elongation, and Young's modulus values of (52.3 ± 6.5 cN/tex), (3.6 ± 1.8 %), and 43.5 ± 2.3 GPa, respectively. FTIR studies confirmed the presence of biopolymers in the Grewia ferruginea fiber. Additionally, the fibers demonstrated thermal stability up to 275 °C based on thermogravimetric analysis. These findings suggest that the extracted natural cellulosic Grewia ferruginea fiber has the potential to be used as a sustainable reinforcement material in polymeric composites.

Parameters identification and application of composite plate reinforcement mesh based on DXF data

Abstract This paper presents an algorithm for identifying the process parameters of a laminated plate reinforcement mesh. To accommodate the actual production needs, the computer software of the production line is employed for the identification of parameters and data processing of the DXF steel mesh file. In this context, a C++ programming algorithm is utilized for the identification of the parameters of the imported DXF file, as per the production line’s processing requirements. DXF is an AutoCAD vector graphics exchange file that is available in two storage formats: ASCII format and binary format. The ASCII format is easily readable and therefore, DXF is widely used, with most CAD software capable of reading or outputting DXF files. This paper initially scrutinizes the structural attributes of DXF files, normalizes the design standard of graphics files, and then reads the coordinates of each point of the POLYLINE entity. A parameter identification algorithm is devised to address the issue of steel bar bending in drawings, with the program designed to verify its accuracy.

A Concise Review of the Components and Properties of Wood-Plastic Composites.

This article summarizes findings in the field of the history, composition, and mechanical properties of WPCs (wood-plastic composites) formed by combining two homogeneous substances, i.e., a polymer matrix with cellulose fibers in a certain ratio (with the addition of additives). In relation to a wide range of applied natural reinforcements in composites, it focuses on wood as a fundamental representative of lignocellulosic fibers. It elucidates the concept of wood flour, the criteria for its selection, methods of storage, morphological characteristics, and similar aspects. The presence of wood in the plastic matrix reduces the material cost while increasing the stiffness. Matrix selection is influenced by the processing temperature (Tmax = 200 °C) due to the susceptibility of cellulose fibers to thermal degradation. Thermoplastics and selected biodegradable polymers can be applied as matrices. The article also includes information on applied additives such as coupling agents, lubricants, biocides, UV stabilizers, pigments, etc., and the mechanical/utility properties of WPC materials. The most common application of WPCs is in automotive sector, construction, aerospace, and structural applications. The potential biodegradability and lower cost of applications featuring composite materials with natural reinforcements motivated us to delve into this type of work.

Influence of alkali treatment on thermal stability of polyester composites reinforced with Bambusa maculat fibers

The various species of bamboo plants cultivated in Indonesian people's plantations are apus bamboo (Gigantochloa apus) (GA), wulung bamboo (Gigantochloa atroviolacea) (GV), and tutul bamboo (Bambusa maculat) (BM). Apart from being used as a craft material and household utensils, bamboo can be made into natural fiber as a reinforcement for polyester composites. In this research, Bambusa maculat fiber was used. In this work, BM fibers were treated with Alkali with NaOH solutions with concentrations of 2, 5, and 8% by weight respectively at room temperature. The next procedure is that the BM fibers are used as composite reinforcing fibers, arranged unidirectional the polyester composites. The manufacturing technique is using hot pressing molding technique. The effect of alkali concentration on the thermal performance of polyester composites was examined using differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. As the result, the alkaline treatment of BM bamboo fiber with a NaOH concentration of 5%, causes the BM bamboo fiber as reinforcement and matrix to have a tight interface and strong interfacial bonding, allowing the composite to have the best thermal stability among other composites.

Advancing infrastructure resilience: A polymeric composite reinforcement grid with self-sensing and self-heating capabilities

In this study, a novel multifunctional grid-shaped polymeric composite (MGPC) with reinforcing, autonomous strain, stress, and damage sensing and localizing in addition to targeted heating capabilities, has been developed. Distinct from preceding composites, this grid synthesizes these features collectively for the first time and concurrently addresses current challenges in multifunctional composites, such as environmental impact, data reliability, complexity, and production costs. The fabrication process entails 3D printing an electrical circuit with conductive filaments within a polylactic acid (PLA) host polymer. The conductive filament was composed of a thermoplastic polymer (TPU) infused with carbon nanotubes (CNT)-grafted carbon fibres (CFs) produced via chemical vapour deposition. The mechanical, microstructural, and electrical properties of the grid elements and cementitious slabs reinforced with MGPC were comprehensively examined. The MGPC's performance in traffic flow monitoring, mechanical behaviour prediction, and damage localization was assessed through wheel tracking, asymmetric punch tests, piezoresistivity response evaluation, and digital image correlation techniques. Furthermore, the self-warming ability of the MGPC in cementitious composites was investigated using different voltages. The extruded TPU containing CNT-grafted CFs exhibited an electrical percolation threshold of approximately 5.0 wt%, resulting in a conductivity of around 70 S/m for the filaments. Incorporating MGPC as reinforcement within cementitious composite slabs led to notable enhancements, with flexural strength increasing by approximately 15 % and failure strain by up to 350 %. Wheel tracking tests revealed changes in the electrical: 5.8 % for 520 N and 7.8 % for 700 N wheel loads, with roughly 5.0 % average error in velocity detection. Transverse elements precisely detected wheel locations demonstrating the MGPC capabilities in accurately detecting wheel speed weight, and location. The study established strong correlations between electrical resistance changes, mechanical behaviour, and damage detection, affirming the MGPC's reliability and efficacy for damage monitoring and localization. The cementitious slab reinforced with MGPC reached around 52°C through a 20 V direct current, with a heating rate of 0.25°C/s and a power density of 142 W/m², showing its potential for practical applications such as self-healing and de-icing. However, design parameters such as mesh and conductive circuit configuration, long-term performance, as well as Life Cycle Assessment need further investigation.

Improvement of physical, chemical, mechanical, and morphological properties of Luffa cylindrica fiber reinforcement composites using Java seed filler

Improvement of physical, chemical, mechanical, and morphological properties of Luffa cylindrica fiber reinforcement composites using Java seed filler

Design Potential of Technical Hemp and PLA Nonwovens

ABSTRACT The main purpose of the article is to present the potential use of hemp fibers as reinforcement in composites, but from a design perspective. The authors ask whether sustainable nonwovens, produced based on natural fibers, have the potential as a material for designers and artists and not only as a technical textile. Technical production of nonwovens like carding, punching and laser cutting was used to achieve not just functional, but also aesthetic quality of the samples. The possibilities of utilizing natural materials for design endeavors were presented. The production process of these items was described, along with the main design concept. Research was carried out through a series of interdisciplinary activities, using the knowledge and tools typical for textile and materials engineering, as well as the methodology and strategies derived from the fields of visual art and design. It has been shown that during the development of a new sustainable material significant attention should be paid to design aspects, so it shows its full potential, as not just being eco-friendly, but also functional and aesthetic. While technical hemp and PLA composites have been produced and studied before, the design aspect is unique in the current study.

Fiber reinforcement of calcium silicate hydrate-based contact-hardening composites induced by compression

Calcium silicate hydrate in amorphous nature can be used to prepare water-resistant artificial blocks by direct compression at room temperature. These blocks have light weight and high strength, but their relatively high brittleness limited its utilization as construction materials. The purpose of this study is to improve the toughness of calcium silicate hydrate-based blocks by adding polypropylene fiber and emulsion in the powder before compressing. The effect of fiber and emulsion content on the density, strength and toughness of the hardened composite materials was explored. Microstructure of the fracture surface was evaluated through SEM. Result showed that the flexural strength of the hardened composite material increased significantly with the increase of the fiber content, while its compressive strength showed a downward trend. When the fiber content was 3%, the flexural strength and flexural toughness was 250% and 30.6% higher than those of the plain specimen, respectively. C-S-H powder particles adhering to the surface of the fiber increased the adhesion force between the fiber and C-S-H compact matrix, helping to improve the friction resistance when the fiber was pulled out, and thus the strength was increased. Adding 2% emulsion showed negative effect on the strength of the hardened composite, but could improve its toughness and machinability, acting as a wood-like material.

Optimization of fibre orientation for composite reinforcement of circular hollow section KT-joints

PurposeComposite materials are effective alternatives for rehabilitating critical members of offshore platforms, bridges, and other structures. The structural response of composite reinforcement greatly depends on the orientation of fibres in the composite material. Joints are the most critical part of tubular structures. Various existing studies have identified optimal reinforcement orientations for a single load component, but none has addressed the combined load case, even though most practical loads are multiplanar.Design/methodology/approachThis study investigates the optimal orientation of composite reinforcement for reducing stress concentration factors (SCF) of tubular KT-joints. The joint reinforcement was modelled and simulated using ANSYS. A parametric study was carried out to determine the effect of the orientations of reinforcement in the interface region on SCF at every 15° offset along the weld toe using linear extrapolation of principal stresses. The impact of orientation for uniplanar and multiplanar loads was investigated, and a general result about optimum orientation was inferred.FindingsIt was found that the maximum decrease of SCF is achieved by orienting the fibres of composite reinforcement along the maximum SCF. Notably, the optimal direction for any load configuration was consistently orthogonal to the weld toe of the chord-brace interface. As such, unidirectional composites wrapped around the brace axis, covering both sides of the brace-chord interface, are most effective for SCF reduction.Originality/valueThe findings of this study are crucial for adequate reinforcement of tubular joints using composites, offering a broader and universally applicable optimum orientation that transcends specific joint and load configuration.

Non-covalent interaction induces controlled reinforcement of thermoplastic elastomer composites homologously incorporated with hydrophobized cellulose nanocrystals

Surface hydrophobization of cellulose nanocrystal (CNC) is developed through Pickering emulsion method and esterification-grafting, consequentially enhancing its thermal properties and hydrophobicity, and tensile modulus in thermoplastic elastomer composites. n-Tetradecenylsuccinic anhydride (TDSA) provides a high level of compatibility owing to the structural homology by non-covalent interactions between CNC-graft-TDSA and poly(styrene)-block-poly(isoprene)-block-poly(styrene) (SIS). Theoretical calculations supports the molecular-level insight on how the nanofiller and SIS interacts. Density functional theory calculations and the energy decomposition analysis reveal the stabilization free energy of −2.59 kcal mol−1 gained through hydrophobic and OH–π interactions, which is assigned as the key component for the superior mechanical properties. At the filler contents of 0.6–2.5 vol %, the moduli of the TPE nanocomposites gradually strengthen while retaining thermoplasticity, without sacrificing the ultimate tensile characteristics of SIS, although it is below the calculated φc of 5.9 vol % (critical percolation threshold) for filler-filler interactions. Origin of the controlled boost in filler-matrix binding is rationalized by pronounced hydrophobic interactions in isoprene-rich rubbery phase (86 wt % in SIS). Interestingly, at 5.1 vol % near to filler-filler interactions, even though reinforcements in storage/initial modulus, and toughness increase by up to 14/4.0-, and 1.2-fold, the tensile stress at break only decreases by 27 %.

Microcrystalline Cellulose as Composite Reinforcement: Assessment and Future Prospects

In order to enhance diverse composites and foster sustainable development, it is essential to use strategic measures. Microcrystalline cellulose (MCC) has the desirable characteristics of being both renewable and biodegradable. The characteristics above provide MCC with a favorable option for enhancing the structural integrity of composite materials. This study examines the literature on using MCC as a composite reinforcement to identify its primary characteristics. This evaluation explores the properties and potential future advancements of the naturally derived materials under investigation. This work comprehensively reviews scientific publications to guide future research efforts. Based on empirical investigations, using MCC as a composite reinforcement has enhanced various mechanical and tribological characteristics. This study provides a comprehensive reference for implementing sustainable MCC as a composite reinforcement.

The Effect of Bleaching Variation on Schoutenia Ovata Korth Fiber as a Composite Reinforcement

The study examined the properties of bleached Schoutenia ovata Korth Fiber (SF) for prospective application in composite reinforcement. .The characterization of SF was done using FTIR and SEM-EDS techniques to examine the morphology of SF following treatment with NaOH and various concentrations of NaClO. The treatment improved the interaction between the fiber and the composite matrix. As a result, fibers require bleaching before they may be processed further.

Experimental evaluation of mechanical characteristics of concrete composites reinforced with jute fibers using bricks waste as alternate material for aggregates

In order to achieve high strength in concrete composites, various fiber reinforcements in plain concrete composites (PCC) are used. Steel is widely used for this purpose but the main issue in using steel as a reinforcement member is rusting, which results into structure deterioration. So, the alternative is to use a durable, environment friendly, and cost-effective natural fiber. Jute Fiber is used in this study for the reinforcement of plain concrete composites while, the plain concrete composites were made with cement, sand, and bricks waste. The comparative study of using bricks waste as an alternative material to crush bricks is also presented in this research study. Bricks waste and its disposal is becoming an environmental challenge. This study proposes jute fibers as a reinforcement element and uses bricks waste as an alternative material to crushed stone. M20 grade concrete with various volumetric percentages (0.05%, 0.10%, 0.25%, 0.50%, and 1.00%) of 10 mm long jute fibers are produced. An increase of 39% and 37% in compressive strength and split tensile strength, respectively, was observed after the addition of jute fibers. Therefore, the use of jute fibers and bricks waste to replace crushed stone is an effective way to mitigate environmental pollution and sustainability issues.

Investigation of Carbon Fiber Reinforced Polymer Concrete Reinforcement Ageing Using Microwave Infrared Thermography Method

This study presents the utilization of the microwave infrared thermography (MIRT) technique to identify and analyze the defects in the carbon-fiber-reinforced polymer (CFRP) composite reinforcement of concrete specimens. At first, a set of numerical models was created, comprising the broadband pyramidal horn antenna and the analyzed specimen. The utilization of the system operating at a power of 1000 W in a continuous mode, operating at frequency of 2.45 GHz, was analyzed. The specimen under examination comprised a compact concrete slab that was covered with an adhesive layer and, thereafter, topped with a layer of CFRP. An air gap represented a defect at the interface between the concrete and the CFRP within the adhesive layer. In the modeling stage, the study investigated three separate scenarios—a sample with no defects, a sample with a defect located at the center, and a sample with a numerous additional random defects located at the rim of the CFRP matte—to analyze the effect of the natural reinforcement degradation in this area. The next phase of the study involved conducting experiments to confirm the results obtained from numerical modeling. In the experiments, the concrete sample aged for 10 years with the defect in the center and naturally developed defects at the CFRP rim was used. The study employed numerical modeling to explore the phenomenon of microwave heating in complex structures. The aim was to assess the chosen antenna design and identify the most effective experimental setup. These conclusions were subsequently confirmed through experimentation. The observations made during the heating process were particularly remarkable since they deviated from earlier studies that solely conducted measurements of the sample post-heating phase. The findings demonstrate that MIRT has the capacity to be employed as a technique for detecting flaws in concrete structures reinforced with CFRP.

A Review of Sisal Fiber-Reinforced Geopolymers: Preparation, Microstructure, and Mechanical Properties.

The early strength of geopolymers (GPs) and their composites is higher, and the hardening speed is faster than that of ordinary cementitious materials. Due to their wide source of raw materials, low energy consumption in the production process, and lower emissions of pollutants, they are considered to have the most potential to replace ordinary Portland cement. However, similar to other inorganic materials, the GPs themselves have weak flexural and tensile strength and are sensitive to micro-cracks. Improving the toughness of GP materials can be achieved by adding an appropriate amount of fiber materials into the matrix. The use of discrete staple fibers shows great potential in improving the toughness of GPs. Sisal is a natural fiber that is reproducible and easy to obtain. Due to its good mechanical properties, low cost, and low carbon energy usage, sisal fiber (SF) is a GP composite reinforcement with potential development. In this paper, the research progress on the effect of SF on the properties of GP composites in recent decades is reviewed. It mainly includes the chemical composition and physical properties of SFs, the preparation technology of sisal-reinforced geopolymers (SFRGs), the microstructure analysis of the interface of SFs and the GP matrix, and the macroscopic mechanical properties of SFRGs. The properties of SFs make them have good bonding properties with the GP matrix. The addition of SFs can improve the flexural strength and tensile strength of GP composites, and SFRGs have good engineering application prospects.