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In our investigation, we subjected eleven reinforced concrete beams to a four-point bending system to explore the impact of varying fibre and ferrocement contents on their structural behaviour. These beams, measuring 1.7 m in length, featured a rectangular cross-section with dimensions of 150 mm by 300 mm. Our study focused on three key variables: steel fibre content (at levels of 0.5%, 1%, and 1.5%), glass fibre content (also at 0.5%, 1%, and 1.5%), and ferrocement content (evaluated with one or two layers of welded or expanded wire mesh). Our findings revealed that incorporating fibres with minimal shear reinforcement significantly enhanced the beams' performance. Specifically: The specimen reinforced with 1.5% steel fibres exhibited the highest ultimate failure load, surpassing the control beam by an impressive 41.87%. The 0.5% glass fibre specimen experienced the least deflection at the ultimate load compared to the control beam. The 1.5% glass fibre specimen demonstrated superior energy absorption compared to the control specimen. Notably, using two layers of welded wire mesh proved most effective in enhancing the ultimate failure load when compared to both the control specimen and other ferrocement-strengthened beams. [ABSTRACT FROM AUTHOR]

In this paper, the authors have presented extensive work done involving the design, simulation, development, and performance measurement of a novel Glass Fiber Reinforced Polymer (GFRP) composite-based metasurface patch antenna. The authors have first designed GFRP composite-based metasurface patch antenna and simulated the design to measure its performance. Then the same antenna has been indigenously developed following the design specifications. Using the developed antenna, measurements have been recorded and performance has been analysed. Moreover, considering the significance of benchmarking, the authors have also compared the performance of the design and developed GFRP composite-based metasurface patch antenna results against the performance of Linear C-band patch antenna and a GFRP-based metasurface patch antenna. The results obtained through simulation and testing show characteristic similarity thus validating the approach adopted for the printing of copper on GFRP composite. The results also show that using GFRP composite as a metasurface on top of simple microstrip patch antenna results in an overall 39% gain enhancement compared to simple microstrip patch antenna gain.

Six (1000*1000 mm2) slab specimens were cast and tested as two-way simply supported slabs previously (three under monotonic loading and three under repeated loading) are used in this research. The tested specimens consist of one solid slab and two voided slabs with the following variables (type of slab (solid and voided), presence of steel fibers (0% and 1%), and the presence of GFRP layers). This paper presents the results of tested slabs and the 3D-Nonlinear finite element (ABAQUS program) is proposed to verify the tested slabs under monotonic and repeated loading. The process of modeling the structure components of the tested slabs will be discussed in detail, including the creation of the parts, model material properties, surface interaction, loading method, boundary conditions, and meshing. Then, the experimental findings will be compared to the proposed FE models. A parametric study with new variables has been investigated that affect the behavior of reinforced concrete slabs and is not implemented in the experimental part of this study. These specimens are divided into two groups according to the nature of loading as in the experimental work. The created finite element models can accurately reflect the test results with an acceptable degree of difference in deflection and ultimate load by 10%. The crack patterns obtained using finite element models for the investigated specimens under monotonic and repeated loading are extremely similar to the crack patterns observed in the experimental work.

The behaviour of lightweight concrete (LWC) edge column-slab connections reinforced with two types of flexural reinforcement glass fiber-reinforced polymer (GFRP) and steel bars with different ratios of shear reinforcement are investigated experimentally and analytically using ABAQUS software. The experimental protocol covered evaluation of eight slabs and edge columns measuring subjected to static loading. Slabs are evaluated as supported, free-standing at one edge, and the column connection is included. The slabs are divided into two groupings, with four slabs in each group. The first group was reinforced with steel flexural, while the second group was reinforced with GFRP reinforcement. Within each group, one slab lacked shear reinforcement, while the other was reinforced with a varying shear reinforcement ratio. A good agreement was found between the numerical FE model and experimental outcomes in most tested slabs.

The objective of this study is to evaluate the mechanical behavior of GRFP in massive concrete slabs. The use of glass fiber reinforced polymer (GFRP) rebars in construction design has been an alternative technique to provide more durable structures. However, there is a need to evaluate the behavior of GFRP reinforced slabs under flexure and to compare the service state (SS) and ultimate service state (USS) of the loaded element. Thus, reinforced concrete slabs of varying thicknesses were constructed with steel and GFRP rebars. Results show that the applied load for maximum span deflection of the GFRP slab under SS was 50% lower than for the one with steel reinforcement. The maximum span deflection of the GFRP slab under USS was also 282% larger than for steel rebars reinforcement.

Hydraulic steel gates are commonly used for their superior characteristics in carrying both tensile and compressive stresses. Corrosion, operation, and maintenance costs make it essential to search for suitable alternatives. In this research, Glass Fiber Reinforced Polymers (GFRP) were investigated as a promising choice that can be used to resist flexure stresses as in case of hydraulic gates. Firstly, typical mechanical tests were conducted on nine specimens made of pure steel beams, four ribbed steel beams, twenty-four specimens of pure GFRP beams, along with four combined specimens from both materials. GFRP beams were also used in cooperation with polyester cemented sand to form a sandwich like beam. It was concluded that beams from GFRP achieved similar flexural capacity of steel beams of slimmer thickness. Combinations of steel and GFRP show satisfactory results while maintaining member ductility. The load capacity of the strengthened steel beams increased by 80% to 97% compared to specimens made from steel only. Failure modes for all specimens were introduced and compared. Moreover, numerical investigation was conducted using ABAQUS nonlinear module. Finite element models for three small gates of dimensions (1.0 x 1.0 m). A steel gate of thickness 14mm, Pure GFRP gates of thicknesses 29mm and 45mm were simulated. The 29mm GFRP gate was able to bear almost the same loads of the steel gate with equivalent deflection. Finally, it can be concluded that for small-scale hydraulic gates, GFRP can effectively be used as a suitable alternative for steel gates after setting limitations for failure strains.

This study evaluated the uniaxial tensile strength and bond performance of natural hybrid reinforcement bars. Hybrid FRP combines multiple fibers and matrixes, resulting in a desirable performance. Two types of hybrid bars were tested: one with natural fibers surrounded by glass fiber, and the other with a steel core surrounded by natural fiber and then glass fiber. Thirteen samples were used to assess tensile behavior, with four groups including glass fiber, flax, sisal, and jute fibers. Pull-out behavior testing was conducted on twelve samples, divided into four groups of fiberglass, flax, sisal, and jute. Each group used three types of concrete: normal, high strength, and ultra-high-performance concrete (UHPC). The results refer to flax samples that had a higher tensile strength and elastic modulus of 143 MPa and 38 GPa, respectively, than samples made of sisal and jute fibres. The hybrid bars with a steel core exhibited a significant improvement in elastic modulus of 206 % in compared to samples made solely from glass, sisal, and jute fibers. On the other hand, the samples with UHPC showed the highest bond strength. The sample U-GFRP with ultra-high-performance concrete showed the highest bond strength 9.32 MPa, while the sample N-GFRP with normal concrete showed the lowest bond strength 5.87 MPa, respectively. However, this study suggests that hybridizing natural fibers can be a cost-effective and eco-friendly alternative to synthetic fibers.

This paper experimentally investigated the monotonic and cyclic behaviour of one-way basalt and glass fibre-reinforced polymers (BFRP and GFRP) reinforced concrete (RC) slabs compared with that of traditional steel RC ones. A total of nine 2000×700×100 mm RC slabs, including three BFRP RC (BRC), three GFRP RC (GRC), and three steel RC (SRC) slabs, were tested. The results indicated that the behaviour of BRC and GRC slabs was governed by the elastic characteristic of FRP bars, resulting in a more uniform curvature of the slabs. The behaviour and failure modes of BRC and GRC slabs were comparable with those of SRC slabs. The similarity and difference were characterized by the rupture of FRP bars and the yielding of steel bars. Postcrack stiffness of BRC and GRC slabs was significantly lower than that of SRC slabs and was marginally affected by the effect of cyclic loading. The ultimate loads and ultimate deflections of BRC and GRC slabs were ∼2.0 and 1.6–2.0 times those of SRC slabs, respectively. Concepts of ductility, safety factor, and warning index were introduced and quantified for FRP RC slabs. BRC and GRC slabs had a significantly higher ductility (8.5–10.4) than SRC slabs (5.1–6.2), showing a highly ductile behaviour. SRC slabs had a safety factor of 1.0–1.1, while BRC and GRC slabs had a significantly higher safety factor of 3.8, showing their lower failure probability of BRC and GRC slabs when they are designed at a similar load as SRC slabs. The warning index of SRC slabs was 14.4–30.2, and that of BRC and GRC slabs was 65.1–71.6 and 63.9–86.0, respectively. The strength, ductility, safety factor, recovery, and warning index of BRC and GRC slabs were high, confirming their advanced characteristics. Under cyclic loading, BRC and GRC slabs have significantly larger stiffness degradations (4.4 %–7.2 %/cycle) than SRC slabs (1.62 %−3.2 %/cycle). The results of theoretical analyses showed that the strengths of BRC and GRC slabs can be reasonably predicted. The outcomes indicate the high potential use of FRP reinforcement for slabs in engineering practice.

The resin curing process triggered by ultraviolet radiation possesses numerous advantages, including rapid speed, low cost, and minimal environmental impact. Due to the hindrance of light propagation by the medium, uneven curing or incomplete curing at the bottom may occur frequently, particularly when the material thickness is excessive. To address these issues and delve into the regularities of the light‐curing process, this study employed a modeling approach that separately represents fiber bundles and the resin matrix to construct a mesoscopic model of the resin‐based glass fiber‐reinforced composite material glass fiber reinforced polymer (GFRP). Based on the models of light propagation, light‐curing kinetics, and heat conduction, a multiphysics field decoupling model is established to simulate the light‐curing process of GFRP. Using this model, the temporal and spatial variations of the internal light field, degree of curing field, and temperature field within GFRP during the curing process are simulated. The mechanistic reasons for these variations are analyzed. Finally, in conjunction with the regular analysis based on the macroscopic model, the accuracy of the model and the obtained regularities are validated through experiments. This provides an effective analytical method for the study of light‐curing in resin‐based fiber‐reinforced composite materials. [ABSTRACT FROM AUTHOR]

During the infusion process of a glass-fiber-reinforced thermosetting composite hose, the viscosity of its resin matrix undergoes temporal variations. Consequently, if the impact of resin viscosity changes over time on the internal resin fluidity is not considered during the infusion process, this may result in the incomplete impregnation of the hose, characterized by the presence of numerous voids. This phenomenon adversely affects the quality of the pipe's curing and forming process. Therefore, based on the characteristic variations in resin viscosity, this paper considers the changes in fluidity caused by the resin's temporal evolution within the material. We establish a finite element simulation model to calculate and analyze the overall infusion effects of resin viscosity changes during the hose infusion process. Furthermore, based on the predicted analysis, a variable parameter infusion strategy is proposed to increase resin impregnation in the hose, thereby reducing internal void content and subsequently improving the quality of material curing and forming. [ABSTRACT FROM AUTHOR]

Behavior of fiber‐reinforced polymer reinforcing bars – Experimental investigation of the stress distribution along the bond length Due to the non‐rusting properties of fiber‐reinforced polymer reinforcement (FRP), it is possible to position this reinforcement close to the surface in components without restricting its durability. In this case, the proportion of the concrete cover remains to ensure the bond. The normative minimum concrete cover is adapted to the bond behavior of reinforcing steel. As the geometry and material properties of FKB vary, their bond behavior is bar‐specific and cannot be equated with that of reinforcing steel. For this reason, the transferability of the minimum concrete cover defined for reinforcing steel to ensure the bond for FRCs must be questioned. To derive a minimum concrete cover, it is necessary to investigate the stress distribution along the bond length. The ring test was developed in the 1990s to experimentally determine the bond stress τ acting along the reinforcing bar and the radially acting internal pressure pi. This article aims at experimentally determining the stress distribution along the bond length for three different FKBs. For this purpose, the ring test is modified so that a (quasi‐)continuous measurement of the bond stress and the internal pressure along the bond length as a function of the pull‐out force is possible. As a result, the different stress distributions are compared and a minimum concrete cover to ensure the bond is derived from the internal pressure. [ABSTRACT FROM AUTHOR]

Hollow structures reduce weight without compromising load-bearing capacity and are widely used. The new Glass-Fiber-Reinforced Polymer high-strength thin-walled inner mold simplifies internal cavity construction and boosts structural performance. This study first investigates the influence of a GFRP high-strength thin-walled circular tube on the cross-sectional load-carrying capacity of hollow slabs. Then, a formula for the bending load-carrying capacity of the section under the action of the tube is derived. The results indicate that when the height of the concrete compression zone meets certain conditions, GFRP high-strength thin-walled circular tubes can improve the ultimate load-carrying capacity of the hollow floor slabs. In order to achieve a more economical design, the bending moment modification of a GFRP high-strength thin-walled circular tube of a continuous slab was studied. Research has found that the bending moment modulation limit for a continuous slab is 35.65% when it is subjected to a load of P u = 24   k N . Experimental analysis has shown that the results are generally consistent with the calculations. In practical engineering, the application of a GFRP high-strength thin-walled circular tube of continuous slabs has limitations. Therefore, this study investigated a GFRP high-strength thin-walled honeycomb core slab and found that its ultimate load-bearing capacity is greater compared to waffle slabs. In addition, the stress performance of the GFRP high-strength thin-walled honeycomb core internal mold is superior, making it more promising for practical applications. [ABSTRACT FROM AUTHOR]

This article explores the punching shear behavior of GFRP-RC interior slab–column connections. The parameters tested included the column–aspect ratio (1.0, 2.0, 3.0, 4.0, and 5.0), perimeter-to-depth ratio for square column stubs with side lengths of 0.3, 0.4, 0.5, 0.6, and 0.7 m, and span-to-depth ratios of 4, 6, 8, 10, and 12. A review of the literature revealed that no previous study has investigated the effect of these parameters or their interactions on this type of connection. Numerically, twenty-five slabs were created using finite element (FE) software (V3), each with square dimensions of 2.5 m and a constant thickness of 0.2 m. The central column extended 0.3 m from the top and bottom of the slab. All four sides of the slabs were supported, and the specimens underwent pure static shear load testing. The test results demonstrated that all slabs failed due to punching shear. Increasing any parameter value reduced the punching shear stresses. Additionally, the results indicated that Canadian (CSA-S806-12) and Japanese (JSCE-97) standards for FRP-RC materials generally provided the closest predictions of punching shear capacity compared to the American guideline, ACI 440.1R-22. However, all standards exhibited shortcomings and require enhancement and modifications, particularly to consider the impact of the span-to-depth ratio. Therefore, three equations were developed to predict the shear strength of the connections, yielding better results than those prescribed by the North American and Japanese standards. [ABSTRACT FROM AUTHOR]

The existence of a notch in a composite structure is inevitable. However, its presence automatically changes the stress distribution pattern in the component. The present work analyses the flexural performance of glass/epoxy composite with single and pair holes in different locations and sizes. In paired holes (2 mm diameter), stress concentrations were placed at a distance of 10, 20 and 30 mm. In single hole specimens, the notch locations were at 4, 8 and 12 mm distance with hole diameter of 2, 4 and 6 mm. The work suggests a significant drop (30.21%) of flexural strength with a hole placed at 10 mm, which eventually reduced up to 14 ± 1% with the hole moving further away in a paired configuration. Although, the optimum performance was at 20 mm location with improvement in flexural modulus by 12.27%. The single hole arrangement reiterates the significance of hole location and reports that flexural strength decreases significantly as it moves away from the support end (42.44%). However, this drop is never linear, suggesting a fall between mid-location. The notch size appears as an important element in flexural performance for it changes the stress distribution around the hole and the associated damage propagation. The above analysis supported Weibull statistics and found good agreement with experimental results. [ABSTRACT FROM AUTHOR]

The glass fiber reinforced polymers (GFRP) bars are considered as an alternative to steel reinforcement in certain structures cases due to their non corrosive aspect. Perhaps, they exist with different surface treatment helically wrapped (GFRP-HW) and sand coated (GFRP-S). Thus, each rebar type is performed by a particular bond behavior with the concrete and it affects the concrete crack formations. In the first part of this paper, an experimental and analytical study of the bond behaviour between the (GFRP), rebars and concrete were carried-out. Pull out test tests have been applied on concrete cylindrical slabs in order to identify experimentally the bond behaviour between the self-compacting concrete and GFRP. Various parameters were taken in account in this experimental study: the rebar diameters, the concrete age, and the rebar roughness. Based on the experimental results, the failure mode of the bond specimens, the variation of the bond load, and the bond-slip variation are analyzed. Two failure modes of the GFRP rebars were experimentally identified: the pull-out failure mode and the splitting one. According to the experimental data, it was proven that the GFRP-S rebars and the steel ones exhibit a more bond performant than that of the GFRP-HW rebars. In the second part, an analytical identification of the BPE and the CMR models was established. Subsequently, a tension tie model was extended analytically in order to predict the crack patterns of concrete elements reinforced with the GFRP rebars and steel rebars. The expressions of the cracking parameters issued from the tension tie model have been developed. It can be deduced that the GFRP-HW and GFRP-S reinforced concrete element exhibits a longitudinal strain less than that of the steel reinforcement case. Hence, the GFRP reinforced element undergoes cracks that are characterized by more important width measurements than those of the cracks deduced from the case of the reinforced steel element. Finally, the stress-strain analytical diagram of a GFRP tension member has been plotted and compared to the steel tension element. [ABSTRACT FROM AUTHOR]

In this study, a detailed finite element investigation was conducted to evaluate the performance of glass fibre-reinforced polymer (GFRP) RC precast cap beam to column connections connected with epoxy-anchored reinforcement (epoxy duct connection). The developed model was initially validated against three experimental results with different anchored GFRP reinforcement considering the effect of reinforcement slippage. Different interaction models for slippage simulation were evaluated and discussed. The validated model was then utilized to investigate the effect of anchored length, bar diameters, anchored reinforcement amount, and the geometry of the connection. The results indicate that an optimum anchored length, equal to 25 times the bar's diameter, should be provided. It was also found that the precast beam-to-column element connection should be designed for a moment capacity at least 25% higher than that of the column section. Moreover, a minimum beam width, depth and beam overhanging length of 1.75, 1.6 and 0.25 times the column width respectively were recommended to be considered in design. The results from this study can provide direct guidelines for the design of precast GFRP-RC cap beam to the column connection with epoxy anchored reinforcement, especially in applications where precast elements need to be erected quickly, a novel method that can accelerate the construction of jetties and bridges. [ABSTRACT FROM AUTHOR]

Composite sandwich structures are widely used for their mechanical properties combined to lightweight. However, damage area quantification caused by low velocity impacts represents generally a crucial task in sandwich composites. In the last years, recent advantages of thermographic devices offer new promising and different real-time industrial and engineering applications where lower computation time, accuracy of results and convenient cost are required. The present research deals with the comparison of standard or latest image-processing methods proposed for pulsed thermography regarding their suitability for determining the impact damage area in sandwich materials made of Aluminium core an a GFRP laminated skins. The Infra-Red processed results are compared with the advanced ultrasonic Phased array method commonly employed in the industrial Non-Destructive Testing. Specifically, the damage area quantification is performed by means of an appropriate MATLAB binarization algorithm for the post-processing of acquired thermal and ultrasonic maps. The data results verify the effectiveness of the image-processing thermographic technique combined to advanced processing approaches for the quantitative assessment of impact damage in sandwich component. [ABSTRACT FROM AUTHOR]

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As the landscape of mobility trends continues to evolve, concerted efforts have been made to incorporate Carbon Fiber Reinforced Plastic (CFRP) into automotive components. However, the substantial increase in cost relative to the achieved weight reduction has limited its widespread adoption. Consequently, research endeavors have focused on exploring alternative composite materials, adapting fibers such as glass fibers, natural fibers, and recycled fibers, to reduce the cost of composite components. Of particular interest in the automotive industry is the utilization of Glass Fiber Reinforced Plastic (GFRP) in chassis components like leaf springs. Nevertheless, the development of GFRP leaf springs encounters a significant challenge related to the adhesive strength at the interface between epoxy resin and glass fibers, which is crucial for enhancing fatigue durability. While glass fibers were traditionally paired with unsaturated polyester or vinyl ester matrices, the pursuit of improved durability has led to the adoption of epoxy matrices. Regrettably, this transition has not consistently yielded the expected gains in interfacial adhesion.In light of these challenges, this study systematically compares the interfacial adhesion strength and fatigue endurance performance. For comparison, two coupling agents widely used commercially, amino silane and epoxy silane, were selected. Glass fibers treated with each coupling agent were purchased commercially, and glass fiber-reinforced plastic (GFRP) specimens were fabricated using the HP-RTM (High-Pressure Resin Transfer Molding) method. Static property evaluations and fatigue durability assessments were conducted using the fabricated specimens. The results showed that when epoxy silane was used as the coupling agent, the interlaminar shear strength (ILSS) increased by approximately 7 %. Furthermore, SEM(Scanning Electron Microscopes) analysis confirmed a significant enhancement in interfacial adhesion, providing support for the ILSS evaluation results. Consequently, the fatigue durability performance improved by approximately six-fold. This confirms that the improvement in interfacial adhesion due to the change in coupling agents led to enhanced fatigue durability performance.

In this study, undulations and their influence on the longitudinal compressive strength of a unidirectional glass fiber reinforced polymer (GFRP) composite are investigated theoretically and experimentally. The objective of this research is to explore the failure mechanisms in FRP and to characterize the mechanical properties of FRP as a function of fiber orientation. For this purpose, a multiscale material model is developed that considers a stochastic fiber orientation distribution (FOD) and models matrix fracture-initiated failure. The relationship between compressive strength and undulation is investigated experimentally on standardized specimens made of unidirectional GFRP. The fiber orientations are measured using X-ray computed tomography and ImageJ image analysis, resulting in a binormal distribution of fiber orientations in the series of samples tested. To examine the failure process in detail, the compression tests are simulated using finite element analysis (FEA). Both the FEA results and the measured compressive strengths confirm the model assumption of matrix fracture-initiated failure under longitudinal compressive loading. The presented analytical model realistically represents the correlation of compressive strength with the FOD.

In this paper, the structural performance of exterior fly-ash based concrete beam-column joints reinforced with hybrid glass fiber reinforced polymer (GFRP) and steel bars was studied, to inspect the hybrid concept efficiency under lateral loads. This paper studied two mixes of concrete, normal strength concrete (NC) and fly-ash based concrete (FC), a 20% replacement ratio of the cement weight with superplasticizer is considered in FC mix, which is considered as an environmental-friendly and cost-effective alternative to ordinary Portland cement. Ten joints were tested under the effect of monotonic lateral load experimentally. The studied joints were divided into two groups based on their concrete type, in each group, five joints with different GFRP to steel ratios “from 0% to 100% with an increment of 25%” were tested. The obtained results showed that the fly ash presence in concrete resulted in an average increase in both ductility and load capacity of 18% and 28.3%, respectively. Also, the average total energy absorption increased by 35%, and the average initial and post-yield stiffness increased by 34% and 41%, respectively. Moreover, the ductility index for each model was obtained, the FC model with 75% GFRP to steel ratio achieved the maximum ductility index, so it was considered as the optimum one. After that, the finite element analysis FEA was utilized to study the performance of the tested beam-column joints. The FEA showed identical results compared to the experimental ones concerning energy absorption, load capacity, and model stiffness. Finally, using FEA, a deep parametric study on FC models reinforced with GFRP to steel bars ranging from 60% to 90% was performed to obtain the optimum GFRP to steel reinforcement ratio. Through the performed parametric study, it was found that the optimum range of the reinforcement ratio was 68% to 82%. According to this research, the usage of fly ash in concrete increased RC beam-column joints' efficiency especially when provided with hybrid GFRP and steel reinforcement, in addition to the important environmental impact achieved through the recycling process. It was recommended to utilize the composite reinforcement ranging between 60% to 75% GFRP to steel bars in the presence of fly ash-based concrete for the beam-column joints.

The use of Glass Fiber Reinforced Plastics (GFRP) bars in coastal concrete structures can effectively prevent steel reinforcement corrosion, but research on the evolution of their performance in seawater and alkaline concrete environments is lacking. The analysis of the degradation process and mechanism of GFRP is thoroughly conducted in this paper through various characterization methods of morphology, mechanics, and material tests. Furthermore, the degradation law of GFRP in various erosion environments is assessed via multi-dimensional indexes. The findings indicate that the erosion of GFRP in an alkaline environment result in the debonding of resin and fiber, thereby causing the formation of cracks. As the erosion age and OH- concentration increase, the size of the cracks expands. Since the dissolution rate of the resin composed as part of GFRP is very low, the salt in seawater has minimal impact on the degradation of GFRP. Vickers hardness of the fiber with age decreased linearly and remained unchanged. Meanwhile, Vickers hardness of the resin with age can be divided into three stages: linear decline stage, linear rise stage, and stabilization stage. Under the erosive conditions, a hydrolysis reaction of the resin occurs resulting in the shortening of its molecular chain. The increase of alkalinity in GFRP attributed to the rising of O-H to C-H chemical bond ratio in the environment leads to the debonding of the fiber and resin. As a result, the resin flows out, and the hydrolysis rate slowly increased first, then accelerated, and finally stabilized.

The advantages of glass fibre reinforced polymer (GFRP) pultruded composite profiles, such as their high strength-to-weight ratio, corrosion resistance, and low maintenance costs, have attracted the attention of researchers and end users in structural applications. In spite of this, one of the challenges associated with using GFRP pultruded profiles is their smooth surfaces when bonded with concrete. To address this challenge, this study investigated four different approaches that can be used to improve the bond performance between GFRP pultruded profiles and concrete surfaces. These approaches are the incorporation of glass sand into cement grout, the variation in the size of the sand particles in the grout, the surface preparation of GFRP profiles, and the use of various cement characteristics. The experimental results show that the surface preparation of the GFRP profiles is the most effective method of improving the bond strength between the GFRP profiles and the concrete surface. Additionally, a theoretical model is developed to predict the bond behaviour, and it is observed that the linear elastic theory with the inclusion of the bond surface roughness coefficient is capable of predicting bond behaviour. The overall outcome of the study will assist design engineers and end users in the application of smooth surface GFRP profiles in concrete structures.

The primary drawback of concrete lies in its low tensile strength, prompting the development of various solutions to enhance this aspect. A notable approach is the utilization of Prestressed Reinforced Concrete (PRC) with tendons, aimed at bolstering its tensile strength. As the use of diverse tendon types in the PRC continues to surge, a review becomes imperative to delve into this evolution. Therefore, this study delved into the engineering characteristics, performance, and evolution of different tendon varieties, encompassing both steel and composite options. Despite certain drawbacks associated with employing composite materials such as Fiber Reinforced Polymer (FRP) tendons - such as heightened costs, limited availability of composite materials, and intricate manufacturing processes - there are distinct advantages and merits to incorporating FRP composite tendons in the realm of construction. In this respect, Carbon FRP tendons exhibited superior strength, comparable to their steel counterparts. Glass FRP tendons, lacking metallic components, possessed non-magnetic properties, rendering them resistant to corrosion. Additionally, Aramid FRP tendons boasted low flammability and exceptional resistance to elevated temperatures. Lastly, Basalt FRP tendons offered sustainability, rust resistance, and non-corrosiveness. The findings derived from this review study serve as a valuable resource for researchers seeking to advance the applications of steel tendons and FRP composite materials within the construction industry.

In this study, we produced Aluminum oxide (Al2O3) reinforced carbon fiber and glass fiber reinforced polymer (CFRP, GFRP) composites and investigated mechanical and tribological properties. Al2O3 was dispersed in epoxy resin using a mechanical stirrer. The composites are produced via the hand lay-up method and dried at room temperature for 48 hours. The properties of composites were determined via Archimedes’ method, flexural, impact, hardness and wear tests. The highest flexural strength and hardness were found at 946.3 MPa and 48.7 HBA for 3 wt.% Al2O3 reinforced CFRP, respectively. The highest impact strength was observed at 187.4 kJ/m2 for an un-reinforced GFRP composite. The lowest Coefficient of Friction (COF) and wear depth was found 3 wt.% Al2O3 reinforced GFRP composites.