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Journal ArticleDOI

Effect of combined fatigue and hygrothermal loading on structural properties of E-glass/polymers:

TL;DR: In this paper, the potential ingress and combined effect of moisture and temperature on pre-fatigued glass fiber-reinforced polymers standard test specimens were analyzed in environmental conditions similar to that of tropical environments.
Abstract: The paper discusses the potential ingress and combined effect of moisture and temperature on pre-fatigued glass fibre-reinforced polymers standard test specimens. An experimental investigation was conducted to analyse the behaviour of glass fibre-reinforced polymers’ in environmental conditions similar to that of tropical environments. The standard pre-fatigued glass fibre-reinforced polymers specimens were subjected to varying hygrothermal conditions: three different temperatures, i.e. natural bath, 45 ℃ and 55 ℃ to study the degradation in strength and related properties. Several macro-structural and micro-structural tests were conducted to determine the damage. The effect of these conditions on characteristics such as diffusivity, weight gain, resin volume fraction, conductivity and deterioration of ultimate tensile strength was determined. The maximum reduction in strength is found to be approximately 39% for the specimen exposed to 55 ℃ water bath for 60 days. This study shall be helpful in estimatin...
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Journal ArticleDOI
TL;DR: In this article, the effect of fiber orientation and hygrothermal aging on moisture diffusivity, FTIR spectra, glass transition temperature, and static strength was investigated.

23 citations

Journal ArticleDOI
TL;DR: In this paper , the authors investigated the durability of glass-fiber-reinforced polymer (GFRP) pultruded profiles made of unsaturated polyester (UP) and vinylester (VE) resins commonly used in civil engineering.
Abstract: This paper presents the results of experimental investigations on the durability of glass-fiber-reinforced polymer (GFRP) pultruded profiles made of unsaturated polyester (UP) and vinylester (VE) resins commonly used in civil engineering. The water absorption, tensile properties, and microstructures of GFRP profiles exposed to several typical accelerated aging environments (e.g., deionized water, salt water, salt fog, and combined hygrothermal cycles) for 12 months were investigated. Moreover, a sustained loading factor was included in the test to reflect the behavior of the GFRP profiles in real structures. A normalization approach based on the controlled specimens was used to assess the effectiveness and relevance of the accelerated exposure. The results indicated that the maximum moisture absorption of both UP and VE GFRP profiles was immersed in deionized water, where the masses increased by 1.03 and 0.53%, respectively, leading to the maximum degradation of tensile strength (24.03%) of UP GFRP profile immersion in deionized water after 360 days of aging. However, the tensile modulus was more sensitive to high temperatures and has the maximum degradation (47.03%) after hygrothermal cycles. Moreover, VE GFRP profiles show superior humidity and temperature endurance. Furthermore, the sustained loading exacerbated the degradation of tensile properties slightly under the same conditions. Finally, by incorporating the cumulative damage caused by the sustained loading and a time-dependent factor into a residual strength model, a revised model was proposed to describe the tensile strength loss of pultruded UP GFRP profiles.

2 citations

Journal ArticleDOI
TL;DR: In this paper , the failure characteristics and problem of insufficient bonding strength of the first interface of FRP anchor anchoring slope were discussed, and the improvement was introduced, and a detailed introduction is also given to biomaterials, which are mainly derived from nature and which will not only reduce waste disposal problems and environmental pollution but will also replace conventional applications.
Abstract: Abstract The performance deterioration of steel anchors caused by steel corrosion is becoming more serious in slope anchorage applications. Therefore, the fiber reinforced plastic (FRP) composites have become a substitute material for traditional anchorage structures due to their advantages of low price, lightweight, high strength, and corrosion resistance. Numerous studies have proven that FRP anchors have better anchoring capacity than traditional steel anchors in practical engineering and are not as susceptible to environmental influences. This review mainly introduced the mechanical properties of FRP, focuses on the current research progress and innovation of FRP anchor in anchorage engineering, then provides a basis for the design of FRP anchor. In this study, the failure characteristics and problem of insufficient bonding strength of the first interface of FRP anchor anchoring slope were discussed, and the improvement was introduced. It will be conducive to the extension and application of FRP composites as structural materials in civil engineering. A detailed introduction is also given to biomaterials, which are mainly derived from nature and which will not only reduce waste disposal problems and environmental pollution but will also replace conventional applications. Finally, there will be an important reference and value for the development of green and sustainable engineering structures.

1 citations

Journal ArticleDOI
TL;DR: In this article , the effect of hygrothermal aging on the mechanical performance of fiber reinforced polymeric composites (FRPCs) is reviewed and various damage prediction models are discussed in detail.
References
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Journal ArticleDOI
TL;DR: In this article, the authors conducted an experimental and theoretical comparison between flexural behaviors of concrete beams reinforced with fiber reinforced plastic (FRP) reinforcing bars and identical conventionally reinforced ones.
Abstract: The authors conducted an experimental and theoretical comparison between flexural behaviors of concrete beams reinforced with fiber reinforced plastic (FRP) reinforcing bars and identical conventionally reinforced ones. Comparisons were made in relation to cracking behavior, load-carrying capacities and modes of failure, load-deflection response, flexural rigidity, and strain distribution. The results revealed that perfect bond exists between FRP reinforcing bars and the surrounding concrete. Also, American Concrete Institute (ACI) Code formulas for predicting deflection response, cracking-ultimate moments, and cracked-effective moments of inertia can easily be adapted for modeling the flexural behavior of concrete beams reinforced with FRP reinforcing bars if appropriate modifications are made.

283 citations

01 Jan 1993
TL;DR: In this paper, the authors present an overview of FRP reinforcement for prestressed and non-prestressed concrete structures in Japan and an international perspective on R&D, design/code and technical committees.
Abstract: Part 1 Introductory topics: FRP reinforcement for prestressed and non-prestressed concrete structures, A. Nanni FRP reinforcement - materials and manufacturing, C.E. Bakis properties of FRP reinforcements for concrete, L.C. Bank. Part 2 International perspective: a Canadian perspective on R&D, design/code and technical committees, M.A. Erki and S.H. Rizkalla FRP developments and applications in Europe, L.R. Taerwe an overview of R&D in Japan, Y. Sonobe FRP development in the United States, C. Dolan. Part 3 FRP reinforcement products: 1-D reinforcing systems - glass FRP reinforcing bars for concrete, S.S. Faza and H.V.S. GangaRao, properties and applications of vinylon FRP rod (CLATEC rod), M. Okazaki, CFCC (carbon FRP cable), N. Santoh, testing and application of prestressed concrete beams with CFRP tendons, T. Katou and N. Hayashida, TECHNORA, an aramid FRP rod, K. Noritake et al, FiBRA, T. Tamura, glass fibre prestressing system, R. Wolff and H.J. Miesseler, PARAFIL ropes for prestressing applications, C.J. Burgoyne 2-D and 3-D reinforcing systems - NEFMAC - grid type reinforcement, M. Sugita, three-dimensional fabric reinforcement, H. Nakagawa et al, new three-dimensional FRP reinforcement, T. Yonezawa et al external reinforcing systems - FRP bonded sheets, U. Meier et al, a retrofitting method for reinforced concrete structures using carbon fibre, Y. Kobatake et al.

205 citations

Journal ArticleDOI
TL;DR: In this paper, the authors argue that the working-stress method is better suited for FRP-reinforced concrete structures and that the predicted ultimate moment capacity represents a highly variable state only attainable at a high level of deformation and crack opening and that depends strictly on concrete ultimate strain.
Abstract: Flexural design for concrete members reinforced with fiber‐rein‐forced‐plastic (FRP) composites may be conducted using both the ultimate‐strength method and the working‐stress method. Since FRP reinforcement does not yield, there should be the explicit provision that failure be controlled by concrete crushing as opposed to reinforcement rupture. Deflection control may become as important as flexural strength for the design of FRP‐reinforced concrete structures. The paper contends that, at this stage of development, the working‐stress method is better suited to FRP‐reinforced concrete. The primary reasons are that the predicted ultimate moment capacity represents a highly variable state only attainable at a high level of deformation and crack opening and that it depends strictly on concrete ultimate strain. FRP reinforcement is better suited to pre‐ and posttensioned‐type concrete members; however, it cannot be ruled out that FRP should become the reinforcement of choice in special nonprestressed applicati...

195 citations

Journal ArticleDOI
TL;DR: In this paper, the properties of an E-glass/epoxy composite were examined before and after mechanical loading and moisture conditioning, and the results indicated that the modulus, strength, and strain of the composite material are affected by the presence of moisture and mechanical loading when compared to control specimens.

174 citations


"Effect of combined fatigue and hygr..." refers background in this paper

  • ...Email: abhineet.saini04@gmail.com to hygrothermal conditions.11,12 The use of surface coatings on E-glass fibre has resulted in increased thermal resistance in case of GFRP.13 Previous studies have shown the effect of static as well as dynamic loading on the service life of GFRP composites used for aerospace and structural applications.14–18 The combined influence of impact and hygrothermal loading at varying temperatures, for different glass fibre laminates, has been examined for crack propagation leading to reduced stiffness of the fibre.19 Additionally, the effect of water absorption in hygrothermal loading, resulting in strength degradation of GFRP composites has also been reported.20 The experimental studies suggest different causes of failure in GFRP specimens, with delamination being the most prominent one.7,21,22 However, there is a limited study on dynamic fatigue behaviour of GFRP specimen, with few specific works being reported on laminated and fault-induced composites subjected to axial cyclic loading conditions.23 The present study aims to provide an insight on the simultaneous effect of fatigue and hygrothermal loading on the strength of GFRP composites....

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  • ...The use of surface coatings on E-glass fibre has resulted in increased thermal resistance in case of GFRP.(13) Previous studies have shown the effect of static as well as dynamic loading on the service life of GFRP composites used for aerospace and structural applications....

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  • ...It has previously been reported that there are microstructural changes, like fibre circularity distortion, occurring due to moisture gain in hygrothermal ageing of GFRP specimens.24,25 It has also been discussed by researchers for mutual dependence of macro properties of GFRP specimens, like weight gain, diffusivity and capacitance on each other, and on the strength degradation under moist conditions.26 Therefore, an experimental study was conducted to understand the nature and the level of relationship between various micro- and macro-parameters in combined fatigue and hygrothermal loading of GFRP....

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Journal ArticleDOI
TL;DR: In this paper, the bond characteristics of four different types of glass fiber reinforced plastic (GFRP) reinforcing bars with different surface deformations were analyzed in experiments, and the authors found that small surface indentations were sufficient to yield bond strengths comparable to that of steel bars.
Abstract: The bond characteristics of four different types of glass fiber reinforced plastic (GFRP) reinforcing bars with different surface deformations were analyzed in experiments. Local bond stress-slip data, as well as bond stress-radial deformation data, needed for constitutive modeling of the interface mechanics, were obtained for varying levels of confining pressure. In addition to bond stress and slip, radial stress and radial deformation were considered fundamental variables needed to provide for configuration-independent relationships. Each test specimen consisted of a #6 GFRP reinforcing bar embedded in a 76-mm (3-in)-diameter, 102-mm (4-in)-long cracked concrete cylinder subjected to a controlled, constant amount of confining axisymmetric radial pressure. Only 67 mm (2.6 in) of contact was permitted between the bar and concrete. For each reinforcing bar type, bond stress-slip and bond stress-radial deformation relationships were obtained for five levels of confining axisymmetric radial pressure. The researcher found that small surface indentations were sufficient to yield bond strengths comparable to that of steel bars. Effects of deformations on tensile properties were discussed. It was noted that radial pressure is an important parameter that can increase the bond strength threefold.

138 citations


"Effect of combined fatigue and hygr..." refers background in this paper

  • ...Moreover, the tensile strength of GFRP bars is equivalent to steel bars provided the control on bonding pressure for preparing specimens.(5) However, the service life of GFRP is affected by exposure to moisture, leading to diffusivity, which affects mostly the resin/matrix part....

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