scholarly journals Tensile Strength and Degradation of GFRP Bars under Combined Effects of Mechanical Load and Alkaline Solution

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3533 ◽  
Author(s):  
Qingping Jin ◽  
Peixia Chen ◽  
Yonghong Gao ◽  
Aihua Du ◽  
Dongxu Liu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Alkaline Solution ◽  
Mechanical Load ◽  
Three Dimensional ◽  
Strength Degradation ◽  
Combined Effects ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Stress Levels

Mechanical properties of glass fiber reinforced polymer (GFRP) composites degrade under the combined effects of mechanical load and alkaline solution, affecting the service ability and safety of GFRP reinforced structures. In this study, GFRP bars were loaded with cyclic tension at different stress levels and immersed in alkaline solution for days to investigate the tensile properties and degradation law of GFRP bars. The degradation mechanisms were studied at micro-, meso- and macro-scales with scanning electron microscopy (SEM) and three-dimensional X-ray microscopy, respectively. The results show that tensile strength and degradation rate of GFRP bars are mainly dependent on the different stress levels and alkaline solution. When stress level is higher, the tensile strength degrades more quickly, especially in the early stages of soaking. With the loading and immersion time, the elastic modulus and Poisson’s ratio increase at first and then decrease. The ultimate tensile strain is relatively stable, whereas the ultimate elongation is significantly reduced. A strength-degradation model was proposed and fit well with experimental data, demonstrating that the model can be applied to predict tensile strength degradation under combined effects of the load and alkaline solution.

scholarly journals Combined Effects of Sustained Loads and Wet-Dry Cycles on Durability of Glass Fiber Reinforced Polymer Composites

2017 ◽  
Vol 2017 ◽  
pp. 1-14
Author(s):  
Mengting Li ◽  
Jun Wang ◽  
Weiqing Liu ◽  
Ruifeng Liang ◽  
Hota GangaRao ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Fiber Reinforced Polymer ◽  
Distilled Water ◽  
Combined Effects ◽  
Gfrp Composites ◽  
Glass Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Sustained Loads

This paper deals with durability of glass fiber reinforced polymer (GFRP) composites under the combined effects of sustained tensile loads and wet-dry (WD) cycles. Two different solutions (distilled water and saltwater) were used to imitate the freshwater and marine environments, respectively. Tensile properties of the unconditioned and conditioned specimens were measured to study the durability of GFRP composites under these 2 effects. The response indicated that both tensile strength and elastic modulus increased initially upon WD cycles, which was attributed to both the postcuring of resin and the sustained tensile stress allowing for fastec cure. Further exposure to WD cycles in distilled water or saltwater led to a steady decrease in tensile strength and modulus. WD cycles of saltwater and distilled water have similar effects on the degradation of the tensile properties for unstressed specimens. However, the elastic modulus and elongation at rupture of stressed specimens under WD cycles of saltwater decreased more than those specimens under WD cycles of distilled water. Moreover, increase of sustained loads led to a decrease in tensile strength. Based on Arrhenius method, a prediction model which accounted for the effects of postcure processes was developed. The predicted results of tensile strength and elastic modulus agree well with those obtained from the experiments.

Experimental Study on Bond Behavior of GFRP-to-Cement Mortar

2011 ◽  
Vol 94-96 ◽  
pp. 543-546
Author(s):  
Ning Zhang ◽  
Ai Zhong Lu ◽  
Yun Qian Xu ◽  
Pan Cui
Keyword(s):  
Aluminium Alloy ◽  
Cement Mortar ◽  
Bond Stress ◽  
Reinforcing Bars ◽  
Bond Performance ◽  
Gfrp Bars ◽  
Pull Out ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Average Bond

Direct pull-out tests were performed to evaluate the bond performance of glass fiber-reinforced polymer (GFRP) reinforcing bars in cement mortar. Specimens with different bar diameters and different grouted lengths (i.e., 5d, 10d and 15d, d is the diameter of bars) are prepared for the pull-out tests. For comparison, specimens with plain aluminium alloy bars (AAB) were tested as well. The result shows that the average bond stress between plain aluminium alloy bars and cement is much smaller than that between the deformed GFRP bars and cement; thin GFRP bars tended to have larger average bond stress; the shorter the grouted length, the smaller the maximum average bond stress. Only part of grouted length undertakes the bond stress and the length depends on the shear modulus of GFRP and the surrounding material.

Reinforced Lime Concrete with FRP: An Alternative in the Restoration of Architectural Heritage

2016 ◽  
Vol 851 ◽  
pp. 751-756
Author(s):  
Ana Almerich-Chulia ◽  
E. Fenollosa ◽  
Pedro Martin
Keyword(s):  
Mechanical Characteristics ◽  
Fiber Reinforced Polymer ◽  
Historic Buildings ◽  
Architectural Heritage ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
New Material ◽  
Traditional Structures ◽  
Corrosion Of Steel

Reinforced concrete has been the material mainly used in the repair of traditional structures of historic buildings. However, since the end of the 20th century, it began to question its use, especially for damages arising from corrosion of steel. An alternative is lime concrete reinforced with Glass Fiber Reinforced Polymer (GFRP) bars. Current lime concrete provides a high compressive strength and prevent problems such as cement alkalinity. GFRP bars provide the necessary tensile strength. Its modulus of elasticity and adhesion, improved by various mechanisms, allows good compatibility with concrete lime. Mechanical characteristics of the mixture are studied together to withstand the tensions and compressions in historic buildings. This new material is progressively replacing to Portland cement in the restoration of architectural heritage

Surface Interaction Studies on Glass Fiber Reinforced Polymer Bars

2007 ◽  
Vol 345-346 ◽  
pp. 1217-1220
Author(s):  
Jung Yoon Lee
Keyword(s):  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Interfacial Bond ◽  
Glass Fiber Reinforced Polymer ◽  
Bond Failure ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Frp Bars

The use of fiber reinforced polymer (FRP) bars has been gaining increasing popularity in the civil engineering community due to their favorable properties such as high-strength-to-weight ratio and good corrosion resistance. In order for concrete to be FRP reinforced, there must be interfacial bond between FRP bars and concrete. The interfacial bond behavior of FRP bars to concrete is expected to vary from that of conventional steel bars, since various key parameters that influence bond performance are different. This paper presents the results of an experimental and analytical study on the interfacial surface interaction of glass fiber reinforced polymer (GFRP) bars in high strength concrete cube. The experimental program consisted of testing 54 concrete cubes prepared according to CSA S802-02 standard 1). The split specimens showed that interfacial bond failure of the steel bar occurred due to concrete crushing in front of the bar deformations, while interfacial bond failure of the GFRP bars occurred partly on the surface of the bar and partly in the concrete by peeling of the surface layer of the bar.

scholarly journals Combined Effects of Curing Temperatures and Alkaline Concrete on Tensile Properties of GFRP Bars

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Wen-rui Yang ◽  
Xiong-jun He ◽  
Kai Zhang ◽  
Yang Yang ◽  
Li Dai
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Correlation Equation ◽  
Immersion Test ◽  
Test Methods ◽  
Curing Temperature ◽  
Mechanical Degradation ◽  
Combined Effects ◽  
Scanning Calorimetry ◽  
Gfrp Bars

A significant number of studies have been conducted on the tensile properties of GFRP bars embedded in concrete under different environments. However, most of these studies have been experimentally based on the environmental immersion test after standard-curing and the lack of influence on the tensile properties of GFRP bars embedded in concrete during the curing process of concrete. This paper presents the results of the microscopic structures through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and tensile properties of GFRP bars, which were employed to investigate the combined effects of curing temperatures and alkaline concrete on tensile properties of GFRP bars. The results showed that the higher curing temperature aggravated the influence of the alkaline concrete environment on GFRP bars but did not change the mechanisms of mechanical degradation of the GFRP bars. The influence of different curing temperatures on the tensile strength of GFRP bars was different between the bare bar and bars in concrete. Finally, the exponential correlation equation of two different test methods was established, and the attenuation ratio of the tensile strength of GFRP bars embedded in concrete under different curing temperatures was predicted by the bare test.

scholarly journals Shear Behavior in Beams Reinforced with Glass-Fiber Reinforced Polymer Bars (GFRPB) without stirrups

2021 ◽  
Vol 9 (1) ◽  
pp. 72-78
Author(s):  
Osama Daoud ◽  
Ahmed Fadul
Keyword(s):  
Shear Strength ◽  
Glass Fiber ◽  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Glass Fiber Reinforced Polymer ◽  
Shear Span ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced

The behavior and shear strength of concrete beams reinforced with glass fiber-reinforced polymer (GFRP) bars was investigated. Total of six reinforced concrete beams without stirrups were constructed and tested up to failure. The beams measured 1400 mm long, 150 mm wide and 300 mm deep and were tested in two-points bending with constant shear span 350 mm in all tested beams, and shear span to depth ratio a/d 1.37. The test variable was the reinforcement ratio. The test beams included three beams designed as tension control (T.C) with GFRP bars, three beams designed as compression control (C.C) with GFRP bars. The test results were compared with predictions provided by ACI 440.1R-15 design guideline and proposed equations in the literature. The test results indicated that the relatively low modulus of elasticity of FRP bars resulted in reducing shear strength. In addition, shear strength provided by ACI 440.1R-15 guideline underestimate shear strength capacity in which proposed equations in the literature had given better prediction than ACI 440.1R-15. The failure mode in T.C beams is diagonal tension by bond failure not by rupture of FRP and C.C beams is shear compression by crushing of the web in extreme fiber.  

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