scholarly journals Tensile and Shear Testing of Basalt Fiber Reinforced Polymer (BFRP) and Hybrid Basalt/Carbon Fiber Reinforced Polymer (HFRP) Bars

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5839
Author(s):  
Kostiantyn Protchenko ◽  
Fares Zayoud ◽  
Marek Urbański ◽  
Elżbieta Szmigiera
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Tensile Testing ◽  
Maximum Shear Stress ◽  
Fiber Reinforced Polymer ◽  
Strength Testing ◽  
Fiber Reinforced ◽  
Shear Testing ◽  
Reinforced Polymer ◽  
Average Maximum

The use of sustainable materials is a challenging issue for the construction industry; thus, Fiber Reinforced Polymers (FRP) is of interest to civil and structural engineers for their lightweight and high-strength properties. The paper describes the results of tensile and shear strength testing of Basalt FRP (BFRP) and Hybrid FRP (HFRP) bars. The combination of carbon fibers and basalt fibers leads to a more cost-efficient alternative to Carbon FRP (CFRP) and a more sustainable alternative to BFRP. The bars were subjected to both tensile and shear strength testing in order to investigate their structural behavior and find a correlation between the results. The results of the tests done on BFRP and HFRP bars showed that the mechanical properties of BFRP bars were lower than for HFRP bars. The maximum tensile strength obtained for a BFRP bar with a diameter of 10 mm was equal to approximately 1150 MPa, whereas for HFRP bars with a diameter of 8 mm, it was higher, approximately 1280 MPa. Additionally, better results were obtained for HFRP bars during shear testing; the average maximum shear stress was equal to 214 MPa, which was approximately 22% higher than the average maximum shear stress obtained for BFRP bars. However, HFRP bars exhibited the lowest shear strain of 57% that of BFRP bars. This confirms the effectiveness of using HFRP bars as a replacement for less rigid BFRP bars. It is worth mentioning that after obtaining these results, shear testing can be performed instead of tensile testing for future studies, which is less complicated and takes less time to prepare than tensile testing.

scholarly journals Effect of Subtropical Natural Exposure on the Bond Behavior of FRP-Concrete Interface

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 967 ◽  
Author(s):  
Xinyan Guo ◽  
Shenyunhao Shu ◽  
Yilin Wang ◽  
Peiyan Huang ◽  
Jiaxiang Lin ◽  
...  
Keyword(s):  
Shear Stress ◽  
Maximum Shear Stress ◽  
Exposure Period ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Bond Behavior ◽  
Reinforced Polymer ◽  
Natural Exposure ◽  
Externally Bonded ◽  
Concrete Interface

Subtropical natural exposure may significantly affect the bonding behavior of fiber reinforced polymer (FRP) externally bonded to concrete. To study the effect of subtropical natural climates on the FRP-concrete interface, natural exposure tests and an analytical approach were carried out on specimens externally bonded with carbon fiber reinforced polymer (CFRP) and basalt fiber reinforced polymer (BFRP). The bilinear bond stress-slip relationships for different exposure periods were derived from the experimental results of the strengthened reinforced concrete (RC) beams. Based on these bond-slip relationships, the full-range behavior of shear stress along the bond length and debonding load can be obtained through the analytical solution. The testing and numerical results showed that subtropical natural exposure can greatly affect the bond behavior of CFRP-concrete and BFRP-concrete interfaces in the early exposure period. In the late exposure period, the bond behavior was basically stable. With the increase of exposure time, the position of maximum shear stress tended to move backward, which indicated that the behavior of the FRP-concrete interface was weakened by natural exposure. Compared to the CFRP-concrete interface, subtropical natural exposure has greater influence on the bond behavior of the BFRP-concrete interface.

Experimental study on the carbon-fiber-reinforced polymer–steel interfaces based on carbon-fiber-reinforced polymer delamination failures and hybrid failures

2020 ◽  
Vol 23 (11) ◽  
pp. 2247-2260 ◽  
Author(s):  
Yu-Yang Pang ◽  
Gang Wu ◽  
Zhi-Long Su ◽  
Xiao-Yuan He
Keyword(s):  
Shear Strength ◽  
Carbon Fiber ◽  
Failure Mode ◽  
Interlaminar Shear Strength ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced ◽  
Interlaminar Shear

The failure mode is crucial to the interfacial bond performance between carbon-fiber-reinforced polymer plates and steel substrates. Existing studies mainly focused on the cohesive failures in the adhesive; however, research on other types of failure modes is still limited. In this article, a series of single-shear bonded joints are prepared to investigate the bond behaviors of the carbon-fiber-reinforced polymer–steel interfaces based on carbon-fiber-reinforced polymer delamination failures and hybrid failures. Three kinds of adhesives—which have different tensile strengths and elastic moduli—and two kinds of carbon-fiber-reinforced polymer plates—which have different interlaminar shear strengths—are used to evaluate the influencing factors of carbon-fiber-reinforced polymer–steel interfaces. The three-dimensional digital image correlation technique is applied to measure the strain and the displacement on the surface of each specimen. The obtained test results include the strain distribution, the ultimate load, the failure mode, the load–slip curves, and the bond–slip relationships. For the carbon-fiber-reinforced polymer delamination mode, the results show that the load at the debonding stage is closely related to the interlaminar shear strength of the carbon-fiber-reinforced polymer plate, and the higher the interlaminar shear strength is, the greater the load. However, for the hybrid mode, the load of the whole test process is independent of the interlaminar shear strength of the carbon-fiber-reinforced polymer plate.

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