scholarly journals Sensitivity analysis of stress state and bond strength of fiber-reinforced polymer/concrete interface to boundary conditions in single shear pull-out test

2015 ◽  
Vol 7 (5) ◽  
pp. 168781401558541 ◽  
Author(s):  
Tayyebeh Mohammadi ◽  
Baolin Wan
Keyword(s):  
Sensitivity Analysis ◽  
Stress State ◽  
Bond Strength ◽  
Boundary Conditions ◽  
Fiber Reinforced Polymer ◽  
Polymer Concrete ◽  
Pull Out ◽  
Reinforced Polymer ◽  
Single Shear ◽  
Concrete Interface

Experimental evaluation of the tensile bonding strength of the basalt fiber-reinforced polymer–concrete interface

2020 ◽  
Vol 23 (15) ◽  
pp. 3323-3334
Author(s):  
Buntheng Chhorn ◽  
WooYoung Jung
Keyword(s):  
High Temperature ◽  
Bonding Strength ◽  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Polymer Concrete ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Interface Bonding Strength ◽  
Concrete Interface ◽  
Basalt Fiber Reinforced Polymer

The bonding performance of basalt fiber-reinforced polymer and concrete substrate has a significant effect on the reliability of externally strengthened existing concrete structure, due to being the most vulnerable element to failure in this fiber-reinforced polymer–concrete strengthening system. Its failure can result in the failure of the whole structure. Although many previous researchers have been interested in the tensile bonding strength of carbon fiber-reinforced polymer and glass fiber-reinforced polymer–concrete interface, that of basalt fiber-reinforced polymer–concrete interface has been very limited. Thus, the objective of this study is to experimentally assess the tensile bonding strength of the basalt fiber-reinforced polymer–concrete interface. The effects of high temperature, freezing–thawing cycles, type of resin, and concrete crack widths on the tensile bonding strength are also investigated. The pull-off experiment is conducted according to ASTM D7522/D7522M-15. A total of 205 core specimens of 50 mm diameter and 10 mm depth were taken from 41 concrete beams. The experimental results illustrate that both freezing–thawing and high-temperature condition have a substantial effect on the bonding strength of the basalt fiber-reinforced polymer–concrete interface. Bonding strength was decreased within the range of about 9%–30% when the number of freezing–thawing cycles increases from 100 to 300; likewise, it was decreased up to 30% when the exposure temperature rises to 200°C. Also, the specimens which were repaired to close their cracks by epoxy resin had no significant effect on the bonding strength of basalt fiber-reinforced polymer–concrete interface, when the specimens had crack width of less than 1.5 mm.

Analysis of influence factors on interfacial bond between BFRP bars and seawater sea-sand concrete

2020 ◽  
pp. 073168442094160
Author(s):  
Yuntao Hua ◽  
Shiping Yin ◽  
Zihan Wang
Keyword(s):  
Bond Strength ◽  
Bond Length ◽  
Failure Modes ◽  
Influence Factors ◽  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Bond Slip ◽  
Pull Out ◽  
Reinforced Polymer

In this paper, the influences of parameters such as the bond length, surface textures of reinforcement, reinforcement type and stirrups restraint were considered. Pull-out failure, splitting failure and splitting-pullout failure modes were observed during the test. The slip at the free end always lagged behind the slip at the loading end and the bond-slip curve of ribbed basalt fiber reinforced polymer (BFRP) bars included the micro-slip stage, slip stage, descent stage, and residual stage. Reducing the bond length and using ribbed-sand coated bars were beneficial to improve the bond performance. Increasing the bond length from 2.5 d to 5 d reduced the bond strength by 49.2%. The application of ribbed-sand coated bars instead of plain bars increased the bond strength by 1202.3%. The difference in bond strength between steel bars, BFRP bars and glass fiber reinforced polymer (GFRP) bars was small and the bond strengths of the three were much greater than that of carbon fiber reinforced polymer (CFRP) bars. This was mainly attributed to the different rib forms of the bars. The application of stirrups increased the bond strength by 11.5%, which indicated that the stirrup restraints can improve the bond behavior to a certain extent. Besides, the analysis of the bond-slip curve based on the energy perspective was consistent with test results.

scholarly journals PREDICTIVE MODEL TO THE BOND STRENGTH OF FRP-TO-CONCRETE UNDER DIRECT PULLOUT USING GENE EXPRESSION PROGRAMMING

2019 ◽  
Vol 25 (8) ◽  
pp. 773-784 ◽  
Author(s):  
Yasmin Murad ◽  
Ahmed Ashteyat ◽  
Rozan Hunaifat
Keyword(s):  
Gene Expression ◽  
Tensile Strength ◽  
Bond Strength ◽  
Gene Expression Programming ◽  
Fiber Reinforced Polymer ◽  
Analytical Models ◽  
Maximum Aggregate Size ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Reinforced Polymer

Gene expression programming (GEP) is used in this research to develop an empirical model that predicts the bond strength between the concrete surface and carbon fiber reinforced polymer (CFRP) sheets under direct pull out. Therefore, a large and reliable database containing 770 test specimens is collected from the literature. The gene expression programming model is developed using eight parameters that predominantly control the bond strength. These parameters are concrete compressive strength, maximum aggregate size, fiber reinforced polymer (FRP) tensile strength, FRP thickness, FRP modulus of elasticity, adhesive tensile strength, FRP length, and FRP width. The model is validated using the experimental results and a statistical assessment is implemented to evaluate the performance of the proposed GEP model. Furthermore, the predicted bond results, obtained using the GEP model, are compared to the results obtained from several analytical models available in the literature and a parametric study is conducted to further ensure the consistency of the model by checking the trends between the input parameters and the predicted bond strength. The proposed model can reasonably predict the bond strength that is most fitting to the experimental database compared to the analytical models and the trends of the GEP model are in agreement with the overall trends of the analytical models and experimental tests.

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