scholarly journals Influence of Roughness on Shear Bonding Performance of CFRP-Concrete Interface

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1875 ◽  
Author(s):  
Yushi Yin ◽  
Yingfang Fan
Keyword(s):  
Surface Roughness ◽  
Bond Length ◽  
Interfacial Bonding ◽  
Interface Roughness ◽  
Fiber Reinforced ◽  
Bond Slip ◽  
Practical Applications ◽  
Bond Performance ◽  
Bonding Performance ◽  
Concrete Interface

The potential of Fiber Reinforced Polymer (FRP) in the reinforcement of concrete structures has been shown in many studies and practical applications. However, few works have focused systematically on the development of quantitative criteria to measure surface roughness and relate this parameter to the bonding mechanical property. Moreover, some researchers have declared that, if the concrete interface is rougher, the bond performance between FRP and concrete will be increase, However, there is no answer to how rough the surface is. There are limited application standards for engineers to conduct in FRP reinforcement projects. This work evaluated several concrete specimens with three different strengths and six types of interface roughness. A single shear test was conducted to study the influence of surface roughness on the interfacial bonding performance of a carbon fiber-reinforced composite (CFRP)-concrete beam. The results show that, among the six interfaces, a concrete interface with the roughness of 0.44 has the best interfacial bonding performance. An interfacial appearance with the cement mortar almost cleaned away, and almost one fifth of the single coarse aggregate bared will get the best bond performance. Roughness parameters significantly influenced the effective bond length. The effective bond length of the six interfaces experienced an overall decreasing trend as the roughness increased. The bond–slip curves of concrete interfaces with roughness of 0.25–0.44 did not significantly change the rigidity within the brittle region. The rougher the interface was, the shorter the brittle region was. After entering a plasticity stage, the bond–slip curves for the six types of interfaces all declined with different slopes, and the max slip values were 0.04–0.35 mm when debonding failure occurred.

scholarly journals Experimental Assessment on the Flexural Bonding Performance of Concrete Beam with GFRP Reinforcing Bar under Repeated Loading

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Minkwan Ju ◽  
Hongseob Oh
Keyword(s):  
Bond Length ◽  
Repeated Loading ◽  
Variable Loading ◽  
Loading Test ◽  
Variable Amplitude Loading ◽  
Static Test ◽  
Variable Amplitude ◽  
Reinforcing Bar ◽  
Bond Performance ◽  
Bonding Performance

This study intends to investigate the flexural bond performance of glass fiber-reinforced polymer (GFRP) reinforcing bar under repeated loading. The flexural bond tests reinforced with GFRP reinforcing bars were carried out according to the BS EN 12269-1 (2000) specification. The bond test consisted of three loading schemes: static, monotonic, and variable-amplitude loading to simulate ambient loading conditions. The empirical bond length based on the static test was 225 mm, whereas it was 317 mm according to ACI 440 1R-03. Each bond stress on the rib is released and bonding force is enhanced as the bond length is increased. Appropriate level of bond length may be recommended with this energy-based analysis. For the monotonic loading test, the bond strengths at pullout failure after 2,000,000 cycles were 10.4 MPa and 6.5 MPa, respectively: 63–70% of the values from the static loading test. The variable loading test indicated that the linear cumulative damage theory on GFRP bonding may not be appropriate for estimating the fatigue limit when subjected to variable-amplitude loading.

Experimental study on the bond behavior of the CFRP-steel interface under the freeze–thaw cycles

2019 ◽  
Vol 54 (1) ◽  
pp. 13-29 ◽  
Author(s):  
Yu-Yang Pang ◽  
Gang Wu ◽  
Hai-Tao Wang ◽  
Zhi-Long Su ◽  
Xiao-Yuan He
Keyword(s):  
Carbon Fiber ◽  
Bond Length ◽  
Ultimate Load ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Bond Slip ◽  
Freeze Thaw ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

The bond–slip degradation relationship between carbon fiber-reinforced polymer and steel in a freeze–thaw environment is crucial to evaluate the long-term service performance of steel structures strengthened with carbon fiber-reinforced polymer plates. However, limited studies on the durability and long-term performance of the carbon fiber-reinforced polymer-steel-bonded interface are the major obstacle for the application of carbon fiber-reinforced polymer plates in strengthening steel structures. This paper reports an experimental study to investigate the effects of the carbon fiber-reinforced polymer bond length and the freeze–thaw cycles on the bond behavior of the carbon fiber-reinforced polymer-steel-bonded interface. The three-dimensional digital image correlation technique is applied to obtain displacements and strains on the surface of the single-shear specimen. The experimental results present herein include the failure mode, the ultimate load, the carbon fiber-reinforced polymer strain distribution, the displacement distribution, and the bond–slip relationship. The results show that the ultimate load increases with increasing bond length until a certain bond length value is reached, after which the ultimate load remained approximately constant, and the ultimate loads of carbon fiber-reinforced polymer-steel interface decrease gradually under freeze–thaw cycles. The bond–slip parameters degradation models are proposed, and the bond–slip degradation relationship under the freeze–thaw cycles is established. Finally, the bond–slip degradation relationship is confirmed through comparisons with the experimental results.

scholarly journals Experimental Study on Bond Performance of Carbon- and Glass-Fiber Reinforced Polymer (CFRP/GFRP) Bars and Steel Strands to Concrete

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1268
Author(s):  
Jun Zhao ◽  
Xin Luo ◽  
Zike Wang ◽  
Shuaikai Feng ◽  
Xinglong Gong ◽  
...  
Keyword(s):  
Bond Strength ◽  
Bond Length ◽  
Retention Rate ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Bond Performance ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Gfrp Bar ◽  
Strength Retention

FRP bars and steel strands are widely used in civil engineering. In this study, three different types of high-strength reinforcement materials, carbon fiber reinforced polymer (CFRP) bar, glass fiber reinforced polymer (GFRP) bar, and steel strand, were investigated for their interfacial bond performance with concrete. A total of 90 sets of specimens were conducted to analyze the effects of various parameters such as the diameter of reinforcement, bond length, the grade of concrete and stirrup on the bond strength and residual bond strength. The results show that CFRP bars possess a higher bond strength retention rate than steel bars in the residual section. In addition, with the increase in bond length and diameter of the CFRP bar, the residual bond strength decreases, and the bond strength retention rate decreases. Furthermore, the bond strength retention rate of GFRP bars was found to be higher than that of CFRP bars. With the increase in grade of concrete, the bond strength and residual bond strength between GFRP bars and concrete increases, but the bond strength retention rate decreases. With an increase in bond length and diameter of the GFRP bar, the bond strength starts to decrease. Further, stirrup can also increase the bond strength and reduce the slip at the free end of GFRP bars. Moreover, the bond strength retention rate of the steel strand was found to be lower than CFRP and GFRP bar.

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 Effect of Different Bond Parameters on the Mechanical Properties of FRP and Concrete Interface

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2466
Author(s):  
Comfort Mensah ◽  
Zhenqing Wang ◽  
Alex Osei Bonsu ◽  
Wenyan Liang
Keyword(s):  
Ultimate Load ◽  
Image Correlation ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Bond Slip ◽  
Reinforced Polymer ◽  
Peak Shear Stress ◽  
Concrete Blocks ◽  
Length Width ◽  
Concrete Interface

This paper presents double shear tests performed to investigate factors influencing the bond behavior between basalt fiber-reinforced polymer (BFRP), glass fiber-reinforced polymer (GFRP) laminate, and concrete blocks. In detail, thirty-six twin concrete blocks strengthened with the aforementioned FRP types were tested to evaluate the influence of FRP length, width, and thickness, and their bonding behavior. The 2D-DIC (digital image correlation) technique and several strain gauges bonded along the laminate were used to measure the strain distributions of the FRP-to-concrete interface. The failure mode, ultimate load, load–slip, strain distribution, and bond–slip relationships between the laminates and concrete were analyzed. Furthermore, bond–slip curves were compared with some other existing literature models. The results from the experiment showed that the ultimate load, peak bond stress, and slip increased with the increase in the BFRP and GFRP laminates length, width, and thickness. The values of peak shear stress and the corresponding maximum shear slip were significantly different because of the above-mentioned factors’ influence on them. The bond interface that contributes to the bearing of the shear load may grow to an extent and later shift from the loaded end when debonding progresses. Finally, the fractured surfaces of the failed FRP laminates were examined using scanning electron microscope (SEM), revealing that FRP rupture, debonding in concrete, and debonding in an adhesive–concrete interface were the main failure types.

scholarly journals Experimental study on bond performance between GFRP bars and concrete

2020 ◽  
Vol 165 ◽  
pp. 04041
Author(s):  
Fu Decheng ◽  
Wang Bo
Keyword(s):  
Experimental Study ◽  
Bond Strength ◽  
Bond Length ◽  
Concrete Strength ◽  
Bond Failure ◽  
Bond Performance ◽  
Gfrp Bars ◽  
Bonding Performance ◽  
Pull Out ◽  
Gfrp Reinforcement

Based on 27 bonding test of pull-out specimens, the bonding performance between GFRP and concrete was studied systematically. The bond failure between concrete and GFRP includes four stages: microslip stage, linear slip stage, nonlinear slip stage and bond failure stage. The experiment shows that there is no significant correlation between concrete strength and bond strength, bond strength increases with the bond length and decreases with the increase of GFRP reinforcement diameter.

scholarly journals Experimental Studies on Bond Performance of BFRP Bars Reinforced Coral Aggregate Concrete

2019 ◽  
Vol 13 (1) ◽  
Author(s):  
Lei Wang ◽  
Zhaoping Song ◽  
Jin Yi ◽  
Jiayi Li ◽  
Feng Fu ◽  
...  
Keyword(s):  
Failure Modes ◽  
Fiber Reinforced Polymer ◽  
Constitutive Relationship ◽  
Fiber Reinforced ◽  
Ocean Engineering ◽  
Aggregate Concrete ◽  
Bond Slip ◽  
Bond Performance ◽  
Pull Out ◽  
Reinforced Polymer

Abstract Basalt fiber reinforced polymer (BFRP) rebars reinforced coral aggregate concrete is a new type of concrete used in ocean engineering. In order to investigate the bond performance between BFRP rebars and coral concrete, 30 pull-out tests were carried out in 10 groups with different diameters of BFRP rebars, bonding lengths and strength of the coral concrete. The results show that good bonding between BFRP rebars and coral concrete were achieved. The main failure modes can be categorized as BFRP rebars pull out destruction, splitting failure of coral concrete and BFRP rebars fracture. The bond slip ($$\tau{\text{-}}s$$ τ - s ) curves of the BFRP rebars and coral concrete were obtained during the tests. It was found to be similar to the common concrete using fiber reinforced polymer (FRP) bars. The bond-slip relation can be roughly divided into micro-slip phase, slip phase, decline phase, and the residual stress stage. The bond between BFRP rebars and coral concrete increases with the increase of the bond length and diameter of BFRP rebars, but the average bond stress will decrease. Moreover, increasing the strength of coral concrete is effective to improve the bond performance of BFRP rebars. In this paper, the continuous bond slip model (Gao et al. in J Zhengzhou Univ 23:1–5, 2002) was used to represent the $$\tau{\text{-}}s$$ τ - s constitutive relationship of BFRP rebars and coral concrete. The analysis show that the proposed model has a high degree of accuracy in representing $$\tau{\text{-}}s$$ τ - s curve of BFRP rebars and coral concrete.

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