Fatigue behavior of FRP–concrete bond under hygrothermal environment

Zheng, X.H.; Huang, Peiyan; Chen, G.M.; Tan, Xingyu

doi:10.1016/j.conbuildmat.2015.07.172

Cited by 62 publications

(33 citation statements)

References 27 publications

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“…where σ and σ are the tensile stresses on FRP and steel bar at x=0, respectively; is the area of FRP, is the area of the steel bar; is the height of the neutral axis of the cross section from the bottom of beam; and is the distance between the steel bar and the top of the beam (shown in Figure 2), respectively. With the Equations (8)(9), the tensile stress of FRP at x = 0 is obtained by:…”

Section: Natural Exposure Effect On Bond-slip Modelsmentioning

confidence: 99%

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

et al. 2020

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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.Polymers 2020, 12, 967 2 of 21 cycles. Under moisture cyclic condition, weakening in bond strength was observed. Cromwell [4] carried out experiments considering water exposure which showed that higher temperatures (above 60 • C) may affect the bond properties, and proposed that exposure time should exceed 10,000 h. Wan [5] found that the bond behavior of the CFRP-concrete interface degraded when the CFRP bonded specimens were submerged in water for eight weeks. Ren [6] studied the bond strength between concrete and FRP after the specimens were subjected to 98% humidity at 40 • C for 1000 h. The influence of the wet-thermal environment on the CFRP-concrete interface was significant. Ramani [7] designed a series of cyclic moisture environments including 50 • C and 100% RH, and 23 • C and 35% RH, room conditions to study the effect of moisture environments on the CFRP-concrete bond. The shear joints were exposed for five weeks before testing, and the results showed that the behavior of the CFRP-concrete bond declined by 28%. Benzarti [8] carried out pull-off tests under an accelerated aging condition (40 • C, RH 95%). It was found that moisture caused a progressive decrease in the strength of the bonded interface. Zheng [9] kept the specimens in an environmental chamber for 14 days; the RH and temperature condition were set as 95% and 60 • C, respectively. The failure mode and behavior of the CFRP-concrete interface changed compared to specimens without environmental impact.From the above literature review, it can be seen that many studies involving the interfacial durability caused by hydrothermal environment focused on the accelerated aging method [10][11][12]. However, many researchers found ...

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Section: Natural Exposure Effect On Bond-slip Modelsmentioning

confidence: 99%

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

et al. 2020

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“…The effects are obvious when the U-sheets are sufficient and well arranged, which indicates the importance of a rational design (Fu et al 2017). However, under hygrothermal or other harmful conditions, the bond between the CFRP sheet and the concrete may deteriorate, which poses a threat to the safety of the strengthened structures (Böer et al 2014;Dong and Hu 2016;Ferrier et al 2016;Karbhari and Ghosh 2009;Khan et al 2010;Mahmoud et al 2011;Pan et al 2015;Sen 2015;Wu et al 2005;Zhang et al 2012;Zheng et al 2015). Hence, it is necessary to explore alternative methods, including me-1 chanical anchorage (El Maaddawy and Soudki 2008;Kalfat et al 2013;Skuturna and Valivonis 2016;Wang and Zhou 2017;Zhou et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Flexural Behaviour of Narrow RC Beams Strengthened with Hybrid Anchored CFRP Sheets

Zhou

Guo

Wang

et al. 2020

ACT

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Premature debonding failure is a serious problem for reinforced concrete (RC) members strengthened with carbon fibre reinforced polymer (CFRP) laminates. Although various mechanical anchorage systems have been proposed to prevent debonding between CFRP and RC beam, these systems are generally difficult to apply to narrow RC beams due to width limitations. In this study, to resolve the debonding problems, an innovative hybrid end-anchorage system was developed, which achieves self-locking of the externally bonded CFRP sheets. To achieve this hybrid anchorage, both ends of the CFRP sheet were wrapped around twin rods, and the sheet was bonded along the length of the tension side of the beam. Then, to fix the twin rods, two L-shaped brackets were bolted on the side of the beams. In total, five RC beam specimens with rectangular cross sections were prepared and strengthened in different manners and then subjected to four-point bending tests. The enhancement effect of the hybrid anchorage on the flexural behaviour of the strengthened RC beams was validated. With a larger CFRP width, the strengthening effect was more notable, especially when the concrete strength grade was higher. Existing formulas were used to calculate the characteristic moments of the strengthened RC beams, including the cracking moment, yield moment and ultimate moment, and the applicability of the models was examined. Based on the test results, the formula for the ultimate moment of the specimens with the end anchorage requires further investigation.Professor,

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“…[7][8][9] The research results showed that the environmental temperature cannot be ignored as the most common influencing factor. [7][8][9] The research results showed that the environmental temperature cannot be ignored as the most common influencing factor.…”

Section: Introductionmentioning

confidence: 99%

“…[7][8][9] The research results showed that the environmental temperature cannot be ignored as the most common influencing factor. Zheng et al 9 found out that the environmental temperature and humidity adversely affected the bonded behaviour of carbon fibre laminate (CFL)-concrete interface. Li et al 8 studied on the effect of boiled water and ultraviolet on concrete beams strengthened with grass fibre-reinforced polymer and CFRP fabrics, and the tested and calculated results show that environmental attacks have considerable effect on structural degradation of FRP-strengthened concrete beams.…”

Section: Introductionmentioning

confidence: 99%

“…At present, the influence of environments on fatigue performance and durability of the RC structures strengthened with FRP has attracted more and more attention in civil engineering field. [7][8][9] The research results showed that the environmental temperature cannot be ignored as the most common influencing factor. Adimi et al 7 found out the fatigue lives of concrete beams strengthened with carbon fibre-reinforced polymer (CFRP) bars Nomenclature: D, Palmgren-Miner accumulated damage; D c , Palmgren-Miner accumulated critical damage; N, fatigue life; N m , average fatigue life; n i , loading cycles under the ith stress level; ΔP mean , average loading amplitude of the vehicle random loading spectrum; P max , average peak load of the vehicle random loading spectrum; P u , ultimate load-bearing capacity of the strengthened beam; S R , loading level of the vehicle random loading spectrum were obviously decreased as temperature was increased from room temperature to 40°C.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fatigue performance of RC beams strengthened with CFRP under coupling action of temperatures and vehicle random loads

Lin

Huang

Guo

et al. 2018

Fatigue Fract Eng Mat Struct

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Considering significant influence of servicing environments and vehicle random loads on fatigue performance of main load‐bearing members of bridges, in this paper, fatigue performance of reinforced concrete bridge structures strengthened with carbon fibre–reinforced polymer under coupling action of environmental temperatures and vehicle random loads was studied. A vehicle random loading spectrum for fatigue tests was simulated and compiled. A fatigue testing method with coupling action of random loads and temperatures was proposed, and 3‐point bending fatigue tests of the reinforced concrete beams strengthened with carbon fibre–reinforced polymer under coupling action of temperatures and vehicle random loads were performed. Effects of temperatures and loading form on the fatigue damage mechanism were preliminarily discussed. A modified Palmgren‐Miner rule and semiempirical fatigue equations were proposed and proved effective.

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Fatigue behavior of FRP–concrete bond under hygrothermal environment

Cited by 62 publications

References 27 publications

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

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

Flexural Behaviour of Narrow RC Beams Strengthened with Hybrid Anchored CFRP Sheets

Fatigue performance of RC beams strengthened with CFRP under coupling action of temperatures and vehicle random loads

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