Influence of moderate temperatures on the bond between carbon fibre reinforced polymer bars (CFRP) and concrete

Calvet, V.; Valcuende, M.; Benlloch, J.; Cánoves, Joaquín

doi:10.1016/j.conbuildmat.2015.07.053

Cited by 43 publications

(11 citation statements)

References 14 publications

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“…Therefore, when calculating the deflection of an FRP beam after high-temperature exposure, the short-term stiffness reduction factor K b of FRP beam is introduced. Relevant research [ 58 ] shows that the degradation degree of different types of FRP bars is different at high temperature. Considering the influence of FRP bar type, the influence coefficient λ f of FRP bar type is introduced.…”

Section: Theoretical Analysismentioning

confidence: 99%

Experimental and Theoretical Study on Flexural Behavior of GFRP- and CFRP-Reinforced Concrete Beams after High-Temperature Exposure

et al. 2022

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In this study, in order to study the flexural behavior of fiber-reinforced polymer (FRP) bars with reinforced concrete beams under static loads after high-temperature exposure, seven pieces of FRP-reinforced concrete beams were subjected to static bending tests and calculation model derivations. Four-point bending tests were carried out on FRP-reinforced concrete beams after high temperature treatment. The effects of high temperature and types of FRP bars on the cracking load, crack development, deflection and ultimate capacity, and failure mode of concrete beams were investigated. The test results show that the maximum crack width, deflection, and ultimate bearing capacity of GFRP- and CFRP-reinforced concrete beams decrease obviously with a rise in high temperature. After the exposure of 400 °C for 2 h, compared with the behavior of concrete beams at room temperature, the maximum crack width of GFRP and CFRP-reinforced concrete beams increased by 42.9% and 41.7%, respectively, the deflection increases by 103.6% and 22.0%, and the ultimate bearing capacity decrease by 11.9% and 3.9%. Meanwhile, through the analysis of the existing research results and test results, the calculation models for the maximum crack width, deflection, and residual ultimate capacity of FRP-reinforced concrete beams after exposure of high temperature were proposed. For FRP-reinforced concrete beams after high-temperature exposure, the errors between the measured maximum crack width, stiffness, residual bearing capacity, and their corresponding calculated values using the model were mostly less than 10%. The calculated value using the proposed model in this research is in good agreement with the measured value. The mechanical properties of FRP-reinforced high-strength concrete structures after high-temperature exposure can be preliminarily predicted, which provides a new theoretical basis for the application of FRP-reinforced concrete structures.

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Section: Theoretical Analysismentioning

confidence: 99%

Experimental and Theoretical Study on Flexural Behavior of GFRP- and CFRP-Reinforced Concrete Beams after High-Temperature Exposure

et al. 2022

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“…Bild 1c) zeigt einen Stab mit fein strukturierter Oberfläche, entstanden durch Aufbringen eines Gewebes unmittelbar nach der Pultrusion des Kernstabs [11, 12]. Das Aufbringen von Rippen aus Kunstharz (Bild 1d)) [8, 13] oder das Einfräsen von Rillen in einen Stab (Bild 1e)) dient ebenfalls der Verbesserung der Verbundeigenschaften [8, 14–16]. Die Bilder 1f) und 1g) zeigen zwei umwickelte CFK‐Stäbe.…”

Section: Verbundverhalten Von Cfk‐stäbenunclassified

“…Eine weitere Versagensmöglichkeit ist das Abscheren der Betonrippen. Bei Stäben mit wenig ausgeprägten Rippen kann es auch zu einem Durchzwängen des Stabs ohne Abscheren kommen, wobei diesem Versagensmechanismus eine radiale Komprimierung des Kernstabs zugrunde liegt [8, 11, 13, 34, 35].…”

Section: Verbundverhalten Von Cfk‐stäbenunclassified

Verbundverhalten umwickelter CFK‐Stäbe in Beton – Kurzzeituntersuchung der Verbundeigenschaften mittels Pull‐out‐Tests

Hammerl¹,

Stoiber²,

Hämmerle³

et al. 2021

Beton und Stahlbetonbau

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Der Einsatz und die Verfügbarkeit von Bewehrung aus Carbonfaserverbundkunststoff (CFK) steigen stetig, weshalb ein umfangreiches Verständnis der Verbundeigenschaften essenziell ist. Die vorliegende Publikation gibt einen Überblick über unterschiedliche Ausführungsformen von CFK‐Stäben sowie über den Einfluss von ausgewählten Parametern auf das Verbundverhalten. Der Fokus wurde auf Stäbe mit straffer Umwickelung aus CFK‐Fasersträngen gelegt und die Konkurrenzfähigkeit im Vergleich zu anderen, beispielsweise subtraktiv bearbeiteten, eingefrästen Stäben wird aufgezeigt. In 84 Ausziehversuchen wurde das Verbundverhalten von umwickelten CFK‐Stäben in vier Betonarten getestet. Bei den untersuchten Stäben wurden dabei die Wendelbreite und ‐dicke, die Wendelsteigung, der Wendelabstand und der Stabdurchmesser variiert. Die Versuchsergebnisse werden in Verbundspannungs‐Schlupfdiagrammen präsentiert, verglichen und abschließend diskutiert.

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“…Calvet et al [13] studied the effect of exposing different CFRP and steel rebars to various environments (from 5 ºC to 80 ºC) on their bond behaviour to concrete. The CFRP rebars differed on the surface finishing (sand coated, ribbed, deformed and textured) and on the diameter (8 mm or 14 mm); the embedment length in concrete was 5 times the diameter of the rebars, and their Tg (determined through differential scanning calorimetry experiments) varied between 105 ºC to 123 ºC.…”

Section: Literature Reviewmentioning

confidence: 99%

Bond behaviour of sand coated GFRP bars to concrete at elevated temperature – Definition of bond vs. slip relations

Rosa

Firmo

Correia

et al. 2019

Composites Part B: Engineering

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The use of glass fibre reinforced polymer (GFRP) bars as internal reinforcement of new and existing (for rehabilitation or retrofitting) concrete structures has been growing, mainly due to the advantages they present over traditional steel reinforcement, namely their low weight, high strength and corrosion resistance. However, at moderately elevated temperatures, especially when approaching the glass transition temperature (Tg) of the polymeric matrix (usually between 65-150 ºC), the stiffness, strength and bond properties of these rebars are known to be significantly degraded. The first part of this paper presents an experimental investigation comprising tensile and pull-out tests on sand coated GFRP rebars at elevated temperatures; the tensile tests were carried out up to 300 ºC, whereas the pullout tests were performed on GFRP rebars embedded in concrete cylinders at 20 ºC, 40 ºC, 60 ºC, 80 ºC, 100 ºC and 140 ºC; two embedment lengths of the rebars were considered, corresponding to 5 and 9 times their diameter. Specimens were first heated up to the predefined temperature (measured at the GFRP-concrete interface) and then loaded up to failure. The applied load and the slip of the rebars at both loaded and free ends were measured during the pull-out tests. The obtained results confirmed that the stiffness and strength of the GFRP-concrete interface are significantly reduced with temperature increase, especially when the Tg of the GFRP rebars is approached and exceeded. In the second part of the paper, analytical bond vs. slip relations for the GFRP-concrete interface are proposed for each of the tested temperatures; these relations were obtained based on a numerical strategy in which the experimental data from the pull-out tests were used to calibrate the defining parameters of the local bond vs. slip laws. Moreover, the accuracy of two empirical (relaxation) models, proposed by Gibson et al. and Correia et al. in predicting the GFRP-concrete bond strength reduction with temperature was also assessed.

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Influence of moderate temperatures on the bond between carbon fibre reinforced polymer bars (CFRP) and concrete

Cited by 43 publications

References 14 publications

Experimental and Theoretical Study on Flexural Behavior of GFRP- and CFRP-Reinforced Concrete Beams after High-Temperature Exposure

Experimental and Theoretical Study on Flexural Behavior of GFRP- and CFRP-Reinforced Concrete Beams after High-Temperature Exposure

Verbundverhalten umwickelter CFK‐Stäbe in Beton – Kurzzeituntersuchung der Verbundeigenschaften mittels Pull‐out‐Tests

Bond behaviour of sand coated GFRP bars to concrete at elevated temperature – Definition of bond vs. slip relations

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