Durability Assessment of 15- to 20-Year-Old GFRP Bars Extracted from Bridges in the US. II: GFRP Bar Assessment

Al-Khafaji, Ali F.; Haluza, Rudy T.; Benzecry, Vanessa; Myers, John J.; Bakis, Charles E.; Nanni, Antonio

doi:10.1061/(asce)cc.1943-5614.0001112

Cited by 17 publications

(8 citation statements)

References 16 publications

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“…In these conditions, they predicted tensile strength losses of only 20% and 25% after, respectively, 100 and 200 years at a reference temperature of 6 °C. This trend is more in line with field investigations conducted on real structures, which do not report significant degradation of the GFRP rebars after 5 to 20 years of service [ 26 , 27 , 28 , 29 , 30 , 31 ].…”

Section: Resultssupporting

confidence: 89%

“…Robert et al [11], who investigated the aging behavior of similar GFRP rebars in moist concrete at 20 • C, 40 • C and 50 • C for periods of up to 8 months, also proposed long-term extrapolation based on the Arrhenius approach. In these conditions, they predicted tensile strength losses of only 20% and 25% after, respectively, 100 and 200 years at a reference temperature of 6 • C. This trend is more in line with field investigations conducted on real structures, which do not report significant degradation of the GFRP rebars after 5 to 20 years of service [26][27][28][29][30][31].…”

Section: Long-term Prediction Based On the Arrhenius Approachsupporting

confidence: 72%

“…For instance, Chen et al reported strength losses up to 80% in the case of GFRP rebars aged for 240 days in a solution of pH 12.7 at a temperature of 60 °C [ 3 ]. However, this accelerated aging condition can be considered an excessively harsh environment for GFRP rebars, since field investigations report only minor degradations on GFRP reinforcements extracted from real RC structures after service periods of 5 to 20 years [ 26 , 27 , 28 , 29 , 30 , 31 ]. Besides, the type of polymer matrix was also found to have a large influence on the durability of GFRP rebars under direct immersion [ 12 , 32 ].…”

Section: Introductionmentioning

confidence: 99%

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Accelerated Aging Behavior in Alkaline Environments of GFRP Reinforcing Bars and Their Bond with Concrete

et al. 2021

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This study investigates the durability of glass fiber-reinforced polymer (GFRP) reinforcing bars (rebars) and their bond in concrete. Accelerated aging tests were first conducted on bare rebars that were either subjected to direct immersion in an alkaline solution or previously embedded in concrete before immersion in the solution (indirect immersion). Accelerated aging was conducted at different temperatures of the solution (20 °C, 40 °C and 60 °C) and for various periods up to 240 days. Residual tensile properties were determined for rebars subjected to direct immersion and served as input data of a predictive Arrhenius model. A large decrease in the residual tensile strength assigned to the alkali-attack of glass fibers was extrapolated in the long term, suggesting that direct immersion is very severe compared to actual service conditions. Short-beam tests were also performed on rebars conditioned under direct/indirect immersion conditions, but did not reveal any significant evolution of the interlaminar shear strength (ILSS). In a second part, bond tests were performed on pull-out specimens after immersion in the alkaline solution at different temperatures, in order to assess possible changes in the concrete/GFRP bond properties over aging. Results showed antagonistic effects, with an initial increase in bond strength assigned to a confinement effect of the rebar resulting from changes in the concrete properties over aging, followed by a decreasing trend possibly resulting from interfacial degradation. Complementary characterizations by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy were also carried out to evaluate the effects of aging on the physical/microstructural properties of GFRPs.

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Section: Resultssupporting

confidence: 89%

Section: Long-term Prediction Based On the Arrhenius Approachsupporting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

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Accelerated Aging Behavior in Alkaline Environments of GFRP Reinforcing Bars and Their Bond with Concrete

et al. 2021

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“…The chloride penetration observed in the extracted cores appeared to be due to deicing salt applications, as four out of the five bridges that showed chloride presence had the highest amount of snow per year. In terms of its effect on the extracted GFRP bars, Cuyahoga Bridge that presented chloride penetration reaching the level of reinforcement, also showed a significant reduction in shear strength and a glass transition temperature (Tg) lower than required by the latest ASTM standard (ASTM 7957) (Al-Khafaji et al 2021). A reduction in shear strength would be indicative of fiber/matrix interface degradation (Benmokrane et al 2015), and a reduction in Tg would be indicative of resin degradation.…”

Section: Chloride Penetration Depthmentioning

confidence: 99%

“…To determine the durability conditions of the GFRP bars, laboratory tests to evaluate the physical, chemical and mechanical properties of the bars are generally performed. These tests are discussed in detail in Part II of this two-paper series (Al-Khafaji et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Durability Assessment of 15- to 20-Year-Old GFRP Bars Extracted from Bridges in the US. I: Selected Bridges, Bar Extraction, and Concrete Assessment

et al. 2021

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Glass fiber-reinforced polymer (GFRP) bars have been used in concrete structures as an alternative to steel bars due to their non-corrosive behavior. However, due to the lack of full understanding of long-term performance, their use as internal reinforcement is still limited. To evaluate the durability of in-service GFRP bars under natural exposure, a collaborative project including four organizations investigated the conditions of GFRP bars and their surrounding concrete from bridges with 15 to 20 years of service. The aim of Part I of a two-paper series is to describe the bridge structures, methods of extraction and the results of concrete testing, while Part II focuses on GFRP bar performance. The extracted bars were tested for physical, mechanical and chemical properties and the surrounding concrete was evaluated for chloride penetration, pH, and carbonation depth at the level of reinforcement. Results showed that carbonation and chloride may have reached the depth of the GFRP bars. This paper discusses the process of extraction of the bars, including the location and type of the selected bridges, and the concrete tests performed in terms of procedure, results, and observations.

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Durability of glass FRP bar‐reinforced seawater–sea sand concrete beams under sustained loading in a subtropical coastal environment

Wang,

Zhao,

Liu

et al. 2024

Polymer Composites

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The replacement of conventional bars with fiber‐reinforced polymer (FRP) bars in seawater–sea sand concrete (SSC) structures is a promising method for sustainable construction. To promote the engineering application of the aforementioned structures, the primary objective of this study was to investigate the concerns regarding the durability of SSC beams reinforced with GFRP bars. For this purpose, three‐point bending tests were conducted on GFRP bar‐reinforced SSC beams to examine the coupled effects of sustained loading and exposure to a subtropical coastal environment on the flexural behavior of exposed SSC beams. The test results revealed that SSC beams reinforced with GFRP bars exhibited excellent durability in a subtropical coastal environment. The coupled effect of sustained loading and exposure to the subtropical coastal environment had an insignificant negative influence on the ultimate flexural capacity of GFRP bar‐reinforced SSC beams at 540 days of age. The failure mechanism of the exposed GFRP bar‐reinforced SSC beams was concrete crushing due to overreinforcement. Finally, the flexural capacity of the exposed beams was predicted by a function of the degradation in the tensile strength of the GFRP bars.Highlights The coupled effects of loading and environmental exposure on GFRP‐SSC beams were examined. The failure mechanisms of the exposed GFRP‐SSC beams was investigated. The long‐term flexural capacity of the GFRP‐SSC beams was predicted.

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Durability Assessment of 15- to 20-Year-Old GFRP Bars Extracted from Bridges in the US. II: GFRP Bar Assessment

Cited by 17 publications

References 16 publications

Accelerated Aging Behavior in Alkaline Environments of GFRP Reinforcing Bars and Their Bond with Concrete

Accelerated Aging Behavior in Alkaline Environments of GFRP Reinforcing Bars and Their Bond with Concrete

Durability Assessment of 15- to 20-Year-Old GFRP Bars Extracted from Bridges in the US. I: Selected Bridges, Bar Extraction, and Concrete Assessment

Durability of glass FRP bar‐reinforced seawater–sea sand concrete beams under sustained loading in a subtropical coastal environment

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