FRP Reinforcing bars — designs and methods of manufacture (Review of Patents)

Portnov, G. G.; Bakis, Charles E.; Lackey, Ellen; Kulakov, V. L.

doi:10.1007/s11029-013-9355-1

Cited by 25 publications

(15 citation statements)

References 9 publications

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“…By now, FRPs for structural engineering applications mainly use epoxy and vinyl ester (VE) as matrices. Epoxy resin-based FRPs are more widely used for rods, cables, and wet layups, while VE-based ones are more frequently used for rods or bars produced with a pultrusion process [4,11]. It is worth noting that the VE has a similar molecule backbone (Figure 1), which can be cured with free radicals.…”

Section: Introductionmentioning

confidence: 99%

Water Absorption, Hydrothermal Expansion, and Thermomechanical Properties of a Vinylester Resin for Fiber-Reinforced Polymer Composites Subjected to Water or Alkaline Solution Immersion

Yin

Liu

et al. 2019

Polymers

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In the present paper, a vinyl ester (VE) resin, potentially used as a resin matrix for fiber-reinforced polymer (FRP) composite sucker rods in oil drilling, FRP bridge cables, or FRP marine structures, was investigated on its resistance to water and alkaline solution immersion in terms of water uptake, hydrothermal expansion, and mechanical properties. A two-stage diffusion model was applied to simulate the water uptake processes. Alkaline solution immersion led to a slightly higher mass loss (approx. 0.4%) compared to water immersion (approx. 0.23%) due to the hydrolysis and leaching of uncured small molecules (e.g., styrene). Water immersion caused the expansion of VE plates monitored with Fiber Bragg Grating (FBG). With the same water uptake, the expansion increased with immersion temperatures, which is attributed to the increased relaxation extent of the resin molecular networks. Although an obvious decrease of the glass transition temperatures (Tg) of VE due to water immersion (5.4 to 6.1 °C/1% water uptake), Tg can be recovered almost completely after drying. Tensile test results indicate that a short-term immersion (less than 6 months) enhances both the strength and elongation at break, while the extension of the immersion time degrades both the strength and elongation. The modulus of VE shows insensitive to the immersion even at elevated temperatures.

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Section: Introductionmentioning

confidence: 99%

Water Absorption, Hydrothermal Expansion, and Thermomechanical Properties of a Vinylester Resin for Fiber-Reinforced Polymer Composites Subjected to Water or Alkaline Solution Immersion

Yin

Liu

et al. 2019

Polymers

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“…The effects of the tendon’s diameter [15], the bond length [16], the concrete strength [15,17] and the surface characteristics [18,19] on the bond are of major importance [20,21]. Surface features like embedded sand grains were found to be the main contributors to the bond between FRP reinforcements and concrete [22]. The bond of a sand-coated CFRP profile is principally based on adhesion and mechanical interlock between the rough surface of the tendon and its concrete cover.…”

Section: Introductionmentioning

confidence: 99%

Bond Performance of Sand Coated UHM CFRP Tendons in High Performance Concrete

et al. 2017

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Abstract:The bond behaviour of novel, sand-coated ultra-high modulus (UHM) carbon fibre reinforced polymers (CFRP) tendons to high performance concrete (HPC) was studied by a combined numerical and experimental approach. A series of pull-out tests revealed that the failure type can vary between sudden and continuous pull-out depending on the chosen sand coating grain size. Measuring the same shear stress vs. tendon draw-in (τ-δ) curves in the same test set-up, for sand coated CFRP tendons with a longitudinal stiffness of 137 and 509 GPa, respectively, indicated that the absolute bond strength in both cases was not influenced by the tendon's stiffness. However, the τ-δ curves significantly differed in terms of the draw-in rate, showing higher draw-in rate for the UHM CFRP tendon. With the aid of X-ray computed tomography (CT), scanning electron microscopy (SEM) and visual analysis methods, the bond failure interface was located between the CFRP tendon and the surrounding sand-epoxy layer. For further investigation, a simplified finite element analysis (FEA) of the tendon pull-out was performed using a cohesive surface interaction model and the software Abaqus 6.14. A parametric study, varying the tendon-related material properties, revealed the tendon's longitudinal stiffness to be the only contributor to the difference in the τ-δ curves found in the experiments, thus to the shear stress transfer behaviour between the CFRP tendon and the concrete. In conclusion, the excellent bond of the sand-coated UHM CFRP tendons to HPC as well as the deeper insight in the bond failure mechanism encourages the application of UHM CFRP tendons for prestressing applications.

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“…The main forms of these materials are sheet and plate, which are usually externally bonded on the surfaces of structure members. These materials have been proven to be very efficient and convenient in structure strengthening due to their high strength-to-weight ratio with excellent corrosion resistance [1][2][3][4][5]. But there are still some disadvantages in the use of external bonded FRP.…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis of Tensile Mechanical Properties of Sprayed FRP

Zhao

2016

Advances in Materials Science and Engineering

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To study the tensile mechanical properties of sprayed FRP, 13 groups of specimens were tested through uniaxial tensile experiments, being analyzed about stress-strain curve, tensile strength, elastic modulus, breaking elongation, and other mechanical properties. Influencing factors on tensile mechanical properties of sprayed FRP such as fiber type, resin type, fiber volume ratio, fiber length, and composite thickness were studied in the paper too. The results show that both fiber type and resin type have an obvious influence on tensile mechanical properties of sprayed FRP. There will be a specific fiber volume ratio for sprayed FRP to obtain the best tensile mechanical property. The increase of fiber length can lead to better tensile performance, while that of composite thickness results in property degradation. The study can provide reference to popularization and application of sprayed FRP material used in structure reinforcement.

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FRP Reinforcing bars — designs and methods of manufacture (Review of Patents)

Cited by 25 publications

References 9 publications

Water Absorption, Hydrothermal Expansion, and Thermomechanical Properties of a Vinylester Resin for Fiber-Reinforced Polymer Composites Subjected to Water or Alkaline Solution Immersion

Water Absorption, Hydrothermal Expansion, and Thermomechanical Properties of a Vinylester Resin for Fiber-Reinforced Polymer Composites Subjected to Water or Alkaline Solution Immersion

Bond Performance of Sand Coated UHM CFRP Tendons in High Performance Concrete

Experimental Analysis of Tensile Mechanical Properties of Sprayed FRP

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