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1
Ali, Ahmed H., Brahim Benmokrane, Hamdy M. Mohamed, Allan Manalo, and Adel El-Safty. "Statistical analysis and theoretical predictions of the tensile-strength retention of glass fiber-reinforced polymer bars based on resin type." Journal of Composite Materials 52, no. 21 (February 9, 2018): 2929–48. http://dx.doi.org/10.1177/0021998318755866.
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This paper presents experimental investigation, statistical analysis, and theoretical predictions of tensile-strength retention of glass fiber-reinforced polymer bars, made with vinyl-ester, polyester, or epoxy resins. The durability of glass fiber-reinforced polymer bars was evaluated as a function of time of immersion in alkaline solution. The aging of the three glass fiber-reinforced polymer bar types consisted of immersion glass fiber-reinforced polymer bar samples in an alkaline solution (up to 5000 h) at different elevated exposure temperatures. Subsequently, the physical and tensile properties of the unconditioned bars were compared with that of the conditioned bars to assess the durability performance of the glass fiber-reinforced polymer bars. Microstructure of all of the glass fiber-reinforced polymer bar types was investigated with scanning electron microscopy, energy dispersive spectroscopy, and Fourier transform infrared spectroscopy for both the conditioned and unconditioned cases, to qualitatively explain the experimental results and to assess changes and/or degradation in the glass fiber-reinforced polymer bars. In addition, the long-term performance of glass fiber-reinforced polymer bars was assessed considering the effect of service years, environmental humidity, and seasonal temperature fluctuations. The test results showed that the tensile strength of the glass fiber-reinforced polymer bars was affected by increased immersion time at higher temperatures and the reduction in tensile strength was statistically significantly dependent on the type of resin system. The prediction approach of the glass fiber-reinforced polymer bars based on the environmental reduction factor ( CE) after 200 years indicated that the CE values for vinyl-ester, epoxy, and polyester glass fiber-reinforced polymer bars can be conservatively recommended to 0.81, 0.75, and 0.71, respectively, for a moisture-saturated environment (relative humidity = 100%) and at 30℃. The polyester glass fiber-reinforced polymer bars experienced greater debonding at the fiber–resin interface than the vinyl-ester and epoxy glass fiber-reinforced polymer bars.
2
Nazair, Claude, Brahim Benmokrane, Marc-Antoine Loranger, Mathieu Robert, and Allan Manalo. "A comparative study of the thermophysical and mechanical properties of the glass fiber reinforced polymer bars with different cure ratios." Journal of Composite Materials 52, no. 29 (May 9, 2018): 4105–16. http://dx.doi.org/10.1177/0021998318774833.
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Cure ratio is a key property for the acceptance and use of glass fiber reinforced polymer bars in civil engineering infrastructure. Yet, there have been no reported studies investigating the effect of cure ratio on the physical, thermal, and mechanical properties of the fiber reinforced polymer bars. This paper presents an interlaboratory test program involving four laboratories to evaluate the cure ratio and glass transition temperature of glass fiber reinforced polymer bars from different production lots. The effect of cure ratio on the physical, mechanical, and microstructure of the glass fiber reinforced polymer bars was also evaluated. The results of this study show that the cure ratio significantly affected the glass transition temperature ( Tg) of the glass fiber reinforced polymer bars tested. The results also show that interlaminar shear strength of the glass fiber reinforced polymer bars was affected by the cure ratio but not the physical and tensile properties, microstructure, or chemical composition. The fully cured glass fiber reinforced polymer bars had interlaminar shear strength up to 8% higher than the partially cured bars. Nonetheless, the glass fiber reinforced polymer bars with a cure ratio of only 96% still had properties well above the minimum prescribed physical and mechanical properties for the reinforcing materials in concrete structures.
3
Protchenko, Kostiantyn, Fares Zayoud, Marek Urbański, and Elżbieta Szmigiera. "Tensile and Shear Testing of Basalt Fiber Reinforced Polymer (BFRP) and Hybrid Basalt/Carbon Fiber Reinforced Polymer (HFRP) Bars." Materials 13, no. 24 (December 21, 2020): 5839. http://dx.doi.org/10.3390/ma13245839.
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The use of sustainable materials is a challenging issue for the construction industry; thus, Fiber Reinforced Polymers (FRP) is of interest to civil and structural engineers for their lightweight and high-strength properties. The paper describes the results of tensile and shear strength testing of Basalt FRP (BFRP) and Hybrid FRP (HFRP) bars. The combination of carbon fibers and basalt fibers leads to a more cost-efficient alternative to Carbon FRP (CFRP) and a more sustainable alternative to BFRP. The bars were subjected to both tensile and shear strength testing in order to investigate their structural behavior and find a correlation between the results. The results of the tests done on BFRP and HFRP bars showed that the mechanical properties of BFRP bars were lower than for HFRP bars. The maximum tensile strength obtained for a BFRP bar with a diameter of 10 mm was equal to approximately 1150 MPa, whereas for HFRP bars with a diameter of 8 mm, it was higher, approximately 1280 MPa. Additionally, better results were obtained for HFRP bars during shear testing; the average maximum shear stress was equal to 214 MPa, which was approximately 22% higher than the average maximum shear stress obtained for BFRP bars. However, HFRP bars exhibited the lowest shear strain of 57% that of BFRP bars. This confirms the effectiveness of using HFRP bars as a replacement for less rigid BFRP bars. It is worth mentioning that after obtaining these results, shear testing can be performed instead of tensile testing for future studies, which is less complicated and takes less time to prepare than tensile testing.
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Wei, Minghai, Li Sun, Chunwei Zhang, and Qinghai Wang. "Effect of seawater exposure on compressive behavior of concrete columns reinforced longitudinally with glass fiber reinforced polymer bars." Journal of Composite Materials 52, no. 17 (November 14, 2017): 2289–99. http://dx.doi.org/10.1177/0021998317742957.
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An experimental study was performed to investigate the effect of seawater exposure on the mechanical behavior of concrete columns reinforced longitudinally with glass fiber reinforced polymer (CCR-GFRP) bars. Numerous salt crystals emerged and slight exfoliation was observed after the surfaces of the columns were immersed in seawater for 120 days. The CCR-GFRP failed in either the axial compressive failure or split-crack failure mode. Furthermore, the probability of split-crack failure gradually increased with the duration of seawater exposure. In general, the carrying capacity of the CCR-GFRP initially increased and then decreased as the seawater exposure progressed. The strains of the surface concrete and inner glass fiber reinforced polymer bars continuously increased, but the strain of the glass fiber reinforced polymer bars and probability of the variability of the strain were less than those of the surface concrete. In addition, the bonding between the glass fiber reinforced polymer bars and concrete gradually decreased with increasing diameter of the glass fiber reinforced polymer bars. As the exposure period increased, the bonding between the glass fiber reinforced polymer bars of the same concrete columns weakened significantly.
5
Yue, Qingrui, Zongquan Liu, Rong Li, and Xiaobing Chen. "Experimental investigation into the development length of carbon-fiber-reinforced polymer grids in concrete." Advances in Structural Engineering 20, no. 6 (September 13, 2016): 953–62. http://dx.doi.org/10.1177/1369433216668360.
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Carbon-fiber-reinforced polymer grids have received much attention lately because of many advantages. The force transfer behavior and development length of carbon-fiber-reinforced polymer grid reinforcement were evaluated using a pull-out test method. A total of 18 pull-out specimens of carbon-fiber-reinforced polymer grid reinforcement were tested under monotonic static loading, and the investigated parameters included the concrete compressive strength, the number of embedded transverse bars, with or without transverse bars, and the number of adjacent longitudinal bars. The slips between the reinforcing carbon-fiber-reinforced polymer grids and the concrete were measured at both the free end and the loaded end during the whole loading process. The test results indicated that first, the concrete compressive strength and the adjacent longitudinal bars had little influence on the force transfer behavior, second, the wedge action of the transverse bars was very important for transferring force; thus, increase in number of embedded transverse bars increased the force transfer stiffness and reduced the slippage. In the case of tested carbon-fiber-reinforced polymer grids, three embedded transverse bars equal to embedment length of 150 mm were sufficient to develop full tensile strength. Based on this experimental investigation, the preliminary design principles were also discussed.
6
Protchenko, Kostiantyn, Elżbieta Szmigiera, Marek Urbański, and Andrzej Garbacz. "Development of Innovative HFRP Bars." MATEC Web of Conferences 196 (2018): 04087. http://dx.doi.org/10.1051/matecconf/201819604087.
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The main factors determining the choice of fiber-reinforced polymer (FRP) materials are the intended use of the designed structure and the environmental conditions in which it will be located. Currently, the FRP-based materials have a variety of applications in the construction industry, from the secondary structural elements of buildings, to a complicated designs, where the only FRPs were used. The advances in FRP technology have spurred interest in introducing innovative hybrid fiber-reinforced polymer (HFRP), which potentially can be used as reinforcing/enhancing material. This paper describes the investigation on newly-developed hybrid fiber-reinforced polymer HFRP bars, which were created by modification of basalt fiber-reinforced polymer BFRP bars in terms of physical substituting of the certain amount of basalt fibers by the part of carbon fibers. Modification is aimed at achieving of better properties in obtained material and simultaneously ensuring cost-effectiveness concept. The investigation includes the preparation and numerical considerations on HFRP bars as well as first attempts of experimental structural testing of innovative HFRP bars.
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Salleh, Norhafizah, Abdul Rahman Mohd Sam, Jamaludin Mohd Yatim, and Mohd Firdaus bin Osman. "Flexural Behaviour of Reinforced Concrete Beam with Glass Fiber Reinforced Polymer (GFRP) Bar Strengthened with Carbon Fiber Reinforced Polymer (CFRP) Plate." Advanced Materials Research 1051 (October 2014): 748–51. http://dx.doi.org/10.4028/www.scientific.net/amr.1051.748.
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The use of glass-fiber-reinforced polymer (GFRP) bar to replace steel reinforcement in concrete structures is a relatively a new technique. The GFRP bars possess mechanical properties different from steel bars, including high tensile strength combined with low elastic modulus and linear stress–strain relationship up to failure. Therefore, design procedures and process should account for these properties. This paper presents the experimental work on the flexural behavior of concrete beam reinforced with GFRP bars and strengthen with CFRP plate. A total of ten reinforced concrete beams reinforced with either steel and GFRP bars were cast and tested under four point loads. Eight concrete beams (200x250x2800mm) were reinforced with 13mm diameter GFRP bars together with strengthening using CFRP plate and two control beams reinforced with 12mm diameter steel bars were tested. The experimental results show that although the stiffness of the beams reduced but the ultimate load of the GFRP reinforced concrete beam is bigger than steel reinforced beam. It was also found that strengthening using CFRP plate will further enhanced the flexural performance of the beams with GFRP bars.
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Ghali, Amin, Tara Hall, and William Bobey. "Minimum thickness of concrete members reinforced with fibre reinforced polymer bars." Canadian Journal of Civil Engineering 28, no. 4 (August 1, 2001): 583–92. http://dx.doi.org/10.1139/l01-021.
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To avoid excessive deflection most design codes specify the ratio (l/h)s, the span to minimum thickness of concrete members without prestressing. Use of the values of (l/h)s specified by the codes, in selecting the thickness of members, usually yields satisfactory results when the members are reinforced with steel bars. Fibre reinforced polymer (FRP) bars have an elastic modulus lower than that of steel. As a result, the values of (l/h)s specified in codes for steel-reinforced concrete would lead to excessive deflection if adopted for FRP-reinforced concrete. In this paper, an equation is developed giving the ratio (l/h)f for use with FRP bars in terms of (l/h)s and (εs/εf), where εs and εf are the maximum strain allowed at service in steel and FRP bars, respectively. To control the width of cracks, ACI 318-99 specifies εs = 1200 × 106 for steel bars having a modulus of elasticity, Es, of 200 GPa and a yield strength, fy, of 400 MPa. At present, there is no value specified for εf; a value is recommended in this paper.Key words: concrete, cracking, deflection, fibre reinforced polymers, flexural members, minimum thickness.
9
Zhao, Yajun, Yimiao Huang, Haiyang Du, and Guowei Ma. "Flexural behaviour of reinforced concrete beams strengthened with pre-stressed and near surface mounted steel–basalt-fibre composite bars." Advances in Structural Engineering 23, no. 6 (December 2, 2019): 1154–67. http://dx.doi.org/10.1177/1369433219891595.
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Fibre-reinforced polymer bars have been widely used for strengthening concrete members due to their high strength, light weight and strong corrosion resistance. A near-surface mounted strengthening system has been adopted to protect the fibre-reinforced polymer bars from external hazards. To make up the lower stiffness and ductility of fibre-reinforced polymer bar compared to steel rebar, this study proposed to use a pre-stressed near-surface mounted steel–basalt-fibre-reinforced polymer composite bar. The steel–basalt-fibre-reinforced polymer composite bar is manufactured through wrapping a steel rod by a basalt-fibre-reinforced polymer cover. A total of nine reinforced concrete beams, including one control or calibration and eight others strengthened by pre-stressed near-surface mounted steel–basalt-fibre-reinforced polymer composite bars, are fabricated and tested. Results show that the proposed steel–basalt-fibre-reinforced polymer composite bar strengthening method can improve both the strength and ductility of the reinforced concrete beams. Pre-stressing of the steel–basalt-fibre-reinforced polymer composite bars further increases substantially the beams’ load-carrying capacity by restraining crack propagation in concrete. Standard-based load analysis correctly predicts the cracking load, however, underestimates the ultimate strength of the beams. Finite element method modelling is conducted to provide a more effective load-carrying capacity prediction and a case study is carried out with regard to the amount of the strengthening steel–basalt-fibre-reinforced polymer composite bars.
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Szmigiera, E. D., K. Protchenko, M. Urbański, and A. Garbacz. "Mechanical Properties of Hybrid FRP Bars and Nano-Hybrid FRP Bars." Archives of Civil Engineering 65, no. 1 (March 1, 2019): 97–110. http://dx.doi.org/10.2478/ace-2019-0007.
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AbstractThe paper describes the recent developments of Hybrid Fibre-Reinforced Polymer (HFRP) and nano-Hybrid Fibre-Reinforced Polymer (nHFRP) bars. Hybridization of less expensive basalt fibres with carbon fibres leads to more sustainable alternative to Basalt-FRP (BFRP) bars and more economically-efficient alternative to Carbon-FRP (CFRP) bars. The New-Developed HFRP bars were subjected to tensile axial loading to investigate its structural behaviour. The effect of hybridization on tensile properties of HFRP bars was verified experimentally by comparing the results of tensile test of HFRP bars with non-hybrid BFRP bars. It is worth to mention that the difference in obtained strength characteristics between analytical and numerical considerations was very small, however the obtained results were much higher than results obtained experimentally. Authors suggested that lower results obtained experimentally can be explained by imperfect interphase development and therefore attempted to improve the chemical cohesion between constituents by adding nanosilica particles to matrix consistency.
11
Ghiassi, Bahman, Masoud Soltani, and Sara Rahnamaye Sepehr. "Micromechanical modeling of tension stiffening in FRP-strengthened concrete elements." Journal of Composite Materials 52, no. 19 (January 9, 2018): 2577–96. http://dx.doi.org/10.1177/0021998317751248.
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This article presents a micromodeling computational framework for simulating the tensile response and tension-stiffening behavior of fiber reinforced polymer–strengthened reinforced concrete elements. The total response of strengthened elements is computed based on the local stress transfer mechanisms at the crack plane including concrete bridging stress, reinforcing bars stress, FRP stress, and the bond stresses at the bars-to-concrete and fiber reinforced polymer-to-concrete interfaces. The developed model provides the possibility of calculating the average response of fiber reinforced polymer, reinforcing bars, and concrete as well as the crack spacing and crack widths. The model, after validation with experimental results, is used for a systematic parameter study and development of micromechanics-based relations for calculating the crack spacing, fiber reinforced polymer critical ratio, debonding strength, and effective bond length. Constitutive models are also proposed for concrete tension stiffening and average response of steel reinforcing bars in fiber reinforced polymer–strengthened members as the main inputs of smeared crack modeling approaches.
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Lathamaheswari, R., R. BalaKeerthana, K. Nandhini, B. Parkavi, and A. Nivedha. "Study on GFRP Reinforced Beams under Flexure." International Journal of Emerging Research in Management and Technology 6, no. 7 (June 29, 2018): 156. http://dx.doi.org/10.23956/ijermt.v6i7.205.
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Acute shortage of raw materials and deterioration of reinforced concrete structural elements lead to implementation of new substitute materials and innovative technologies. Reinforced Cement Concrete structures are usually reinforced with steel bars which are subjected to corrosion at critical temperature and atmospheric conditions. The structures can also be reinforced with other materials like Fibre Reinforced Polymers (FRP). In this line Fibre Reinforced Polymer based reinforcement replacing conventional steel rod for a precast element of a prefabricated structure is considered. The precast member cast out of M25 grade concrete reinforced exclusively with locally produced Glass Fibre Reinforced Polymer (GFRP) bars including GFRP stirrups is designed, cast. Flexural behaviour of rectangular concrete beams reinforced with FRP bars and stirrups is examined with two specimens one with conventional sand as fine aggregate and another with quarry dust as fine aggregate. The load at cracking and ultimate, type of failure and crack patterns are observed and compared with those of conventional cement concrete.
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Lee, Jung Yoon. "Surface Interaction Studies on Glass Fiber Reinforced Polymer Bars." Key Engineering Materials 345-346 (August 2007): 1217–20. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.1217.
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The use of fiber reinforced polymer (FRP) bars has been gaining increasing popularity in the civil engineering community due to their favorable properties such as high-strength-to-weight ratio and good corrosion resistance. In order for concrete to be FRP reinforced, there must be interfacial bond between FRP bars and concrete. The interfacial bond behavior of FRP bars to concrete is expected to vary from that of conventional steel bars, since various key parameters that influence bond performance are different. This paper presents the results of an experimental and analytical study on the interfacial surface interaction of glass fiber reinforced polymer (GFRP) bars in high strength concrete cube. The experimental program consisted of testing 54 concrete cubes prepared according to CSA S802-02 standard 1). The split specimens showed that interfacial bond failure of the steel bar occurred due to concrete crushing in front of the bar deformations, while interfacial bond failure of the GFRP bars occurred partly on the surface of the bar and partly in the concrete by peeling of the surface layer of the bar.
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Kosior-Kazberuk, Marta. "Application of basalt-FRP bars for reinforcing geotechnical concrete structures." MATEC Web of Conferences 265 (2019): 05011. http://dx.doi.org/10.1051/matecconf/201926505011.
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The fiber reinforced polymer (FRP) bars have become a useful substitute for conventional reinforcement in civil engineering structures for which load capacity and resistance to environmental influences are required. They are often used in concrete structural elements exposed to strong environmental aggression, such as foundations, breakwaters and other seaside structures, road structures and tanks. The basalt fiber-reinforced polymer (BFRP) is the most recently FRP composite, appearing within the last decade. Due to their mechanical properties different from steel bars, such as higher tensile strength and lower Young's modulus, BFRP bars are predestined for use in structures for which the ultimate limit state is rather decisive than serviceability limit state. Experimental tests were carried out to assess the influence of static long-term loads and cyclic freezing/thawing on the behaviour of concrete model beams with non-metallic reinforcement. The bars made of basalt fiber reinforced polymer (BFRP) and hybrid (basalt and carbon) fiber reinforced polymer (HFRP) were used as non-metallic reinforcement. The mechanical properties of both types of bars were also determined.
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Dong, Zhiqiang, Gang Wu, Xiao-Ling Zhao, Hong Zhu, and Jin-Long Lian. "The durability of seawater sea-sand concrete beams reinforced with metal bars or non-metal bars in the ocean environment." Advances in Structural Engineering 23, no. 2 (August 24, 2019): 334–47. http://dx.doi.org/10.1177/1369433219870580.
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In this article, the flexural durability of three types of seawater sea-sand concrete beams that were fully reinforced with steel bars, 304 stainless steel bars, or fiber-reinforced polymer bars were comparatively tested. Beam specimens were conditioned in a 40°C seawater wet–dry cycling environment and a 50°C seawater immersion environment for up to 9 months with an interval of 3 months. The test results showed that in the absence of an additional current (even if the temperature is elevated), the flexural properties of the seawater sea-sand concrete beams reinforced with steel bars and stainless steel bars after 9 months of conditioning did not show any degradation trends. However, for the carbon fiber–reinforced polymer bar–reinforced beams (top bars and stirrups are both basalt fiber–reinforced polymer bars) conditioned in the high-temperature and high-humidity environment considered, the failure modes changed from concrete crushing in the pure bending section to concrete crushing at loading points in the shear span with a maximum reduction of 30% in the ultimate load-carrying capacity. In addition, the crack distribution of conditioned carbon fiber–reinforced polymer bar–reinforced beams became sparse, and the crack width increased significantly, with a maximum of 2.2 times. In addition, obvious sudden load drops were observed in the tested load–displacement curves.
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Benmokrane, Brahim, Burong Zhang, Kader Laoubi, Brahim Tighiouart, and Isabelle Lord. "Mechanical and bond properties of new generation of carbon fibre reinforced polymer reinforcing bars for concrete structures." Canadian Journal of Civil Engineering 29, no. 2 (April 1, 2002): 338–43. http://dx.doi.org/10.1139/l02-013.
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This paper presents laboratory test results on the mechanical properties and bond strength of new generation of carbon fibre reinforced polymer (CFRP) reinforcing bars used as nonprestressed reinforcement for concrete structures. Two types of CFRP reinforcing bars, namely, 9-mm-diameter CFRP ribbed bars and 9.5-mm-diameter CFRP sand-coated bars, were investigated. Tensile tests and pullout bond tests were conducted to evaluate the tensile properties and bond strength of the CFRP bars in comparison with that of the steel bar. Experimental results showed that the tensile stress-strain curves of the CFRP bars were linear up to failure. The ultimate tensile strength of the two types of CFRP bars was at least 1500 MPa, three times that of steel bars. The modulus of elasticity of two types of the CFRP bars was 128145 GPa, about 6575% that of steel. Furthermore, both types of the CFRP bars exhibited almost the same bond strength to concrete similar to steel bars. The minimum bond development length for the two types of CFRP bars seemed to be equal to about 20db for the sand-coated bars and 30db for the ribbed bars.Key words: fibre reinforced polymer (FRP), carbon FRP (CFRP), bar, mechanical properties, tensile strength, embedded length, pullout, bond strength, concrete structures.
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Ogrodowska, Karolina, Karolina Łuszcz, and Andrzej Garbacz. "The effect of temperature on the mechanical properties of hybrid FRP bars applicable for the reinforcing of concrete structures." MATEC Web of Conferences 322 (2020): 01029. http://dx.doi.org/10.1051/matecconf/202032201029.
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One of the most common causes of the deterioration of concrete structures is the corrosion of steel reinforcement. Reinforcement made from fiber reinforced polymers (FRP) is considered to be an attractive substitution for traditional reinforcement. The most popular FRP reinforcing bars are made of glass fibers. Basalt fiber reinforced polymer (BFRP) is a relatively new material for reinforcing bars. The main drawback of BFRP bars is their low modulus of elasticity. A new type of bar made from hybrid fiber reinforced polymer (HFRP) in which a proportion of the basalt fibers are replaced with carbon fibers can be considered as a solution to this issue; such a bar is presented in this work. The HFRP bars might be treated as a relatively simple modification to previously produced BFRP bars. A different technical characteristic of the fibre reinforced polymer makes the designing of structures with FRP reinforcement differ from conventional reinforced concrete design. Therefore, it is necessary to identify the differences and limitations of their use in concrete structures, taking into account their material and geometric features. Despite the predominance of FRP composites in such aspects as corrosion resistance, high tensile strength, and significant weight reductions of structures – it is necessary to consider the behavior of FRP composites at elevated temperatures. In this paper, the effect of temperature on the mechanical properties of FRP bars was investigated. Three types of FRP bar were tested: BFRP, HFRP in which 25% of basalt fibers were replaced with carbon fibers and nHFRP in which epoxy resin was additionally modified with a nanosilica admixture. The mechanical properties were determined using ASTM standard testing for transverse shear strength. The tests were performed at -20°C, +20°C, +80°C for three diameters of each types of bar.
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Zhang, Pu, Shuangquan Zhang, Danying Gao, Fang Dong, Ye Liu, Jun Zhao, and Shamim A. Sheikh. "Influence of rib parameters on mechanical properties and bond behavior in concrete of fiber-reinforced polymer rebar." Advances in Structural Engineering 24, no. 1 (August 12, 2020): 196–208. http://dx.doi.org/10.1177/1369433220947196.
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Mechanical properties of fiber-reinforced polymer rebar and bond behavior between the fiber-reinforced polymer rebar and concrete are highly related to rib parameters, including rib depth and rib spacing. Therefore, rib parameters should be taken into account when fiber-reinforced polymer bars are used as the structure reinforcement. In this article, the tensile properties of glass-fiber-reinforced polymer rebars with different rib depths and rib spacings are tested. The influences of different rib depths and rib spacings on the bond behavior between glass-fiber-reinforced polymer rebar and concrete are investigated by pull-out test. Experimental results show that the rib depth has a distinctive effect on the ultimate tensile strength, elastic modulus, and ultimate elongation of glass-fiber-reinforced polymer rebar. The tensile strength and elastic modulus of glass-fiber-reinforced polymer rebar with shallow rib are remarkably higher than those of glass-fiber-reinforced polymer bars with deep rib. However, compared with the glass-fiber-reinforced polymer bars with shallow rib, the glass-fiber-reinforced polymer bars with deep rib contribute larger bond strength with concrete. Besides, the bond strength and basic anchorage length are predicted by taking rib depth and rib spacing into account. A modified Bertero–Popov–Eligehausen model is adopted to simulate the bond stress–slip behavior, and the ascending branch of bond stress–slip curve expressed by rib depth and rib spacing is also proposed. The calculated results are in good agreement with the test ones.
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Tudgey, G. F. "An Improved Method for the preparation of High Quality Carbon Fibre Composite Test Bars." Advanced Composites Letters 2, no. 6 (November 1993): 096369359300200. http://dx.doi.org/10.1177/096369359300200605.
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The properties of carbon fibre composites derived from novel matrix polymers are often required for evaluation. An improved method has been developed to enable the preparation of unidirectional carbon fibre composite test bars of uniform high quality using only small quantities of matrix polymer.
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Urbański, Marek. "Compressive Strength of Modified FRP Hybrid Bars." Materials 13, no. 8 (April 17, 2020): 1898. http://dx.doi.org/10.3390/ma13081898.
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A new type of HFRP hybrid bars (hybrid fiber reinforced polymer) was introduced to increase the rigidity of FRP reinforcement, which was a basic drawback of the FRP bars used so far. Compared to the BFRP (basalt fiber reinforced polymer) bars, modification has been introduced in HFRP bars consisting of swapping basalt fibers with carbon fibers. One of the most important mechanical properties of FRP bars is compressive strength, which determines the scope of reinforcement in compressed reinforced concrete elements (e.g., column). The compression properties of FRP bars are currently ignored in the standards (ACI, CSA). The article presents compression properties for HFRP bars based on the developed compression test method. Thirty HFRP bars were tested for comparison with previously tested BFRP bars. All bars had a nominal diameter of 8 mm and their nonanchored (free) length varied from 50 to 220 mm. Test results showed that the ultimate compressive strength of nonbuckled HFRP bars as a result of axial compression is about 46% of the ultimate strength. In addition, the modulus of elasticity under compression does not change significantly compared to the modulus of elasticity under tension. A linear correlation of buckling load strength was proposed depending on the free length of HFRP bars.
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G. Karayannis, Chris, Parthena-Maria K. Kosmidou, and Constantin E. Chalioris. "Reinforced Concrete Beams with Carbon-Fiber-Reinforced Polymer Bars—Experimental Study." Fibers 6, no. 4 (December 14, 2018): 99. http://dx.doi.org/10.3390/fib6040099.
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Innovative reinforcement as fiber-reinforced polymer (FRP) bars has been proposed as alternative for the substitution of the traditional steel bars in reinforced concrete (RC) structures. Although the advantages of this polymer reinforcement have long been recognised, the predominantly elastic response, the reduced bond capacity under repeated load and the low ductility of RC members with FRP bars restricted its wide application in construction so far. In this work, the behavior of seven slender concrete beams reinforced with carbon-FRP bars under increasing static loading is experimentally investigated. Load capacities, deflections, pre-cracking and after-cracking stiffness, sudden local drops of strength, failure modes, and cracking propagation have been presented and commented. Special attention has been given in the bond conditions of the anchorage lengths of the tensile carbon-FRP bars. The application of local confinement conditions along the anchorage lengths of the carbon-FRP bars in some specimens seems to influence their cracking behavior. Nevertheless, more research is required in this direction. Comparisons of experimental results for carbon-FRP beams with beams reinforced with glass-FRP bars extracted from recent literature are also presented and commented. Comparisons of the experimental results with the predictions according to ACI 440.1R-15 and to CSA S806-12 are also included herein.
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Baghani, Mostafa, Reza Naghdabadi, Jamal Arghavani, and Saeed Sohrabpour. "A constitutive model for shape memory polymers with application to torsion of prismatic bars." Journal of Intelligent Material Systems and Structures 23, no. 2 (January 2012): 107–16. http://dx.doi.org/10.1177/1045389x11431745.
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In this article, satisfying the second law of thermodynamics, we present a 3D constitutive model for shape memory polymers. The model is based on an additive decomposition of the strain into four parts. Also, evolution laws for internal variables during both cooling and heating processes are proposed. Since temperature has considerable effect on the shape memory polymer behavior, for simulation of a shape memory polymer–based structure, it is required to perform a heat-transfer analysis. Commonly, an experimentally observed temperature rate–dependent behavior of shape memory polymers is justified by a rate-dependent glassy temperature, but using the heat-transfer analysis, it is shown that the glassy temperature could be considered as a constant material parameter. To this end, implementing the constitutive model within a nonlinear finite element code, we simulate torsion of a shape memory polymer rectangular bar and a circular tube. Moreover, we compare the predicted results with experimental data recently reported in the literature, which shows a good agreement.
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Shahidi, F., L. D. Wegner, and B. F. Sparling. "Investigation of bond between fibre-reinforced polymer bars and concrete under sustained loads." Canadian Journal of Civil Engineering 33, no. 11 (November 1, 2006): 1426–37. http://dx.doi.org/10.1139/l06-070.
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Although the use of fibre-reinforced polymer (FRP) bars to replace steel in reinforced concrete is becoming more common, uncertainty remains concerning the long-term performance of FRP, including the effect of a sustained load on the bond between the FRP bars and the concrete. An experimental study was therefore undertaken to investigate the long-term durability of the bond for various types of bars embedded in concrete: one type of glass FRP, two types of carbon FRP, and conventional steel reinforcing bars. Pullout specimens were tested both statically to failure and under sustained loads for periods of up to 1 year while free-end slip was monitored. Results revealed lower short-term bond strengths for FRP bars relative to steel and significant variability in long-term bond-slip performance among FRP bars of different types. Post-testing investigations revealed damage to bar surfaces at the macroscopic level, as well as broken longitudinal fibres and damage to the surface coatings at the microscopic level.Key words: reinforced concrete, fibre-reinforced polymer (FRP), bond, creep, pullout, sustained loads.
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Xu, Qin, Wei Huang, Hao Zhen Wu, Jun Yuan Wang, and Jie Yu Liu. "Study of Crack Width of the Fiber Reinforced Polymer Beam." Advanced Materials Research 243-249 (May 2011): 806–11. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.806.
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Fiber reinforced polymer (FRP) is a new kind of material for structural engineering in recent year. The partial inferiority of the bond and mechanical properties for FRP bars, however, leads to wider cracks compared with those of steel-reinforced concrete structures. Therefore, current design methods for predicting crack widths developed in concrete structures reinforced with steel bars at service load may not be used for concrete structures reinforced with FRP bars. This paper presents an analytical formula that calculates the maximum crack with in FRP- reinforced concrete beam, taking into account both the bond and the mechanical properties of FRP bars. The experimental results compared well with those proposed by the model.
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Voskobiynyk, S. P. "FIBRE-REINFORCED POLYMER BARS IN PRECAST SLABS FOR ROADS TO OIL AND GAS EXTRACTION COMPLEXES." ACADEMIC JOURNAL Series: Industrial Machine Building, Civil Engineering 1, no. 48 (March 27, 2017): 121–28. http://dx.doi.org/10.26906/znp.2017.48.785.
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Considered an example of the application of fibre-reinforced polymer bars in precast slabs for temporary roads to oil and gas extraction complexes. Found that samples of products by geometric requirements similar Ferro-concrete products, but reinforced fibre-reinforced polymer bars accessories instead of metal. The results of replacing metal fittings on the fibre-reinforced polymer bars in the experimental samples. Given the comparative assessment of the conformity of prototypes of requirements on indicates the ability and crack resistance from. Found that fibre-reinforced polymer bars valves may be used in the construction of a prefab temporary roads without reducing their carrying capacity. It is proven that the use of this rebar for reinforcement of structures that work on resilient basis, both at the stage of manufacture and operation. It is shown that the resulting experience can be used in the planning and in the design, manufacture and test prototypes, and the analysis of the obtained results allow you to identify opportunities for the implementation of this direction in Ukraine.
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Teng, Jin-Guang, Bing Zhang, Shishun Zhang, and Bing Fu. "Steel-free hybrid reinforcing bars for concrete structures." Advances in Structural Engineering 21, no. 16 (December 2018): 2617–22. http://dx.doi.org/10.1177/1369433218818772.
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Extensive research has been conducted on the replacement of steel rebars with fibre-reinforced polymer rebars to eliminate the steel corrosion problem in conventional steel bar–reinforced concrete structures. However, as the performance of fibre-reinforced polymer rebars is substantially inferior in compression (due to issues such as fibre micro-buckling) than in tension, their use in concrete columns is generally not recommended; this poses a significant challenge when a steel-free structure is needed. This article presents a novel steel-free hybrid rebar developed at The Hong Kong Polytechnic University that overcomes the above-mentioned problem. Such a hybrid rebar typically consists of a central fibre-reinforced polymer rebar, an external fibre-reinforced polymer confining tube and an annular layer of high-strength cementitious material such as ultrahigh-performance concrete. To demonstrate the performance of these hybrid rebars, results from a series of preliminary tests and associated modelling work are presented in the article. These results indicate that (1) the fibre-reinforced polymer rebar at the centre is well supported against bar buckling and fibre micro-buckling, (2) the compressive strength of the fibre-reinforced polymer material can be fully mobilized and (3) the stress–strain response of hybrid rebars can be designed to resemble an elastic–plastic response with some post-yielding hardening.
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Harrigan, John J., Bright Ahonsi, Elisavet Palamidi, and Steve R. Reid. "Experimental and numerical investigations on the use of polymer Hopkinson pressure bars." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372, no. 2023 (August 28, 2014): 20130201. http://dx.doi.org/10.1098/rsta.2013.0201.
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Split Hopkinson pressure bar (SHPB) testing has traditionally been carried out using metal bars. For testing low stiffness materials such as rubbers or low strength materials such as low density cellular solids considered primarily herein, there are many advantages to replacing the metal bars with polymer bars. An investigation of a number of aspects associated with the accuracy of SHPB testing of these materials is reported. Test data are used to provide qualitative comparisons of accuracy using different bar materials and wave-separation techniques. Sample results from SHPB tests are provided for balsa, Rohacell foam and hydroxyl-terminated polybutadiene. The techniques used are verified by finite-element (FE) analysis. Experimentally, the material properties of the bars are determined from impact tests in the form of a complex elastic modulus without curve fitting to a rheological model. For the simulations, a rheological model is used to define the bar properties by curve fitting to the experimentally derived properties. Wave propagation in a polymer bar owing to axial impact of a steel bearing ball is simulated. The results indicate that the strain histories can be used to determine accurately the viscoelastic properties of polymer bars. An FE model of the full viscoelastic SHPB set-up is then used to simulate tests on hyperelastic materials.
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Liu, Jianxun, Ning Li, Meirong Chen, Jianping Yang, Biao Long, and Zhishen Wu. "Durability of basalt fiber-reinforced polymer bars in wet-dry cycles alkali-salt corrosion." Science and Engineering of Composite Materials 26, no. 1 (January 28, 2019): 43–52. http://dx.doi.org/10.1515/secm-2018-0030.
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AbstractBasalt fiber-reinforced polymer (BFRP) bars have been increasingly applied to offshore structures, which are subjected to seawater corrosion and wet-dry cycles during their service time. This study evaluated the alkali-salt resistance performance of BFRP bars with different resin matrix types under wet-dry cycles. The tensile and shear strength of BFRP bars were tested. As a comparison, experiments of BFRP bars under continuous immersion were also conducted. The mechanisms of the two different conditions were analyzed by scanning electron microscopy (SEM). A relationship was established between the degradations under continuous immersion and wet-dry cycling. The results demonstrated that the alkali-salt resistance of vinyl resin matrix BFRP bars was superior to that of epoxy resin matrix BFRP bars under wet-dry cycles. Furthermore, according to the data obtained under continuous immersion, a time shift factor for predicting the durability of BFRP bars under wet-dry cycles was proposed.
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Fillmore, Brandon, and Pedram Sadeghian. "Contribution of longitudinal glass fiber-reinforced polymer bars in concrete cylinders under axial compression." Canadian Journal of Civil Engineering 45, no. 6 (June 2018): 458–68. http://dx.doi.org/10.1139/cjce-2017-0481.
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Contribution of longitudinal glass fiber-reinforced polymer (GFRP) bars in concrete columns under compression has been ignored by current design guidelines. This paper challenges this convention by testing 21 concrete cylinders (150 mm × 300 mm) reinforced with longitudinal GFRP and steel bars in compression. It was observed that GFRP bars could sustain high level of compressive strains long after the peak load of the specimens without any premature crushing. The results of a new coupon test method showed that the elastic modulus of GFRP bars in compression is slightly higher than that of in tension, however the compressive strength was obtained 67% of tensile strength. An analytical model was successfully implemented to predict the axial capacity of the tests specimens and it was found that the contribution of the bars in the load capacity of the specimens was within 4.5–18.4% proportional to the bars reinforcement ratio normalized to the elastic modulus of steel bars.
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Gribniak, Viktor, Aleksandr K. Arnautov, Gintaris Kaklauskas, Vytautas Tamulenas, Edgaras Timinskas, and Aleksandr Sokolov. "Investigation on application of basalt materials as reinforcement for flexural elements of concrete bridges." Baltic Journal of Road and Bridge Engineering 10, no. 3 (September 28, 2015): 201–6. http://dx.doi.org/10.3846/bjrbe.2015.25.
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Basalt polymers are rather new materials for civil engineering; therefore, identification of peculiarities and limitations of application of such polymers in concrete structures (particularly bridges) is of vital importance. This paper experimentally investigates deformation behaviour and cracking of flexural elements, which are predominant parameters governing serviceability of the bridges. Unlike a common practice, the present study is not limited by the analysis of concrete beams reinforced with the polymer bars; it also considers effectiveness of basalt fibre reinforced polymer sheets for repairing the beams. The analysis has revealed that a combination of the high strength and elasticity polymer materials governs the effective repair of the beams by significantly increasing (up to 40%) the structural stiffness.
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Semianiuk, Volha, and Viktar V. Tur. "Crack Resistance of the Self-Stressed Members Reinforced with FRP Bars." Solid State Phenomena 272 (February 2018): 244–49. http://dx.doi.org/10.4028/www.scientific.net/ssp.272.244.
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Fiber reinforced polymer (FRP) bars are widely used in building structures, especially that are exposed to the aggressive environment influence and other special conditions. Nevertheless, due to the low FRP (e.g. glass, basalt, aramid fibers reinforced polymers) bars modulus of elasticity, exceeding crack opening width, as well as deflections can be observed. FRP bars pretensioning is considered as an effective method of its structural performance increasing. Physico-chemical method of the FRP bars pretensioning based on the self-stressing concrete utilizing is an alternative to the mechanical method and in its turn doesn’t need for special devices and anchorage systems as well as qualified personnel. Assessment of the initial stress-strain state obtained during self-stressing concrete expansion stage in the reinforced self-stressed members is presented. Diagram method of the self-stressing parameters verification based on the static loading tests results is presented. Comparison of the initial stress-strain state obtained during concrete expansion stage and predicted by the proposed model, as well as assessment of its influence on the behavior at the static loading stage in cases of the self-stressed reinforced with FRP bars members and traditionally reinforced with steel bars self-stressed members was performed.
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Aly, Ragi. "Stress along tensile lap-spliced fibre reinforced polymer reinforcing bars in concrete." Canadian Journal of Civil Engineering 34, no. 9 (September 1, 2007): 1149–58. http://dx.doi.org/10.1139/l07-046.
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A theoretical study was carried out to investigate stress along tensile lap-spliced spaced or bundled fibre reinforced polymer (FRP) bars in concrete. R. Tepfers developed a mathematical model, which could be applied for any type of reinforcing bar, based on the modulus of displacement theory. The mathematical model can predict the bond stress and stresses in the reinforcing bars and the surrounding concrete. In this paper, the model developed by Tepfers was represented by applying the modulus of displacement theory, and theoretical predictions are compared with the experimental results from testing 16 large-scale concrete beams. Good agreement between the theoretical values and experimental results was observed at three stages of loading. Recommendations for investigating the modulus of displacement from pullout tests have been included. Lastly, the maximum average bond stress of spliced FRP bars can be estimated using the ultimate failure pattern analysis, in which the contributions of the splitting resistance were included.Key words: beams, fibre reinforced polymer (FRP) bars, bundled bars, concrete, tensile lap-splice, pullout tests, modulus of displacement, flexural tests.
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Benmokrane, Brahim, Hamdy M. Mohamed, and Ahmed H. Ali. "Service-life-prediction and field application of glass fiber-reinforced polymer tubular and solid bolts based on laboratory physical and mechanical assessment." Journal of Composite Materials 52, no. 24 (March 19, 2018): 3309–23. http://dx.doi.org/10.1177/0021998318764806.
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This paper presents the physical, mechanical, and durability characterization of glass fiber-reinforced polymer solid and tubular bars. These bars were subsequently used as rock bolts for ground control of the Jurong Rock Caverns in Singapore. The long-term performance of these bars was assessed under harsh environmental exposure (saline solution) simulating the subsea cavern water. The test parameters were (1) type of bars (solid and tubular), (2) temperature (20, 40, and 50℃), and (3) conditioning time (1000, 3000, and 5000 h). The measured tensile strengths of the bars before and after exposure were considered as a measure of the durability performance of the specimens and were used for long-term properties prediction based on a theoretical model. Moreover, microstructural analyzes using scanning electronic microscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry are also conducted to investigate the deterioration of fiber, matrix, and the fiber/matrix interface due to environmental conditioning. The results show the very high long-term durability of solid and tubular glass fiber-reinforced polymer rock bolts exposed to field conditions. The predicted tensile strength retention at a MAT of 32℃, with an RH of 100%, is 0.90 and 0.82 for a service life of 100 years for solid and tubular glass fiber-reinforced polymer bars, respectively. Based on the findings of this research, the tested glass fiber-reinforced polymer rock bolts were recommended as alternatives to stainless-steel rock bolts and successfully used as ground control in the Jurong Rock Caverns in Singapore.
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Garbacz, Andrzej, Marek Urbański, and Andrzej Łapko. "BFRP Bars as an Alternative Reinforcement of Concrete Structures - Compatibility and Adhesion Issues." Advanced Materials Research 1129 (November 2015): 233–41. http://dx.doi.org/10.4028/www.scientific.net/amr.1129.233.
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One of the most common causes of damage to concrete structures is the corrosion of the reinforcement. Reinforcement made from Fiber Reinforced Polymers (FRP) is considered as an attractive substitution of traditional steel reinforcement. A different technical characteristic of fiber reinforced polymer makes designing structures with FRP reinforcement differs from conventional reinforced concrete design. Therefore, it is necessary to identify the differences and limitations of their use in the concrete structures, taking into account their material and geometrical features. Basalt Fiber Reinforced Polymer (BFRP) is a relatively new material for reinforcing bars. On the basis of the ACI 440.1R-06 guidelines as well as experimental results for selected BFRP reinforced beams a model of compatibility in a system: BFRP bar - concrete was proposed. Additionally, based on the results of FEM simulations, the effect of BFRP bars ribbing on their adhesion to concrete was discussed.
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Othman, Zrar Sedeeq, and Ahmed Heidayet Mohammad. "Behaviour of Eccentric Concrete Columns Reinforced with Carbon Fibre-Reinforced Polymer Bars." Advances in Civil Engineering 2019 (July 22, 2019): 1–13. http://dx.doi.org/10.1155/2019/1769212.
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The use of steel bars as reinforcement is not preferred in some concrete structures because steel causes corrosion or electric magnetic field problems. One of the best alternatives to steel bars is carbon fibre-reinforced polymer (CFRP) bars. The experimental program consisted of 18 reinforced rectangular concrete columns under different eccentric loadings. Out of the 18 columns, 15 were reinforced with CFRP longitudinal rebars and ties and 3 were reinforced with conventional steel rebars and ties as reference columns. The following parameters were included in this study: the replacement of steel with CFRP bars, eccentricity of load, longitudinal reinforcement ratios, and tie spacing. Test results in terms of load-strain, load-mid height deflection curves, and crack patterns showed that the column reinforced with CFRP bars behaved similarly to the concrete column reinforced with conventional steel bars with a slight difference in axial and flexural capacity. The increment in CFRP longitudinal reinforcement ratios from 1.4% to 2.0% and 3.6% reasonably increased the maximum carrying capacity for different eccentricities used herein. The axial ratios of experimental to theoretical results (PExp./PTheor.) were determined for specimens in the present work and those from previous studies to assess the efficiency of the theoretical models.
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Semianiuk, Volha, and Viktar V. Tur. "Cracking and Failure Mode of the Self-Stressed Members with FRP Bars." Solid State Phenomena 292 (June 2019): 230–35. http://dx.doi.org/10.4028/www.scientific.net/ssp.292.230.
Full textAbstract:
Fiber reinforced polymer (FRP) bars represent a combination of the polymer binder and reinforcing fibers (glass, basalt, aramid, carbon). The main features of FRP bars are high tensile strength on the background of the relatively low elasticity modulus. To prevent development of the excessive both crack opening and deflections in the FRP reinforced concrete structures it can be effective to implement FRP reinforcement pretensioning with a limited level of created stresses. As a good option can be considered a physico-chemical method of FRP bars pretensioning based on the self-stressing concrete utilizing. In the self-stressed FRP reinforced members it is possible to obtain a considerable values of the early age restrained expansion strains (in comparison with steel reinforced self-stressed members because of FRP bars lower elasticity modulus), which will not disappear after air-dry shrinkage strains realization. In addition, another concern that have to be considered in the field of FRP reinforced self-stressed members is bond performance of the different FRP bars types, especially in combination with self-stressing concrete that within its expansion can provoke decompacting of the transit zone «bar-concrete». Moreover, taking into account that FRP bars is a composite material, its bond properties are strongly influenced by the types of the polymer binder, reinforcing fibers, ratio between binder and fibers, bar coating. Presented studies is consisted in the experimental investigations of the features in the crack development and depended on it occurred failure mode of the self-stressed members reinforced by the different types of FRP bars.
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Huang, Hui, Jie Lian, Jiaxing Li, Bin Jia, Dong Meng, and Zhizhong Wu. "Design and Evaluation of a New Resin-Filled GFRP Pipe Connection System for Butt Splicing of FRP Bars." Materials 14, no. 1 (December 31, 2020): 161. http://dx.doi.org/10.3390/ma14010161.
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Fiber-reinforced polymer (FRP) bars are one of the promising alternatives for steel bars used in concrete structures under corrosion or non-magnetic environments due to the unique physical properties of FRP materials. When compared with steel bars, FRP bars are difficult to be spliced in field application due to their anisotropy and low shear and compressive strengths. In view of this, the paper presents a new non-metallic connection system (i.e., resin-filled glass fiber-reinforced polymer (GFRP) pipe connection system) for the butt splicing of FRP bars. With the proposed connection system and a simplified trilinear interfacial bond-slip model, a set of design formulas were derived based on the requirement that the proposed connection system should provide a load transfer capacity beyond the tensile capacity of the spliced FRP bars (i.e., to fulfill the high tensile strength of FRP materials). Besides, considering the fabrication error-induced load transfer capacity reduction of the connection system in field application, a correction factor was introduced in the paper to compensate for the reduced load transfer capacity by increasing the FRP bar anchorage length. At last, to estimate the effectiveness of the proposed connection system and the derived design formulas, nine specimens were fabricated with a kind of commercially available basalt fiber-reinforced polymer (BFRP) bars and the designed connection system and tested under unidirectional tension to study their tensile performance. With the comparison between the tested and theoretical results, the effectiveness of the proposed connection system and the derived design formulas are verified.
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Wiater, Agnieszka, and Tomasz Siwowski. "Comparison of Tensile Properties of Glass Fibre Reinforced Polymer Rebars by Testing According to Various Standards." Materials 13, no. 18 (September 16, 2020): 4110. http://dx.doi.org/10.3390/ma13184110.
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The widespread use of glass fibre reinforced polymer (GFRP) bars in reinforced concrete (RC) elements has yet been limited due to the anisotropic and non-homogeneous material behaviour of GFRP. The material characteristics of GFRP bars from different manufacturers vary as a function of several factors. Several standards have developed various procedures to investigate the mechanical characteristics of GFRP bars, but universal methods to test different types and diameters of GFRP bars in tension have not been fully developed. Due to the lack of such a standardized test procedure, there are some doubts and gaps in terms of the behaviour of GFRP bars in tension, which has led to lack of reliable information on their tensile properties. The determination of tensile characteristics of GFRP bars, including the tensile strength, modulus of elasticity, and ultimate strain, according to various test standards, is the main subject of the paper. This paper reports test results for tensile characterization obtained on four types of GFRP bars from four manufacturers with six various diameters. Moreover, the study compares various test procedures according to seven standards to characterize the tensile properties of GFRP bars, to examine the proposed test procedures, and to reveal main differences.
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Hassan, T., A. Abdelrahman, G. Tadros, and S. Rizkalla. "Fibre reinforced polymer reinforcing bars for bridge decks." Canadian Journal of Civil Engineering 27, no. 5 (October 1, 2000): 839–49. http://dx.doi.org/10.1139/l99-098.
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This paper describes the behaviour of two full-scale models of a portion of highway bridge slab reinforced with fibre reinforced polymer (FRP) reinforcement. The first slab was reinforced totally with carbon FRP (CFRP), and the second slab was reinforced with hybrid glass FRP (GFRP) and steel reinforcement. The models were tested under static loading up to failure using a concentrated load acting on each span of the continuous slab and the two cantilevers to simulate the effect of a truck wheel load. Load-deflection behaviour, crack patterns, strain distribution, and failure mode are reported. The measured values are compared to values calculated using nonlinear finite element analysis model. The accuracy of the nonlinear finite element analysis is demonstrated using independent test results conducted by others. The analytical model is used to examine the influence of various parameters, including the type of reinforcement, boundary conditions, and reinforcement ratio. Based on serviceability and ultimate capacity requirements, reinforcement ratios for using CFRP and GFRP reinforcement for typical bridge deck slabs are recommended.Key words: bridges, deflection, FRP, reinforcement, concrete, punching, slabs, shear, finite element model, strain.
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Gooranorimi, Omid, Wimal Suaris, Edward Dauer, and Antonio Nanni. "Microstructural investigation of glass fiber reinforced polymer bars." Composites Part B: Engineering 110 (February 2017): 388–95. http://dx.doi.org/10.1016/j.compositesb.2016.11.029.
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Abdul Hadi, Siti Hajaratul Akma, Hilmi Mukhtar, Hafiz Abdul Mannan, and Thanabalan Murugesan. "Polyethersulfone/Polyvinyl Acetate Blend Membrane for CO2/CH4 Gas Separation." Applied Mechanics and Materials 754-755 (April 2015): 44–48. http://dx.doi.org/10.4028/www.scientific.net/amm.754-755.44.
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The synthesis of polyethersulfone (PES)/polyvinyl acetate (PVAc) blend membrane was successfully developed by dry phase inversion method. The membrane morphology characterized using Field Emission Electron Microscope (FESEM) showed both polymers were homogeneously mixed and a dense structure was formed. A shift in characteristic peak for most chemical groups was observed in blend membrane as analyzed by Fourier Transform Infrared (FTIR) analysis which suggests the presence of molecular interaction between the blend polymers. The permeability of carbon dioxide (CO2) and methane (CH4) gases was recorded at a constant pressure of 10 bars and room temperature. The permeability across polymer blend membrane showed better performance as compared with native polymer membrane.
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El-Salakawy, Ehab, Radhouane Masmoudi, Brahim Benmokrane, Frédéric Brière, and Gérard Desgagné. "Pendulum impacts into concrete bridge barriers reinforced with glass fibre reinforced polymer composite bars." Canadian Journal of Civil Engineering 31, no. 4 (August 1, 2004): 539–52. http://dx.doi.org/10.1139/l04-006.
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This paper presents the results of a pendulum impact test that was carried out on full-scale types PL-2 and PL-3 concrete bridge barriers reinforced with glass fibre reinforced polymer (GFRP) bars. A new corrosion-free connection between the barrier wall and the slab using GFRP bent bars was investigated. For comparison purposes, the impact test was also performed on identical concrete barriers reinforced with conventional steel. A total of eight full-scale 10-m-long barrier prototypes were constructed and tested. The tests included four PL-2 and four PL-3 prototypes. For each type of barrier, two prototypes were reinforced with GFRP sand-coated bars and the other two were reinforced with steel bars. Pendulum crash tests using a 3.0-t pear-shaped iron ball were performed under the same conditions for each type of barrier. The behaviour of the barriers was evaluated in terms of cracking pattern, crack width, and strains in reinforcing bars. The results of this investigation led to the conclusion that the behaviour of PL-2 and PL-3 concrete bridge barriers reinforced with GFRP bars is very similar to that of their counterparts reinforced with conventional steel in terms of cracking, energy absorption, and strength.Key words: concrete bridges, bridge barriers, glass FRP bars, impact, pendulum crash test.
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Ahmed, Ehab A., Christian Dulude, and Brahim Benmokrane. "Concrete bridge barriers reinforced with glass fibre-reinforced polymer: static tests and pendulum impacts." Canadian Journal of Civil Engineering 40, no. 11 (November 2013): 1050–59. http://dx.doi.org/10.1139/cjce-2013-0019.
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The behaviour of concrete bridge barriers reinforced with glass fibre-reinforced polymer (GFRP) bars has been investigated at the University of Sherbrooke in collaboration with the Ministry of Transportation of Quebec (MTQ) through a two-phase research project. This paper presents the test results of MTQ Type 311 barrier prototypes under static (Phase I) and pendulum impact (Phase II) loading conditions. The test program included two full-scale 2.6 m long barrier prototypes for laboratory testing under static loads (Phase I) and four full-scale 11 m long barrier prototypes for field impact tests (Phase II). The laboratory static tests included one prototype totally reinforced with GFRP bars and one totally reinforced with steel bars for comparison, whereas the pendulum impact tests included two replicas totally reinforced with GFRP bars and another two totally reinforced with conventional steel bars. The barrier walls of the six prototypes were provided with the same reinforcement amount of GFRP and steel bars (No. 20 GFRP @ 200 mm and 20M steel bars @ 200 mm). The performance of the GFRP-reinforced concrete (GFRP-RC) barriers was evaluated and compared with that of their steel-RC counterparts. The results of this investigation revealed that the behaviour of the GFRP-RC concrete bridge barriers of MTQ Type 311 is similar to their steel-RC counterparts.
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Esfahani, M. Reza, M. Reza Kianoush, and M. Lachemi. "Bond strength of glass fibre reinforced polymer reinforcing bars in normal and self-consolidating concrete." Canadian Journal of Civil Engineering 32, no. 3 (June 1, 2005): 553–60. http://dx.doi.org/10.1139/l05-005.
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This paper presents the results of an experimental study on bond strength of reinforcing bars made of glass fibre reinforced polymers (GFRP) embedded in normal and self-consolidating concrete. The study included pull-out tests of 36 GFRP reinforcing bars embedded in concrete specimens. Different parameters such as type of concrete, bar location, and cover thickness were considered as variables in different specimens. The results showed that the type of bond failure was by splitting of concrete for all specimens. The bond strength of bottom GFRP reinforcing bars was almost the same for both normal concrete and self-consolidating concrete. For the top bars, however, the bond strength of self-consolidating concrete was less than that of normal concrete.Key words: bond strength, glass FRP, reinforcing bars, top-bar effect, self-consolidating concrete.
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Liu, Zhi Yong, Lei Yu, Da Ji Li, and Kun Rong Wang. "Effect of Polymer Modified Cement-Based Coatings on Steel Bars Anticorrosion and Bond Properties between Coated Bars and Concrete." Applied Mechanics and Materials 368-370 (August 2013): 1066–69. http://dx.doi.org/10.4028/www.scientific.net/amm.368-370.1066.
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In this paper the anticorrosion properties of steel bars coated with polymer modified cement-based coatings in chloride solution were evaluated. Then the pullout tests were conducted using coated and uncoated steel bars embedded in concrete specimens and the bond properties between concrete and bars were tested. The results show the steel bars coated with epoxy emulsion modified cement-based coating (HY) and elastic copolymer emulsion modified cement-based coating (GT) have satisfactory anticorrosion properties in 3.5% NaCl solution for 96h. But the pullout tests display that the bond strength between the concrete and the steel bars coated with GT coating is much lower than that of the bars coated with HY coating and the uncoated specimens. The bond stress between the concrete and the bars coated with pure acrylate emulsion modified cement-based (CB) coating is the highest among the three coatings, but the resistance to chloride permeability of CB coating is poor. The results indicate the special epoxy-cement-based coating (HY) is more suitable for applying to the anticorrosion coating for steel bars in chloride condition.
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Bywalski, Czesław, Michał Drzazga, Maciej Kaźmierowski, and Mieczysław Kamiński. "Shear Behavior of Concrete Beams Reinforced with a New Type of Glass Fiber Reinforced Polymer Reinforcement: Experimental Study." Materials 13, no. 5 (March 5, 2020): 1159. http://dx.doi.org/10.3390/ma13051159.
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The article presents experimental tests of a new type of composite bar that has been used as shear reinforcement for concrete beams. In the case of shearing concrete beams reinforced with steel stirrups, according to the theory of plasticity, the plastic deformation of stirrups and stress redistribution in stirrups cut by a diagonal crack are permitted. Tensile composite reinforcement is characterized by linear-elastic behavior throughout the entire strength range. The most popular type of shear reinforcement is closed frame stirrups, and this type of Fiber Reinforced Polymer (FRP) shear reinforcement was the subject of research by other authors. In the case of FRP stirrups, rupture occurs rapidly without the shear reinforcement being able to redistribute stress. An attempt was made to introduce a quasi-plastic character into the mechanisms transferring shear by appropriately shaping the shear reinforcement. Experimental material tests covered the determination of the strength and deformability of straight Glass Fiber Reinforced Polymer (GFRP) bars and GFRP headed bars. Experimental studies of shear reinforced beams with GFRP stirrups and GFRP headed bars were carried out. This allowed a direct comparison of the shear behavior of beams reinforced with standard GFRP stirrups and a new type of shear reinforcement: GFRP headed bars. Experimental studies demonstrated that GFRP headed bars could be used as shear reinforcement in concrete beams. Unlike GFRP stirrups, these bars allow stress redistribution in bars cut by a diagonal crack.
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Kabashi, Naser, Arbër Këpuska, Enes Krasniqi, and Besart Avdyli. "Bond Coefficient kb of Concrete Beams Reinforced with GFRP, CFRP, and Steel Bars." Civil Engineering Journal 7, no. 7 (July 1, 2021): 1235–43. http://dx.doi.org/10.28991/cej-2021-03091722.
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There are several reasons why civil and structural engineers should use Fiber Reinforced Polymer bars in concrete. The primary reason is durability, and other relevant parameters, high strength and, lightweight. Non-corrosive attributes make their use particularly suitable in different situations. Due to low elastic modulus and poor bonding, the use of Fiber Reinforced Polymer results in larger crack widths under serviceability limit state especially beams reinforced with glass fiber bars. The study purpose of this paper is to investigate the kb values. The methodology of this paper is comparing the analytical and experimental results. The investigation included 12 beams, using the four-point load test. The geometrical parameters of tested beams with dimensions: 130×220×2200 mm, reinforced with different diameters, helically-grooved glass fiber bars, and sand-coated carbon fiber bars. The measured cracks were used to assess the current kb values recommended in the design codes and guides. The findings did not support the use of the same kb value for different bars because, in addition to the type of bar, the value of kb is also affected by the type of surface and the diameter of the bar. What is observed based on results shows that CFRP bars have a more constant value depending on the diameter, while GFRP bars have large value changes depending on the diameter. Doi: 10.28991/cej-2021-03091722 Full Text: PDF
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Vu, Dinh Tho, Elena Korol, Yuliya Kustikova, and Huy Hoang Nguyen. "Finite element analysis of three-layer concrete beam with composite reinforcement." E3S Web of Conferences 97 (2019): 02023. http://dx.doi.org/10.1051/e3sconf/20199702023.
Full textAbstract:
Reinforced concrete structures play an increasing important role in civil and industrial construction, along with the technology of new concrete materials and their calculation theories. In order to improve the crack resistance of three-layer reinforced concrete (3L-RC) beams with the middle layer of lightweight concrete (LWC) material, the method of using polymer bars in place of steel bars is applied. In this study, the behavior of 3L-RC beams with steel bars and glass fiber reinforced polymer (GFRP) bars is simulated and analyzed by ANSYS software (base on the finite element analysis). The simulation of reinforced concrete (RC) beam work on computer software is a modern method, which allows to input many mechanical, physical properties of materials and geometric parameters of 3L-RC beams. The results of the samples beam analysis showed that the cracking resistance of 3L-RC beams with GFRP bars have been enhanced more than twice compared to 3L-RC beams with steel bars. Numerical modeling allows comparison between the obtained results and building theoretical dependences in a wide range of specified parameters in sectional construction of multilayer reinforced concrete elements. This would limit the number of actual test samples, increase the efficiency of experiments.
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Zhao, Jun, Xin Luo, Zike Wang, Shuaikai Feng, Xinglong Gong, and Eskinder Desta Shumuye. "Experimental Study on Bond Performance of Carbon- and Glass-Fiber Reinforced Polymer (CFRP/GFRP) Bars and Steel Strands to Concrete." Materials 14, no. 5 (March 7, 2021): 1268. http://dx.doi.org/10.3390/ma14051268.
Full textAbstract:
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.
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Abed, Farid, Akrum Abdul-Latif, and Zin Mahaini. "Behavior of BFRP bars subjected to dynamic impact loads." MATEC Web of Conferences 304 (2019): 01011. http://dx.doi.org/10.1051/matecconf/201930401011.
Full textAbstract:
Fiber Reinforced Polymer (FRP) bars are deemed to be one of the best solutions to the corrosion dilemma associated with steel reinforcement. This paper presents an experimental study on the behavior of Basalt FRP bars subjected to impact loading. Dynamic tests were conducted on eighteen BFRP bars of 17 mm and 20 mm diameters (B17 and B20) using the drop hammer test procedure. Different loading rates were achieved through varying the weight of mass and height of fall. The paper evaluated the maximum stresses attained by the BFRP bars at various loading rates. As the loading rate increased, the B20 bars reported a higher strength value. However, the B17 bars showed a drop in the strength with the increase of the loading rate, which requires further investigation. The crushing was observed to be most prominent in the top part of the bars where the bars exhibited a conical shape after failure.