Strengthening of Reinforced Concrete Beams Using Bamboo Fiber/Epoxy Composite Plates in Flexure

2019 ◽  
Vol 821 ◽  
pp. 465-471 ◽  
Author(s):  
Siew Choo Chin ◽  
Jacky Neing Sheng Moh ◽  
Shu Ing Doh ◽  
Fadzil Mat Yahaya ◽  
Jolius Gimbun
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Composite Plate ◽  
Natural Fiber ◽  
Fiber Composite ◽  
Composite Plates ◽  
Bamboo Fiber ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Rc Beams

Fiber reinforced polymer (FRP) is widely used in the construction industry for structural strengthening due to their outstanding mechanical properties. However, the production of synthetic fibers such as FRP is detrimental to the environment. Alternatively, natural fiber composite may be used as external strengthening material. This paper presents the potential of bamboo fiber composite plate (BFCP) to strengthen the reinforced concrete (RC) beams in flexure. The bamboo of species Dendrocalamus asper was used to produce the fiber and fiber-to-volume ratio was set at 2:5. The composite plate was fabricated by binding bamboo fibers with epoxy using a hand-lay-up method. The flexural and tensile strength of the BFCP was measured and all the beams were tested to failure under four-point bending test. It was found that BFCP exhibited a higher flexural and tensile strength compared to pure epoxy samples. Meanwhile, the RC beams strengthened using BFCP exhibited an increment of 10-12% in beam structural capacity compared to the un-strengthened beams. Bonding of BFCP in the flexure zone was able to divert the vertical cracks into diagonal at the edge of the composite plate. Findings from this work may serve as a useful guide to strengthen RC beams using a BFCP.

scholarly journals Mechanical Behavior and Chloride Penetration of Precracked Reinforced Concrete Beams with Externally Bonded CFRP Exposed to Marine Environment

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Yan Xie ◽  
Kunhua Guan ◽  
Lei Zhan ◽  
Qichen Wang
Keyword(s):  
Reinforced Concrete ◽  
Marine Environment ◽  
Chloride Penetration ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Chloride Diffusion ◽  
Accelerated Ageing ◽  
Rc Beams ◽  
Cfrp Sheets ◽  
Externally Bonded

Cracked reinforced concrete (RC) beams can be repaired effectively by using externally bonded CFRP sheets. However, when the strengthened beams are subjected to marine environment, long-term performance will be affected by the material and the interface deterioration of concrete and CFRP. Therefore, to evaluate the service life of the strengthened beams, this study investigates the behavior of precracked RC beams strengthened with CFRP sheets exposed to marine environment. Accelerated ageing experiments were carried out by exposing specimens to cyclic wetting in sea water and drying in 40°C air for 3 months and 6 months, respectively. After the environment exposure, four-point bending test was conducted and then the diffusion of chlorides in the strengthened beams was analysed. The results show that the bonding behavior of the adhesive was weakened and the ductility of the strengthened beams was slightly reduced due to the marine environment. But there is no obvious strength difference between the strengthened beams suffered from marine environment for 3 months and 6 months. Besides, the precracks in the RC beams accelerated the chloride diffusion, while CFRP bonding reduced the chloride penetration. In addition, NEL method was employed to validate the effect of the cracks on chloride permeability. The results showed that the chloride diffusion coefficients increased with the depth of the cracks.

Potential External Strengthening of Reinforced Concrete Beam Using Natural Fiber Composite Plate

2018 ◽  
Vol 878 ◽  
pp. 41-48 ◽  
Author(s):  
Siew Choo Chin ◽  
Foo Sheng Tong ◽  
Shu Ing Doh ◽  
Jolius Gimbun ◽  
Yuen Kei Foo ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Natural Fiber ◽  
Fiber Composite ◽  
Volume Ratio ◽  
Physical And Mechanical Properties ◽  
Composite Plates ◽  
Reinforced Concrete Beam ◽  
Fiber Volume ◽  
External Strengthening

A study has been conducted to investigate the potential use of mengkuang leaves or Pandanus atrocarpus bonded with epoxy resin as external strengthening material for the strengthening of reinforced concrete (RC) beams. Physical and mechanical properties as well as structural properties of the mengkuang leaves-epoxy composite plates (MLECP) were evaluated in this study. Chemical treatment was performed on the dried mengkuang leaves using sodium hydroxide (NaOH) with concentrations of 2%, 5% and 8%. Scanning electron microscope (SEM) and flexural strength tests were conducted on the mengkuang leaves and flexural specimens, respectively. All the beams were tested to failure under four-point loading. Results showed that the flexural strength of the composite with 0.3 fiber volume ratio exhibited the highest flexural strength. Strengthening of RC beam using MLECP managed to increase the beam capacity.

scholarly journals Experimental assessment of the performance of reinforced concrete beams strengthened with carbon fiber reinforced polymer laminates

2020 ◽  
Vol 39 (1) ◽  
pp. 105-112
Author(s):  
N. Yusuf ◽  
J.M. Kaura ◽  
A. Ocholi ◽  
M. Abbas
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Rc Beams ◽  
Flexural Strengthening ◽  
Cfrp Laminates ◽  
Flexural Performance ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity

In this study, experimental research is carried out to assess the flexural performance of RC beams strengthened with different amount of CFRP laminates at the tension face. Twelve rectangular RC beams were fabricated and three are un-strengthened and used as reference beams and the remaining nine are strengthened with different amount of CFRP varying from single to triple layers and all are tested to failure under three points bending test. The increase of ultimate strength provided by the bonded CFRP laminates is assessed and failure modes is identified and compared to the un-strengthened RC beams. The results indicated that the flexural capacity of the beams was significantly improved as the amount of the laminates increases that ranged from 20% to 52% increased for single to triple layers laminates. It is concluded that the attachment of CFRP laminates has substantial influence on the performance of CFRP strengthened RC beams. Based on the observed results, recommendations are made that externally application of CFRP laminates can be used for a significant enhancement of the strength deficient RC beams in increasing the ultimate load carrying capacity. Keywords: CPRP laminate, Reinforced concrete, ductility, index, epoxy resin, flexural strengthening

scholarly journals External strengthening of reinforced concrete beam with opening by bamboo fiber reinforced composites

2020 ◽  
Vol 53 (6) ◽  
Author(s):  
Siew Choo Chin ◽  
Kong Fah Tee ◽  
Foo Sheng Tong ◽  
Shu Ing Doh ◽  
Jolius Gimbun
Keyword(s):  
Reinforced Concrete ◽  
Vinyl Ester ◽  
Fiber Composite ◽  
Bamboo Fiber ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Structural Behaviour ◽  
Fiber Volume ◽  
Shear Strengthening ◽  
Control Beam

AbstractThis paper presents the structural behaviour of reinforced concrete (RC) beams with and without openings strengthened externally with bamboo fiber reinforced composite (BFRC) plates in shear and flexure, respectively. Mechanical properties include tensile and flexural strength of epoxy, polyester and vinyl-ester based BFRC plates with 0%, 10%, 20%, 30% and 40% fiber volume fractions were evaluated. A total of fourteen beams were cast to evaluate the structural behaviour of RC beams strengthened with BFRC plates. All the beams were tested to failure under four-point bending. The results presented were in terms of load–deflection behaviour, failure mode and crack pattern. A comparison was also made between the performance of epoxy, polyester and vinyl-ester based BFRC plates in shear strengthening of RC beams with openings. Results revealed that the presence of openings in the shear zone reduced the original beam capacity of the control beam to about 52–55%. Shear strengthening of RC beams with openings using epoxy based BFRC plates showed significant improvement in regaining the beam structural capacity to approximately 32–36% higher than the un-strengthened beams. Meanwhile, strengthening of RC beams in flexure with epoxy based BFRC plates managed to regain the beam original capacity up to 98% of the control beam. Bamboo fiber composite reinforced with epoxy, polyester and vinyl-ester resins of 40% fiber volume fraction managed to regain the beam original capacity up to 82%. It was found that BFRC plates could divert and mitigate the formation of cracks away from the strengthened region as well as improved the beam ductility.

scholarly journals Stiffness and Strength Analysis of Flexural RC beams strengthened with CFRP Sheets Considering the Influence of Pre-cracking

Mechanika ◽  
2020 ◽  
Vol 26 (4) ◽  
pp. 277-284
Author(s):  
Tadas LISAUSKAS ◽  
Mindaugas AUGONIS ◽  
Tadas ZINGAILA ◽  
Mario Rui Tiago ARRUDA
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Experimental Program ◽  
Strength Analysis ◽  
Rc Beams ◽  
Cfrp Sheets ◽  
Good Agreement

                           This paper presents experimental, numerical and analytical analysis of newly cast and pre-cracking flexural reinforced concrete beams strengthened with CFRP. In total, 9 intermediate-scale composite beams were cast and tested using 4-point bending test setup. Midspan deflection, width of the cracks, concrete and CFRP strains were measured during the experimental program. Clear efficiency of composite pre-cracked beams was observed in comparison to newly cast beams: enhanced flexural capacity and increased stiffness after appearance of primary cracks in tension zone. Good agreement was found comparing experimental and theoretical (EC2) deflections of RC beams strengthened with CFRP. However, for more detailed verification, the analysis should be extended with more specimens. The shear stress at the end of CFRP sheets between the concrete and CFRP increased rapidly until reaching maximum slip value, when the reinforced concrete beam strengthened with CFRP reaches 60-90 % utilization of load bearing capacity. All experimental results were compared with numerical and analytical calculations. Experimental, numerical and analytical results were in sufficiently good agreement.

scholarly journals THE STUDY OF BENDING BEAMS MECHANICALS PROPERTIES WITH MICRO REINFORCEMENT

2021 ◽  
Vol 10 (2) ◽  
pp. 80-86
Author(s):  
Andi Yusra ◽  
Lissa Opirina ◽  
Teuku Farizal
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Natural Fibers ◽  
Reinforced Concrete Beam ◽  
Bamboo Fiber ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Fiber Concrete ◽  
Bamboo Fibers

research on fiber concrete is currently growing very rapidly. The alternative fibers used in the concrete mix-ture is to use natural fibers. In this study, researchers used bamboo fiber as a substitute for artificial fiber, where Bamboo has a good tensile strength. The aim of this study to increase beam strength in sustaining ex-ternal loads by added bamboo fibers. The content of fiber additional to the concrete mixture was 1.5% of the cement weight. The mix design of concrete using ratio of cement water 0.25. The plasticizer and filler added in the mixture with the content of 2% and 15% cement weight, respectively. Two reinforced concrete beam specimens and 24 concrete cylinder specimens used in the study. Tests carried out of 28 days, and 56 days for cylindrical concrete, while bending test conducted of CBR1 and CBR2 at 28 test life only. In study show that addition 1.5% bamboo fiber to reinforced concrete beams increased the flexural capacity and ductility of the beams

scholarly journals Structural Assessment of Reinforced Concrete Beams Incorporating Waste Plastic Straws

Environments ◽  
2020 ◽  
Vol 7 (11) ◽  
pp. 96
Author(s):  
Jamal M. Khatib ◽  
Ali Jahami ◽  
Adel Elkordi ◽  
Hakim Abdelgader ◽  
Mohammed Sonebi
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Split Tensile Strength ◽  
Waste Plastic ◽  
Three Point Bending ◽  
Ductility Index

The behavior of reinforced concrete beams containing fibers made of waste plastic straws (WPSs) under the three point bending test is examined. The effect of WPS fiber addition on the compressive and split tensile strength is reported. Four concrete mixes were prepared. The control mix PS-0 had a proportion of 1 cement: 1 sand: 2 coarse aggregate and a water cement ratio of 0.4. In the other three mixes PS-0.5, PS-1.5 and PS-3, 0%, 0.5%, 1.5% and 3% of WPS fiber (by volume) was added respectively. The results show that at 0.5% WPS, there is slight increase in compressive strength. However, beyond 0.5% addition, a decrease in compressive strength is observed. The split tensile strength shows a systematic increase with the addition of WPS fibers. The reinforced concrete beams containing WPS fibers show higher ductility as demonstrated by the larger ultimate tensile strain and ductility index (Δu/Δy). There is a tendency to have more fine cracks with the presence of WPS fibers.

scholarly journals Experimental study of RC beams strengthened for bending by reinforced grout layer and connectors

2018 ◽  
Vol 11 (4) ◽  
pp. 810-833
Author(s):  
J. H. CANAVAL ◽  
T. J. DA SILVA ◽  
A. C. SANTOS
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Beams ◽  
Point Load ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Experimental Program ◽  
Rc Beams

Abstract This work is based on an experimental investigation of reinforced concrete beams strengthened to flexure for wrapping applying a type of metallic connector in the bond substrate/groute. The experimental program consisted of 5 beams used for reference (without strengthening), 5 beams reinforced with surface brushed texture substrate and 5 beams with metal connectors bonded to the substrate. The beams were submitted to four-point load bending test. Initially with a partial loading, executed the strengthening and were finally tested until the break. The strengthening was made up by the increase by graute, on the sides and bottom of the beam and reinforcing. The applied force, the displacement, deformations in steel and in concrete were measured. The reference beams failure by flexing with the calculated charges. The bending strengthening proved efficient, increasing the bearing capacity in 44% and the failure was by shear in the stretch without strengthening. Beams with connectors the increase was higher.

scholarly journals Experimental study on flexural behaviour of reinforced concrete beams strengthened with passive and active CFRP strips using a novel anchorage system

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Bartosz Piątek ◽  
Tomasz Siwowski
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Full Range ◽  
Positive Influence ◽  
Reinforced Concrete Beams ◽  
The Novel ◽  
Rc Beams ◽  
Flexural Behaviour ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

AbstractThe paper presents the research on reinforced concrete (RC) beams strengthened with carbon fibre reinforced polymer (CFRP) strips with various configurations in terms of anchoring and tensioning. The five full-scale RC beams with the total length of 6.0 m were strengthened with passive strips, without and with mechanical anchorages at their ends, as well as with strips tensioned by the novel prestressing system with three various prestressing levels ranging from 30 to 50% of the CFRP tensile strength. All RC beams were tested under static flexural load up to failure and they were investigated in a full range of flexural behaviour, including the post-debonding phase. The main parameters considered in this study include the use of mechanical anchorages, the effect of tensioning the strips and the influence of the various prestressing levels. Several performance indicators have been established to evaluate the beams’ behaviour. The study revealed that the RC beams strengthened using tensioned CFRP strips exhibited a higher cracking, yielding and ultimate moments as compared to the beams with passively bonded CFRP strips. Moreover, increasing the beams’ prestressing level has a significant positive influence on the performance of strengthened beams. However, it did not affect the ultimate load-bearing capacity of the beams. The optimal prestressing level for the novel system has been determined as 60% of CFRP tensile strength.

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