Art-of-review on CFRP Wrapping to Strengthen Compressive and Flexural Behavior of Concrete

Art-of-review on CFRP Wrapping to Strengthen Compressive and Flexural Behavior of Concrete

Hemanth Kumar Reddy KommaRuben Nerella Sri Rama Chand Madduru 

Department of Civil Engineering, Vignan’s Foundation for Science, Technology & Research, Guntur 522213, India

Corresponding Author Email: 
kommahemanthreddy@gmail.com
Page: 
159-163
|
DOI: 
https://doi.org/10.18280/rcma.290305
Received: 
3 March 2019
|
Accepted: 
19 May 2019
|
Published: 
25 August 2019
| Citation

OPEN ACCESS

Abstract: 

Strengthening of reinforced concrete structures is given top priority in construction sector across the world. Ageing and load pattern changes will affect the stability of structure may be reduced. In this case, Fibre-Reinforced Polymer (FRP) materials are recognized as vital constituents to solve stability issues of the modern concrete structures. The purpose of present constructive studies of various techniques for FRP retrofit concrete structures because, the FRP material has improves the structural performance in terms of stability, stiffness, strength and durability such that the Fibre-Reinforced Polymers wrapping is one of the techniques to regain the strength of a concrete structures. By various researchers the different wrappings techniques are used to regain the strength and also enhanced the durability of the structure. This paper focuses mainly on various wrapping techniques of FRP sheets for external strengthening of RC structures such as reinforced circular columns, square beams, columns and column-beam joints.

Keywords: 

FRP beam, FRP column, fiber reinforced polymer (FRP), FRP sheets, FRP strength, CFRP wrapping techniques

1. Introduction

FRP is a material composite that is combined with two different materials namely strengthening fiber and polymer matrix. This Sophisticated composite material used extendedly at aviation, navy & car ventures amid from previous couple of decades (1960 onwards) because of their great designing parameters are high stiffness and strength, less density, high fatigue and damping continuance, low thermal conditions and so forth. Structural specialists and therefore the housing industry have started to comprehend the composites as capability of reinforcing materials for several issues identified with the disintegration of infrastructures.

Presently multi day's numerous nations, repair and retrofitting of existing structures have turned into a noteworthy piece of the development movement. The recovery of solid structures is twisting up continuously on account of the need to keep up and upgrade the immense manufactured condition obtained from the twentieth century. Over the latest two decades, there has been an extending energy for using FRP composites to restore and strengthen reinforced structures. The external wrapping of FRP sheets/fabrics is a standout amongst the best procedure. ACI Committee-503 guidelines have different recommendations of FRPC materials included for selection of polymer adhesives (Resigns) for concrete [1]. Rebar’s and structural shapes are first applications by using composites. Afterwards, FRPC laminates are used for bridge girders to strengthening of concrete by bonding them to the tension side face of girder [2]. Carbon Fiber / Aramid or Kevlar Fiber/ Basalt Fiber & Glass Fiber are using to increase or to regain the strength of concrete structures.

2. Structural Elements Repair and Rehabilitation

The dominant a part of restoration works contains rehabilitation of previously damaged structures damaged because of seismic activity and nature calamities. Strengthening of concrete structures is additionally needed because of a result by degradation issues which are arising from improper design methodologies, questionable quality of construction. Due to these circumstances the structural rehabilitation has received abundant attention over the past 20 years in the construction sector. For these recent attentions on FRP composites researchers tends to had given, experimental and analytical analysis that had demonstrated that the utilization of this composite materials for rehabilitation of old structural elements is more cost-effective and needs less efforts and duration than the standard construction techniques. So, by means of cost it is most effective than any other rehabilitation technique that is standard throughout the years. Composite materials were initially used for flexural strengthening of RC bridges and also reinforcement of RC columns and brick walls against at the time of seismic activity.

Figure 1. Retrofitting of concrete specimens

Table 1. Properties-fiber reinforced polymer composites [1]

Item

Carbon ®Ber

Aramid ®Ber

Glass ®Ber

Polyacrylic Nitril Carbon

Pitch-Carbon

Kevlar 49

@Twaron

TechNora

E-glass

Alkali-resistant

glass

High

strength

High-

Young's

modulus

Ordinary

High-

Young's

modulus

Tensile

strength (Mpa)

3430

2450±3920

764 ±980

2,940±3,430

2,744

3,430

3430±3528

1,764 ±3430

Young's

modulus (GPa)

196±235

343±637

37±39

392±784

127

72.5

72.5±73.5

68.6 ±74.5

Elongation (%)

1.3±1.8

0.4±0.8

2.1±2.5

0.4 ±1.5

2.3

4.6

4.8

2±3

Density

(Gm/cm3)

1.7±1.8

1.8±2.0

1.6 ±1.7

1.9±2.1

1.45

1.39

2.6

2.27

Diameter (mm)

5± 8

9±18

12

8±12

3. FRP Strengthened Concrete Beams

To increase in stiffness and strength for FRPC plate provided to a couple of components in tension and placed perpendicular to cracks tends [3-4]. The Glass fiber RC polymer composite (GFRP) gives almost 40 % strength improvement is feasible for RC beams, whereas around 200 % strength upgrade is accomplished with (CFRPC) [5]. CFRP plates which are externally bonded can be efficiently used to strengthen RC beams. In between FRP layers delamination is observed [6]. Perfect bonding between reinforcement and concrete-FRPC laminate is observed [7]. Considering the tension in between concrete and FRPC to examine functionality criteria [8]. It was examined that the repairing of bond failure zone to concrete confinement, leads to significant strength gain under flexural stiffness by cyclic loading [9]. Textile reinforced concrete (TRC) performs all around contrasted and CFRP and has subjectively comparative consequences for the general conduct of the repaired beams [10]. U-jacketing is reduced the shear failure of beams and tensile strains in stirrups [11].

Figure 2. Arrangements of strengthening of tested beams [4]

Figure 3. Typical FRP stress strain relationship for various fiber [3]

4. FRP Strengthened Concrete Columns

The ductility nature of concrete elements significantly improves the strength by confined wrapping [12]. Shape, size and length of the concrete elements were effect the behaviour of FRP confinement it is very effective when those corners radii would be round edged [13]. Bonding of both concrete and composite will be considerable change by adhesive nature of bonding agent [14]. Ductility of column elements of the structure improved [15]. Uniform stresses around the circular concrete of small-scale square concrete column [16]. Initial later stresses take time to start the intense internal cracking of confined concrete [17]. The hoop direction of fibers increased the stability for columns with a moderate to low slenderness ratio of (l < 40) [18]. Sustainable stress is formed at columns when subjected to eccentric axial loads [19]. For cyclic loading significant variation is seemed in the behaviour of FRP confined concrete when bars are unstable [20]. The FRP confined concrete repaired for corrosion damaged it not only give the strength and ductility it also slows down the percentage rate of the corrosion reactivity [21]. Orientations of fiber fabric wrapping with angles 45°, 0°, 90° and the variations in the layers count would be result the strength [22]. Natural-flax fabric reinforced epoxy polymer material increases in peak load and fracture energy by 6-layer and it is 374 % and 4660 % and also S.E.M analysis show perfect bonding between materials [23]. Elevated temperatures should result the stress parameters in between FRP and concrete [24]. Round edged concrete members will help to decreases the stresses at the corners [25].

5. FRP System for Beam Column Joints

Being lacking of stiffness in between beam –column joints it imperils the integrity of whole structure. Repairs with FRP will improve the stiffness and strength of joints that should be achieved by the brittle mode of failure to ductile [26]. Non ductile beam-column joint of composite laminate system the effective upgrade of shear [27]. With the employment of touch of composites Specimens, reinforced exploitation of CFRPs show stiffer behaviour than GFRP, Energy dissipation capability is inflated [28]. Seismic execution of the reinforced beam-column joints in terms of their physical phenomenon response, stiffness, and energy dissipation capability is assessed [29]. Considerable improve in the lateral strength moreover ductility by adding CFRP composites to the non-seismic specimen [30]. . Alternative modelling for the assessment of seismic retrofitting of joints are to be analysed by STM model [33]. Concrete surface grooving is the method to enhance the bonding of externally reinforced FRP technique [34] To improve the seismic performance and to retrieve the column beam failure mode the effective method is to implementing wrapping technique of FRP at potential hinge region [35].

Note: ① One layer of CFRP/GFRP L wrap at each corner. ② One layer of GFRP sheet around the column. ③ One layer of GFRP/CFRP sheet along beam axis. ④ One layer of GFRP U wrap. ⑤ Tyfo fiber anchors.

Figure 4. Typical rehabilitation of T-Beam [32]

Table 2. Overview on existing studies by different authors

S.No

Researcher

Wrapping Material

Loading Type

Result

1

Norris et al. [3]

CFRP sheets

Monotonic static loading

Obtained different strengths on different orientations

2

Buyle-Bodin et al. [6]

CFRP plates

Monotonically in four-point bending

De- lamination decreased by the thickness of layers

3

Yang et al. [8]

CFRP plates

Monotonic static loading

Concrete cover separation failure mode in FRP strengthened RC beams

4

Contamine et al. [10]

(TRC)& CFRP

Static load test

Both materials shows similar behaviour

5

Nguyen-Minh

and Rovňák [11]

GFF & CFF

Concentrated loads

Brittleness reduced at shear failure mode of beams

6

Saatcioglu

and Grira [12]

3 layers CFRP

Compression

Capable of sustaining axial strains in excess of 0.5 %

7

Yan [23]

(FFRP)

Uniaxial compression

Increases the fracture energy by 6-layer of FFRP

8

Soman et al. [25]

Glass Fiber

Concentric Uniaxial compression

Rounding the corners effected the load-carrying capacity of rectangular columns

9

Mukherjee and Joshi [28]

GFRP,CFRP sheets& CFRP

Axial load

Increase in its yield load and initial stiffness

10

Le-Trung et al. [30]

CFRP

Lateral cyclic loading

Seismic performance improved by fiber direction inclined at 45°

6. Conclusions

Use of FRP in civil construction both in retrofitting and repair has been checked. This study represents the experimental results from concrete structures such as reinforced circular columns, square beams, columns and column-beam joints. External strengthening by composite materials through confinement can upgrade remarkably by both strength and strain ductility subjected to cyclic loading. The strength of the existing concrete members is depended on many factors that to be fabric size, shape, and also the type and condition of the structure.

(1) For RC Beams wrapping or retrofitting with CFRP, GFRP sheets and laminates are strengthened the structure by taking different load conditions, when compared to normal RC Beams FRP Beams are tends to brittle failure due to sudden breakup of FRP sheets at ultimate load.

(2) For RC beams more than 70 % increase in the Torsional capacity of concrete beams by FRP wrapping.

(3) For Columns strength and deformation capacity under eccentric axial loads is improved, increases pressure, leads internal cracking on the axial stress develops in concrete.

(4) FRP jacketing increases the axial load capacity and also the ultimate concrete compressive strain. Round corners enhance the load-carrying capacity of the rectangular columns.

(5) For T-Beams by using Carbon Fiber Reinforced Plastic sheet orientation at an angle of 45° under lateral cyclic loading condition improves the seismic performance.

There are a few gaps which should be addressed. Experimental, analytical examinations are required to understand the behaviour of joints at beam-column from torsion, ductility. For durability point various temperature condition tests is required to break down the execution of concrete structures.

  References

[1] Uomoto, T., Mutsuyoshi, H., Katsuki, F., Misra, S. (2002). Use of fiber reinforced polymer composites as reinforcing material for concrete. Journal of Materials in Civil Engineering, 14(3): 191-202. http://dx.doi.org/10.1061/(ASCE)0899-1561(2002)14:3(191)

[2] Meier, U. (1992). Carbon fiber-reinforced polymers: Modern materials in bridge engineering. Structural Engineering International, 2(1): 7-12. https://doi.org/10.2749/101686692780617020

[3] Norris, T., Saadatmanesh, H., Ehsani, M.R. (1997). Shear and flexural strengthening of R/C beams with carbon fiber sheets. Journal of Structural Engineering, 123(7): 903-911. https://doi.org/10.1061/(asce)0733-9445(1997)123:7(903)

[4] Grace, N.F., Sayed, G.A., Soliman, A.K., Saleh, K.R. (1999). Strengthening reinforced concrete beams using fiber reinforced polymer (FRP) laminates. ACI Structural Journal, 188(8): 865-874.

[5] Heffernan, P.J., Erki, M.A. (1996). Equivalent capacity and efficiency of reinforced concrete beams strengthened with carbon fibre reinforced plastic sheets. Canadian Journal of Civil Engineering, 23(1): 21-29. https://doi.org/10.1139/l96-003

[6] Buyle-Bodin, F., David, E., Ragneau, E. (2002). Finite element modelling of flexural behaviour of externally bonded CFRP reinforced concrete structures. Engineering Structures, 24(11): 1423-1429. https://doi.org/10.1016/s0141-0296(02)00085-8

[7] Thomsen, H., Spacone, E., Limkatanyu, S., Camata, G. (2004). Failure mode analyses of reinforced concrete beams strengthened in flexure with externally bonded fiber-reinforced polymers. Journal of Composites for Construction, 8(2): 123-131. https://doi.org/10.1061/(asce)1090-0268(2004)8:2(123)

[8] Yang, Z.J., Chen, J.F., Proverbs, D. (2003). Finite element modelling of concrete cover separation failure in FRP plated RC beams. Construction and Building Materials, 17(1): 3-13. https://doi.org/10.1016/s0950-0618(02)00090-9

[9] Harajli, M.H. (2007). Cyclic response of concrete members with bond-damaged zones repaired using concrete confinement. Construction and Building Materials, 21(5): 937-951. https://doi.org/10.1016/j.conbuildmat.2006.05.002

[10] Contamine, R., Si Larbi, A., Hamelin, P. (2013). Identifying the contributing mechanisms of textile reinforced concrete (TRC) in the case of shear repairing damaged and reinforced concrete beams. Engineering Structures, 46: 447-458. https://doi.org/10.1016/j.engstruct.2012.07.024

[11] Nguyen-Minh, L., Rovňák, M. (2015). Size effect in uncracked and pre-cracked reinforced concrete beams shear-strengthened with composite jackets. Composites Part B: Engineering, 78: 361-376. https://doi.org/10.1016/j.compositesb.2015.02.035 

[12] Razvi, S., Saatcioglu, M. (1999). Confinement of reinforced concrete columns with welded wire fabric. ACI Structural Journal, 86(5): 615-623.

[13] Mirmiran, A., Shahawy, M., Samaan, M., Echary, H.E., Mastrapa, J.C., Pico, O. (1998). Effect of column parameters on FRP-confined concrete. Journal of Composites for Construction, 2(4): 175-185. https://doi.org/10.1061/(asce)1090-0268(1998)2:4(175) 

[14] Shahawy, M., Mirmiran, A., Beitelman, T. (2000). Tests and modeling of carbon-wrapped concrete columns. Composites Part B: Engineering, 31(6-7): 471-480. https://doi.org/10.1016/s1359-8368(00)00021-4 

[15] Ye, L.P., Zhang, K., Zhao, S.H., Feng, P. (2003). Experimental study on seismic strengthening of RC columns with wrapped CFRP sheets. Construction and Building Materials, 17(6-7): 499-506. https://doi.org/10.1016/s0950-0618(03)00047-3

[16] Ye, L.P., Zhang, K., Zhao, S.H., Feng, P. (2003). Experimental study on seismic strengthening of RC columns with wrapped CFRP sheets. Construction and Building Materials, 17(6-7): 499-506. https://doi.org/10.1016/s0950-0618(03)00047-3

[17] Yazdchi, K., Salehi, M. (2008). Me Chanics of Com Pos Ite Ma Te Rials, 44(5): 495-504.

[18] Tamuzs, V., Tepfers, R., Zile, E., Valdmanis, V. (2007). Stability of round concrete columns confined by composite wrappings. Mechanics of Composite Materials, 43(5): 445-452. https://doi.org/10.1007/s11029-007-0042-y 

[19] Bisby, L., Ranger, M. (2010). Axial-flexural interaction in circular FRP-confined reinforced concrete columns. Construction and Building Materials, 24(9): 1672-1681. https://doi.org/10.1016/j.conbuildmat.2010.02.024

[20] Rousakis, T.C., Karabinis, A.I. (2012). Adequately FRP confined reinforced concrete columns under axial compressive monotonic or cyclic loading. Materials and Structures, 45(7): 957-975. https://doi.org/10.1617/s11527-011-9810-1

[21] Parvin, A., Brighton, D. (2014). FRP composites strengthening of concrete columns under various loading conditions. Polymers, 6(4): 1040-1056. https://doi.org/10.3390/polym6041040

[22] Rahai, A., Akbarpour, H. (2014). Experimental investigation on rectangular RC columns strengthened with CFRP composites under axial load and biaxial bending. Composite Structures, 108: 538-546. https://doi.org/10.1016/j.compstruct.2013.09.015

[23] Yan, L. (2015). Plain concrete cylinders and beams externally strengthened with natural flax fabric reinforced epoxy composites. Materials and Structures, 49(6): 2083-2095. https://doi.org/10.1617/s11527-015-0635-1

[24] Al-Nimry, H.S., Ghanem, A.M. (2017). FRP confinement of heat-damaged circular RC columns. International Journal of Concrete Structures and Materials, 11(1): 115-133. https://doi.org/10.1007/s40069-016-0181-4

[25] Soman, M., Chandrakumar, C.R. (2018). Axial behaviour of glass fibre reinforced polymer-confined reinforced concrete short columns. Structural Engineering International, 28(1): 44-50. https://doi.org/10.1080/10168664.2018.1431422 

[26] Said, A.M., Nehdi, M.L. (2004). Use of FRP for RC frames in seismic zones: Part I. Evaluation of FRP beam-column joint rehabilitation techniques. Applied Composite Materials, 11(4): 205-226. https://doi.org/10.1023/b:acma.0000035462.41572 

[27] Ghobarah, A., Said, A.M. (2001). Seismic rehabilitation of beam-column joints using FRP laminates. Journal of Earthquake Engineering, 5(1): 113-129. https://doi.org/10.1080/13632460109350388

[28] Mukherjee, A., Joshi, M. (2005). FRPC reinforced concrete beam-column joints under cyclic excitation. Composite Structures, 70(2): 185-199. https://doi.org/10.1016/j.compstruct.2004.08.022 

[29] Li, B., Chua, H.Y.G. (2009). Seismic performance of strengthened reinforced concrete beam-column joints using FRP composites. Journal of Structural Engineering, 135(10): 1177-1190. https://doi.org/10.1061/(asce)0733-9445(2009)135:10(1177)

[30] Le-Trung, K., Lee, K., Lee, J., Lee, D.H., Woo, S. (2010). Experimental study of RC beam-column joints strengthened using CFRP composites. Composites Part B: Engineering, 41(1): 76-85. https://doi.org/10.1016/j.compositesb.2009.06.005  

[31] Parvin, A., Wu, S. (2008). Ply angle effect on fiber composite wrapped reinforced concrete beam-column connections under combined axial and cyclic loads. Composite Structures, 82(4): 532-538. https://doi.org/10.1016/j.compstruct.2007.02.004 

[32] Li, B., Kai, Q. (2011). Seismic behavior of reinforced concrete interior beam-wide column joints repaired using FRP. Journal of Composites for Construction, 15(3): 327-338. https://doi.org/10.1061/(asce)cc.1943-5614.0000163

[33] Okahashi, Y., Pantelides, C.P. (2017). Strut-and-tie model for interior RC beam-column joints with substandard details retrofitted with CFRP jackets. Composite Structures, 165: 1-8. https://doi.org/10.1016/j.compstruct.2017.01.004

[34] Hordijk, D.A., Luković, M. (Eds.). (2018). High tech concrete: Where technology and engineering meet. https://doi.org/10.1007/978-3-319-59471-2 

[35] Ma, C., Wang, D., Wang, Z. (2017). Seismic retrofitting of full-scale RC interior beam-column-slab subassemblies with CFRP wraps. Composite Structures, 159: 397-409. https://doi.org/10.1016/j.compstruct.2016.09.094