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The Use of FRP Bars in Concrete

Conference Paper · June 2014

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 The Use of FRP Bars in Concrete

Ferhat Aydın

Sakarya University, Technology Faculty, Civil Engineering Department, 54187,

Sakarya, Turkey
ferhata@sakarya.edu.tr

ABSTRACT
The investigations on the technical development have been continuous on the new
methodology and construction materials following to the technological development in
the world. The weakness of classical construction materials can be overcome by using
new technological materials. Fiber Reinforced Polymer (FRP) with the use of rapidly
increasing in all areas. FRP has become more and more popular as construction material
in civil engineering due to its advantages of corrosion-resistance, high strength,
nonmagnetic, fatigue-resistance and so on. Glass fiber reinforced plastic (GFRP) are one
of these FRP types. GFRP bars are basically constituted of resin, continuous or chopped
fiber. They are manufactured by using various manufacturing methods. Pultrusion
process is a proven manufacturing method for obtaining lengths of high quality GFRP
that used in the construction as a primary or secondary load bearing elements. The
process became a competitive alternative to traditional structural materials. Also in this
study the use of GFRP bars and concrete adherence were investigated.

1. Introduction

Researchers investigate new material types and applications and try to produce new
designs to decrease these problems and to satisfy these demands. In recent times there has
been a growing interest in composite materials for civil engineering applications. Many
researchers have concentrated on composite materials and hybrid designs, which can be
considered as a derivative of these materials. Composite materials have required properties
and are preferred in a wide variety of fields including the construction sector. Fiber
Reinforced Plastic (FRP) composites are one of these composite types. These composite
materials have drawn considerable attention due to their superior mechanical strength,
lightweight structure, high corrosion resistance and high resistance to chemicals, electric
insulation, low density and high resistance/density ratio (Aydın 2012, Won et al. 2012,
Gonilha et al. 2013, He 2012).

In the field of concrete structures, extensive research work has been directed
toward the introduction of innovative FRP as reinforcement-bars (re-bars) within concrete
elements and as valid alternative to traditional steel re-bars. Recently, there has been a
rapid increase in the use of fiber-reinforced polymer bars substituting for conventional
steel bars for concrete structures. In addition, FRP bars have the advantages of high
strength and light weight, and a number of design guides and national standards have been
published to provide recommendations for the analysis, design, and construction of
concrete structures reinforced with FRP bars (Jun-Mo 2012, ACI 440 2006, CAN/CSA-
S6-02 2002, JSCEs 1997).
 Figure 1. FRP profiles

Steel and concrete are the most important construction materials. Many concrete
structures subjected to aggressive environment, such as bridge, dam and offshore exposed to
deicing salts, combinations of moisture, temperature and chlorides reduce the alkalinity of
the concrete and result in the corrosion of steel bars. In the last two decades, fiber reinforced
polymer bars have been introduced as a corrosion-free elements for reinforcing concrete
structures and to avoid of the degradation phenomena generally induced by oxidation and
corrosion of steel rebars (Mazaheripour 2013). The estimate of repair cost for existing
highway bridges in the USA is over $50 billion, and $1 to $3 trillion for all concrete
structures. In Europe, steel corrosion has been estimated to cost about $3 billion per year.
To address corrosion problems, professionals have turned to alternative metallic
reinforcement, such as epoxy-coated steel bars, cathodic protection, and increased concrete
cover thickness. While effective in some situations, such remedies may still be unable to
completely eliminate the problems of steel corrosion (ACI 440 2001 and Zhou 2003).

The most commonly used FRP re-bars within civil engineering applications are
made of GFRP, carbon- fibers (CFRP), aramid-fibers and (AFRP). Especially in aggressive
environments such as marine surroundings or in bridge decks requiring deicing salts due to
harsh climates, concrete alkalinity drastically reduces and, as a result, corrosion and
degradation of traditional steel re-bars significantly accelerate. Steel re-bars may interfere
with the electromagnetic field created by such devices and lead to a misinterpretation of
their results. Replacing steel with FRP overcomes all the above disadvantages. Indeed FRP
re-bars offer an outstanding combination of physical and chemical properties and, in many
situations, are much more competitive and convenient to be used than steel re-bars. They
also have a lower weight (which greatly reduces the costs of installation), and are magnetic-
permeable and non-corrosive. Moreover, FRP re-bars, especially GFRP, are non-conductive
for electricity, and this may be a further benefit if used as reinforcement in electric railways
or undergrounds where stray currents may cause serious damage to buried metallic objects
by electrolysis accelerating corrosion of metal objects in touch with the soil. Other
undoubted advantages are related to their higher tensile strength and fatigue resistance
compared to traditional steel rebars [Domenico 2014].
2. FRP Bars and Historical Development

FRP composites have been used on a limited basis in structural engineering for
almost 50 years for both new construction and for repair and rehabilitation of existing
structures. The use of FRP bars and grids for concrete is a growing segment of the
application of FRP composites in structural engineering for new construction. From 1950s
to the 1970s, a small number of feasibility studies were conducted to investigate the use of
small-diameter glass FRP rods (Nawy and Neuwerth 1977). In the early 1980s, glass
helical–strand deformed reinforcing bars were produced for structural engineering
applications (Pleimann 1991). These bars were used to build magnetic resonance imaging
facilities, due to their electromagnetic transparency, also these FRP bars were cost-
competitive with stainless steel bars, which were the only other alternative for this
application. Designs were performed by registered structural engineers using the working
stress design basis, and the buildings were constructed using conventional construction
technology. In the late 1980s, interest in the use of FRP rebars received a boost as attention
focused on ways to mitigate corrosion in steel-reinforced concrete structures exposed to the
elements, especially highway bridge decks. In the United States, International Grating, Inc.
developed a sand-coated glass fiber– reinforced bar that was used experimentally in a
number of bridge deck projects. This was followed in the 1990s by the development of
deformed FRP bars by Marshall Composites, Inc. A number of companies experimented
with FRP bars with helically wound spiral outer surfaces (Bank 2006) (see Figure 2).

Figure 2. FRP bars

Extensive research was conducted in the 1990s on the behavior of concrete beams
and slabs reinforced with various types of FRP bars (Daniali 1990; Faza 1990, Nanni, 1993;
Benmokrane et al. 1996). Studies were also conducted on the use of glass fiber pultruded
FRP gratings in reinforced concrete slabs (Bank and Xi 1993). ACI published its first
design guide, ACI 440.1R- 01, for FRP-reinforced concrete in 2001 (ACI 2001). The guide
was subse-quently revised in 2003 (ACI 440.1R-03 2003), and the current version, ACI
440.1R-06, was published in 2006 (ACI 2006). FRP bar properties were developed usage
areas has expanded present (Figure 3) [Bank 2006].
 Figure 3. FRP bar applications [aslanfrp.com 2014]

3. Experimental studies

GFRP materials’ physical and mechanical properties were determined by experimental

methods. The Physical and mechanical properties of FRP profiles in experiments which
used a high number of samples are presented in Table 3.

Table 1. Properties of GFRP

Properties Values

Specific Gravity 1.80

Young Modulus 30000 Mpa

Tensile Strength 550 Mpa

Poisson Ratio 0.34

Test results showed that the modulus of elasticity of the samples which were axial to
fiber direction was 30000 Mpa and that the tensile strength was 550 Mpa. The specific
gravity of FRP material was 1.82 and Poisson Ratio was 0,34.

FRP and steel tensile testing of samples comparison chart is shown in Figure 4.
 7000

6000

5000
Stress (kg/cm2)

4000
GFRP
3000
Steel
2000

1000

0
0 0,05 0,1 0,15 0,2
Strain

Figure 4. GFRP and Steel tensile chart.

FRP rebars and concrete adherence tests are performed. The experimental setup has
been established for this purpose (see Figure 5 and Figure 6).

Figure 5. The experimental setup

 Figure 6. Technical illustration of the experimental setup

Adhesion test chart obtained results of experiments is given in Figure 7.

3500

3000

2500
Stress ( N/mm² )

Sandy sample
2000

1500

1000
Normal sample
500

0
0 50 100 150 200 250 300
Deformation ( mm )

Figure 7. Normal and Sandy GFRP samples test in concrete

Concrete bond surfaces sandblasted samples compared to normal samples are greatly
increased over. Adherence stress is approximately doubled.

4. Conclusions

Based on these results, the following conclusions may be drawn:

  There are several structural advantages of use of GFRP bars in concrete, including.
High tensile strength, lightweight and non-corrosive properties the increase of the
flexural stiffness, reducing the structures deformability, and the increase of the
structures strength capacity.

 GFRP bars have strong resistance to corrosion. GFRP bars are increasingly used
instead of steel bars to solve corrosion problems in reinforced concrete structures.

 Sanded surface GFRP bars show better concrete adherence values than normal GFRP
bars. As a result of experimental studies concrete bond is increasing about twice in
sanded surface GFRP bars.

 Especially, FRP bars use in marine and coastal structures will be positive gains. FRP
bars has corrosion resistance and high-strength will be used in a safe manner for a
long time.

REFERENCES

ACI 440. (2001). “Guide for the design and construction of concrete reinforced with FRP
bars”, American Concrete Institute 1-10.
ACI 440.1R-03 (2003). “Guide for the Design and Construction of Concrete Reinforced
with FRP Bars”, ACI 440.1R-03, American Concrete Institute, Farmington Hills,
MI.
ACI Committee 440, (2006). “Guide for the design and construction of concrete
reinforced with FRP bars”, ACI 440.1R-06. Farmington Hills (MI): American
Concrete Institute.
Aydın, F. 2012. (2012). “Investigation of Flexural Behavior of GFRP-Concrete-Steel
Fiber Hybrid Beams”, International Construction Congress. 11-13 October
Isparta/ Turkey.
Bank, L. C., and Xi, Z. (1993). “Pultruded FRP grating reinforced concrete slabs, in
Fiber-Reinforced Plastic for Concrete Structures”, International Symposium (ed. A.
Nanni and C. W. Dolan), SP-138, American Concrete Institute, Farmington Hills,
MI, pp. 561–583
Bank, L.C., (2006). “Composites for Construction Structural Design with FRP Materials”,
Wiley, New Jersey.
Bemokrane, B., Chaallal, O. and Masmoudi, R. (1996). “Flexural response of concrete
beams reinforced with FRP reinforcing bars”, ACI Structural Journal, Vol. 93, No.
1, pp. 46-55.
CAN/CSA-S6-02, (2002). “Design and construction of building components with fibre
reinforced polymers”, CAN/CSA S806-02. Rexdale (Ont): Canadian Standards
Association.
Daniali, S. (1990). “Bond Strength of fiber reinforced plastic bars in concrete”,
Proceedings of the first Materials Engineering Congress, ASCE, Reston, pp. 501-
510.
Domenico D. De, A.A. Pisano, P. Fuschi, (2014). “A FE-based limit analysis approach for
concrete elements reinforced with FRP bars”, Composite Structures 107 594–603,
Faza, S. S., and GangaRao, H. V. S. (1990). “Bending and Bond Behavior of Concrete
Beams Reinforced with Plastic Rebars, Transportation Research Record 1290, pp.
185–193.
Gonilha, J.A, Correia J.R, Branco, F.A. (2013). “Dynamic response under pedestrian load
of a GFRP–SFRSCC hybrid footbridge prototype: experimental tests and
 numerical simulation”, Compos Struct; 95:453–63.
He, J., Liu Yuqing, Chen, A., Dai, L. (2012). “Experimental investigation of movable
hybrid GFRP and concrete bridge deck.” Constr Build Mater; 26:49–64.
Japan Society of Civil Engineers (JSCEs). (1997). “Recommendation for design and
construction of concrete structures using continuous fiber reinforcing material”. ls.
Concrete Engineering Series 23. Tokyo: Japan Society of Civil Engineers.
Jun-Mo Yang, Kyung-Hwan Min, Hyun-Oh Shin, Young-Soo Yoon (2012). “Effect of
steel and synthetic fibers on flexural behavior of high-strength concrete beams
reinforced with FRP bars”, Composites: Part B 43 1077–1086.
Mazaheripour H., Barros J.A.O., Sena J.M. Cruz, M. Pepe, Martinelli E. (2013).
“Experimental study on bond performance of GFRP bars in self-compacting steel
fiber reinforced concrete”, Composite Structures 95 202–212.
Pleimann, L. G. (1991). “Strength, modulus and bond of deformed FRP rods”, in
Advanced composites for Civil Engineering Structures, (ASCE), pp. 99-110.
Nanni, A. (1993). “Flexural behavior and design of reinforced concrete using FRP rods”,
Journal of Structural Engineering, Vol. 119, No. 11, pp. 3344–3359.
Nawy, E. G. and Neuwert, G. E. (1977). “Fiberglass reinforced concrete slab and beams”,
Journal of Structural Engineering, Vol. 103, No ST2, pp. 421-440.
Won J.P., Yoon Y.N., Hong B.T., Choi T.J., Lee S.J. (2012). “Durability characteristics of
nano-GFRP composite reinforcing bars for concrete structures in moist and
alkaline environments”. Compos Struct; 94:1236–42.
Z. Zhou, J.P. Ou, and B. Wang. (2003). “Smart FRP-OFGB bars and their application in
reinforced concrete beams”, Proceedings of the first international conference on
structural health monitoring and intelligent structure, 13-15, Nov., Tokyo, Japan:
861-866.
http://www.aslanfrp.com/Aslan100/Aslan100fiberglassrebar.html (2014).

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