Fiber-reinforced polymers are furthermore referred to as materials known as composites. They are produced by a mixture of two or more basic or parent materials to make and form an enriched compound having upgraded properties. Generally, FRP materials contain high strength fibers as (carbon, glass, or aramid )with an enriched polymer resin(vinyl ester, epoxy or polyester thermosetting plastic..), whereas the enriched fibers act, as the key reinforcing element, where the polymer resin or polymer matrix works as a holding or binder which transfers loads between fibers and protects fibers.

1. Repair & Rehabilitation of Concrete Structures Using
FRP Composites
Presentation by: Parvez Ahmad Hashmat
Entry#: 2019CET2027
Submitted to: Associate Prof. SHASHANK BISHNOI
Indian Institute of Technology-Delhi- 2020

2. Objectives
The overall objectives of this term paper are:
• To introduce FRP composites as the most effective and modern
technique of repairing and strengthening RC structures in the civil
engineering industry.
• To understand the influence of FRPs on durability and increasing the
duration life of reinforced concrete structures.
• To know the impact of fibers on the tensile strength of reinforced
concrete components.
• To identify several environmental conditions affecting the behavior of
FRP composites with RC members.
• To review repair methods and identify preferred repair procedures.
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3. Introduction
Fiber-reinforced polymers are furthermore referred to materials known as composites.
They are produced by a mixture of two or more basic or parent materials to make and
form an enriched compound having upgraded properties.
Generally, FRP materials contain high strength fibers as (carbon, glass, or aramid )with
an enriched polymer resin(vinyl ester, epoxy or polyester thermosetting plastic..),
whereas the enriched fibers act, as the key reinforcing element, where the polymer
resin or polymer matrix works as a holding or binder which transfers loads between
fibers and protects fibers.
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4. Glass Fiber Reinforced Polymer
Mainly three types of FRPs are found in the industry as:
Aramid Fiber Reinforced Polymer
Carbon Fiber Reinforced Polymer
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5. Properties of Different FRP Types Compared with Steel
Looking above, it says that FRP composites have much higher modulus and resistance
to deformation than steel.
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6. Retrofitting
FRP is used to repair and strengthen structural components in case of load-bearing in
existing structures; this is called “retrofitting.”
This term is categorized into two types as:
 Strengthening: when a structure’s strength needs to be upgraded.
 Repairing: FRP composites are used to repair both present and damaged structures
as it was initially designed to manage its stability and load-bearing capacity.
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7. The Behavior of FRP Strengthening Applications in RC Structures
Flexural Strengthening Applications:
Attaching externally bonded FRP plates or strips on
plain or reinforced concrete beams can be enhanced
in flexure on the tension zone of the member, with
the direction of FRP materials parallel to high tensile
stresses.
Shear Strengthening Applications:
Using different techniques as side bonding, NSM
(Near-Surface Mounted), etc. The method of
attaching FRP plates or strips on reinforced concrete
beams can boost shear capability. Tests carried out
by Chajes et al. on beams, results concluded that
shear capability in those beams could rise to 150%.
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8. The Behavior of FRP Strengthening Applications in RC Structures
Axial Strengthening Applications:
To strengthen columns and bridge piers to prevent
them from post-earthquake events, so it is FRP usage
in recent ages. Which can be bonded externally as
sheets or as NSM as well. tests indicated that nearly
three times the ultimate strength raised then the
original capacity the columns had.
Torsion Strengthening Applications:
To strengthen members in case of torsion are the least
researched area and are limited. It is due to when
beams have enough shear reinforcement; therefore,
the influence of torsion is ignored.
Results from the tests on beams have shown that they
achieved a 50% rise in ultimate torsional strength.
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9. Performance of FRP Under Environmental Conditions
Moisture and Humidity
In the case wrapping fabrics on the total surface
of the component, water can collect between the
bond lines; caused debonding and flaking of FRP
therefore it’s suggested especially for flexural
strength of slabs or beams to make a gap for
water to transfer and evaporate. While in the
case of shear strength, the gap should be 300mm,
and for columns strength gap should be between
30mm-50mm.
In the above table for classes 0 and 1, the whole surface can
be wrapped, but for classes 2 and 3, the complete wrapping
must be prevented.
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10. Performance of FRP Under Environmental Conditions
Freeze-Thaw
Freeze-thaw refers to the quality of concrete
before applying FRP if there are cracks in
concrete, so bonding between concrete and
FRP may not be perfect and freezing of water
in these voids cause expansion and then
flaking of FRP.
So it is important to consider freeze-thaw
cycles effects on the strengthened structures.
As a structure in a saline environment
causes steel corrosion, which leads to cross-
section reduction, swelling, cracking, and
spalling, so for these adverse effects of the
saline environment, the application of FRP is
preferred. CFRP materials are sturdy against
acids, alkalis, and other organic solutions,
and besides, they aren’t deteriorated
considerably in a saline environment.
Acidity/ Alkalinity
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11. FRP Installation
1. Externally Bonded Repair Method (EBR):
Any damage as cover breakage of a member, spalling, or
roughness of the surface of the member should be repaired
before the installation of FRP composites
If a member endured corrosion damage, then the cover is
removed, and corroded bars are cleaned, and again the
cover should be repaired, and FRP is applied.
In case of cracks, if cracks are wider than 0.3mm, so they
must be sealed as the resin is injected into cracks.
Steps while applying FRP materials.
•Surface preparation
•Site preparation
•Wet layup
•Strip or sheet installation
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12. FRP Installation
Typical Wrapping Schemes of FRP
• U Wrapped
• Side Bonded
• Full Wrapping
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13. FRP Installation
2. NSM (Near Surface Mounted) Repair Method:
The following steps are taken in applying FRP strips or rods in the NSM method.
 Cutting grooves with a diamond saw on the cover of the member laterally on the tension zone.
 Grooves should be dried Using brushes and pressed air.
 Resin or Epoxy grout is inserted in the groove as a binder.
 The FRP reinforcement strip or bar is placed into the groove.
 Finally, the extra resin needed to worn and filled the remaining part of them.
The difference between externally bonded wrapping and NSM rebar repairing is studied by scholars
it was stated the repair with NSM showed greater load capacity and ductility. Further, the
externally bonded wrapping method specimen indicated better capability against crack formation
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14. Steps in NSM Method
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15. Conclusions
The review and information above clearly highlights
and demonstrating excellent strengthening properties
of FRPs for RC structures and can be used in various
construction applications.in fact, we can say that FRP
composites have transformed a traditional and
straightforward repair and design of RC structures in a
modern way.
The primary influence of FRP material is on existing
structures to prolong their service life.
FRP composites have also shown outstanding features
like resistance against corrosion, chemicals, and the
environmental condition, etc. according to the
composition of the material.
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16. References
1) Rasheed, H. A. (2015). Strengthening Design of Reinforced Concrete with FRP (second
edition ed.). (E. J. Barbero, Ed.) Kansas, USA: CRC Press Taylor & Francis Group.
2) Ning Zhuang a, H. D. (2018, September). Cracking behavior of reinforced concrete piles
externally bonded with FRP. Elsevier, 9.
3) M.Z. Nasar, ⁎. R. (2019, Aug). Fiber-reinforced polymer composites in strengthening
reinforced concrete. Elsevier, 20.
4) Masuelli, M. A. (2013, Feb). Introduction of Fibre-Reinforced Polymers − Polymers.
Reasearchgate, 39.
5) Nilanjan Tarafder1, Raipriti Swain. (2016, Dec). Durability and Case Study of Fiber Reinforced
Polymer (FRP). IOSR Journal of Mechanical and Civil Engineering, 10.
6) R. Brown, A. Shukla, and K.R. Natarajan. (2002). FIBER REINFORCEMENT OF CONCRETE
STRUCTURES. The University of Rhode Island. RHODE ISLAND: UNIVERSITY OF RHODE ISLAND.
7) Sheikh, S. A. (2001). Performance of concrete structures retrofitted with fiber-reinforced.
Elsevier, 11.
8) V.K.R. Kodur a,*, P.P. Bhatt b, M.Z. Naser. (2019). High-temperature properties of fiber-
reinforced polymers and fire. Elsevier, 14.
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17. Thank You