A report on fiber glass RC

1. ABSTRACT:
This document will address the use of fiber glass as an alternative for steel reinforcement in
concrete based building, show casing the physical, chemical and structural properties of fiber
glass reinforcement, and comparing them to commonly used black steel reinforcement.
THE USE OF GLASSFIBER–REINFORCED
CONCRETETURALMATERIAL
STRUCTURE 2

2. 1
THE USE OF GLASSFIBER–
REINFORCEDCONCRETETURAL
MATERIAL
STRUCTURE 2
1. INTRUDUCTION:
As the lack of steel resource and high cost of infrastructure
mount interest in corrosion-resistant reinforcement continually
grow, the need for a suitable and available substitute.
The potential for using a glass fiber reinforced concrete system
was recognized by Russians in the 1940s. The early work on
glass fiber reinforced concrete went through major modifications
over the next few decades. Many experiments on fiber
reinforced concrete with steel fibers and synthetic fibers have
Been conducted to obtain fundamental properties of mortar and
concrete reinforced with glass fibers, such as tensile and
compressive properties. Effect of fiber content on these
properties was examined and some problems were theoretically
discussed.
2. GFRC HISTORY AND APPLICATION
GFRC was originally developed in the 1940’s in Russia, but it
wasn’t until the 1970’s that the current form came into
widespread use.
Commercially, GFRC is used to make large, lightweight panels
that are often used as façades. These panels are considered
non-structural, in that they are designed to support their own
weight plus seismic and wind loadings, much in the way glass
window curtain walls are designed. The panels are considered
lightweight because of the thinness of the material, not because
GFRC concrete has a significantly lower density than normal
concrete. On average it weighs about the same as ordinary
concrete on a volume basis.
Façade panels are normally bonded to a structural steel frame
which supports the panel and provides connection points for
hanging.
GLASS FIBER
REINFORCED
CONCRETE
(GFRC)
Is a type of fiber reinforced
concrete, mainly used?
In exterior building facade
panels and as architectural
precast concrete.
Glass fiber reinforced
composite materials consist
of high strength glass fiber
embedded in a cementation
matrix. In this form, both
fibers and matrix retain their
physical and chemical
Identities, yet they produce
a combination of properties
that cannot be achieved
with either of the
components acting alone.

3. 2
3. GENERAL DATA AND FIBER TYPES
In order to make glass fibers resistant to the lime generated during the setting of Portland
cement, zirconium is added to the glass mixture composition prior to melting and fiberizing the
raw materials. The added zirconium becomes part of the glass fiber molecular structure in the
Manufacturing process i.e.; it is not just a protective coating. The minimum zirconium content in
the composition for good durability is about 16% by weight. The glass fibers with this zirconium
modification are usually referred to as alkali-resistant glass fibers or AR glass fibers. AR glass
fibers are chemically stable resisting both alkali and acid conditions. Chemical composition of
the AR glass fibers is shown in Table 1 and the physical and mechanical properties in Table 2.
Table 1- Chemical composition of AR-glass fibers,
percent by weight (PCI MNL-128-01)
Table 2- Properties AR-glass fibers (PCI MNL-128-01)
4. PRODUCTION OF GRC
Production of GRC with homogeneous characteristics requires a strict quality control, at the
production stage and in the final products. The European Standard EN 1169 or the International
Glass fiber Reinforced Concrete Association provide fundamental guidance and establish the
general rules for production of GRC.
There are two main production techniques of GRC.
4.1. Spray Up:
The mortar is produced separately from the fibers, which are mixed only at the jet of the
spray gun. The glass fiber strands are cut within the spray gun to the required size,
typically between 25 mm (0.98 inch) and 40 mm (1.57 inch), and are about 5% of the
GRC total weight. The subsequent compaction with a cylindrical roll guarantees the
adaptation of GRC to the form, the impregnation of the fibers within the mortar, the
removal of the air retained within the mix, and an adequate density.
Component AR-glass
SiO2 61.0-62.0
Na2O 14.8-15.0
CaO -
MgO -
K2O 0.0-2.0
Al2O3 0.0-0.8
Fe2O3 -
B2O3 -
ZrO2 16.7-20.0
TiO2 0.0-0.1
Li2O 0.0-1.0
Property AR-Glass
Specific Gravity 2.70-2.74
Tensile Strength, MPa [psi] 1700 [2.5 x 105]
Modulus of Elasticity, GPa [psi] 72 [10.4 x 106]
Strain at Break, % 2.0

4. 3
4.2. Pre-Mixture:
Mortar and precut fibers are previously mixed. The quantity of fibers added to the mortar
is usually up to 3.5%, in terms of weight, and the length of the fibers is around 12 mm
(0.47 inch). Longer fibers lead to an excessive reduction of the mix’s workability.
Production with premix GRC may involve several procedures such as injection and
vibration, pressing, or shotcreting.
5. STRUCTURAL PROPERTIES OF GFRC
GFRC derives its strength from a high dosage of AR glass fibers and a high dosage of acrylic
polymer. While compressive strength of GFRC can be quite high (due to low water to cement
ratios and high cement contents), it has very high flexural and tensile strength that makes it
superior to ordinary concrete. Essentially the high dose of fibers carries the tensile loads and
the high polymer content makes the concrete flexible without cracking.
6. ADVANTAGES OF GFRC
6.1. Lightweight
GFRC, thin yet strong, weighs 80% to 95% less than solid concrete. This makes it easier
and faster to install and reduces the load on the buildings structure. The lighter weight
and stronger material also save transport costs, allows more design freedom and, by
using less material, reduces environmental impact.
6.2. Superior Strength
GFRC is strong. For GFRC panels, this means it has the proven ability to withstand
seismic loads and hurricane winds. For architectural elements, stronger means less
chance for damage, easier to install and longer lasting.
6.3. Durable
GFRC lasts. It is less susceptible to weather erosion and more freeze thaw resistant
than conventional concrete. The use of glass fibers for reinforcement rather than steel
means it cannot rust and can even be used under salt water and in marine
environments.
6.4. Beautiful
GFRC provides the look and feel of natural stone, architectural precast concrete, terra
cotta, wood or smooth panels. It allows the designer more freedom in shape, color and
texture than any material.
6.5. Naturally Friendly to the Environment
GFRC has a much lower environmental impact than conventional concrete, stone or
other materials. Made with minerals: cement, aggregates, glass fibers and, in some

5. 4
cases mineral pigments and special polymers, GFRC is designed to be long lasting and
earth friendly.
7. DISADVANTAGES OF FIBERGLASS REINFORCED CONCRETE
7.1. Ductility
There is no ductility. Ductility is a solid material’s ability to deform under stress.
7.2. Cost
The cost of GFRC is higher than traditional concrete. Due to the fiberglass being inside
the concrete and the addition of additives and acrylic co-polymer the price is steeper.
7.3. Self-Mix
GFRC is difficult to self-mix. Generally, a contractor will mix and pour or spray this type
of concrete.
7.4. Workability
Greater reduction of workability.
8. COMPARISON BETWEEN BLACK STEEL AND (GFRP)
Black steel is inexpensive and commonly used. It’s a great reinforcement to use if you are not
responsible for the long-term maintenance of a concrete structure.
8.1. Tensile & Shear Properties
Tensile modulus 6 to 7.2 x 106 psi
Modulus of Elasticity > 8000 ksi
Compressive strength >60 ksi
Transverse Shear strength >20 ksi
Table 3- Mechanical Properties
8.2. Bond, CTE & Absorption
Bond strength* >1,200 psi / *Grit-Coat >2,200 psi
CTE :5.2x 10-6 IN. In./°C Specific gravity <2.0
Yield >100,000 psi Density <0.074 lb/in.3
Water absorption <0.25% Fiber Content >70%
Table 4- Corrosion Resistant Chart

6. 5
8.3. Fatigue
Bridge deck studies simulating heavy traffic over concrete
slabs have concluded that properly reinforced GFRP rebar
slabs
 Experience 2.5 times less cracking than steel
reinforced slabs
 Last 20 times longer than steel reinforced slabs
when exposed to heavy fatigue loads
Researchers believe that this is due to the differences in
the modulus of elasticity between GFRP and steel. GFRP
has a modulus very similar to concrete. Steel’s modulus is
many times higher. Steel is less forgiving than
GFRP. Damage occurs to concrete as steel bends within
the pour.
Table 5- Bridge Deck Slab Exposed To Cyclic Fatigue Loads
8.4. Cost
Cost Comparison GFRP to Plain Black Steel October 2009The largest price variance
between GFRP and black steel occurs when you compare the lowest grade black steel
to rebar GFRP rebar.
Depending on volume, a #3 10 mm plain black steel Grade 40 rebar can be 1/3 the cost
of a #3 10mm fiberglass rebar.
As the diameter of the bars increase this gap narrows to a point where a #8 22 mm plain
black steel bar is only slightly less expensive than #8 22 mm fiberglass rebar.
In some applications less concrete cover and reduced water proofing costs result in
lower initial project cost.

7. 6

8. 7
9. CONCLUSION:
Fiberglass rebar (GFRP) is a cost effective way to:
 Eliminate fundamental and expensive repair problems created by black steel
reinforcement.
 Maintain cosmetically attractive structures over time (less cracking and ugly rust
staining) resulting in higher property resale values.
 Reduce concrete cover and corrosion protection measures taken to protect black steel
rebar.
 Ensure your structures will last up to 4 times longer eliminating expensive capital
expenditures over time.
 Make slabs exposed to cyclic loads last 20 times longer than steel reinforced slabs.
 Fiber reinforcement is a common method to increase the mechanical properties of
materials.
 GFRC does not replace reinforced concrete when true load carrying capacity is required.
It’s best used for complex, three dimensional shells where loads are light.
 Generally fibers do not increase the flexural strength of concrete, and so cannot replace
moment resisting or structural steel reinforcement.
9.1. REFRENCES
 Introduction to GFRC (Glass Fiber Reinforced Concrete) / Jeffrey Girard
 GFRC – 30 Years of High Fiber Cement Composite Applications Worldwide / Graham T
Gilbert
 NRC Research Press / David T. Johnson and Shamim A. Sheikh
 Mechanical Properties of Glass Fiber Reinforced Concrete / Muna M .Abdullah & Eman
K.Jallo
 THE USE OF GLASS FIBER–REINFORCED CONCRETE AS A STRUCTURAL
MATERIAL / J.P.J.G. Ferreira and F.A.B. Branco
 Sustainable Concrete Solutions / FRP Distributors Inc.

9. 8
CONTENTS
Abstract:...................................................................................................................................................... 0
1. Intruduction: ......................................................................................................................................... 1
2. GFRC History and Application ............................................................................................................ 1
3. General Data and Fiber Types ............................................................................................................ 2
4. PRODUCTION OF GRC ..................................................................................................................... 2
4.1. Spray Up:...................................................................................................................................... 2
4.2. Pre-Mixture:.................................................................................................................................. 3
5. Structural Properties of GFRC ............................................................................................................ 3
6. Advantages of GFRC........................................................................................................................... 3
6.1. Lightweight ................................................................................................................................... 3
6.2. Superior Strength ......................................................................................................................... 3
6.3. Durable......................................................................................................................................... 3
6.4. Beautiful........................................................................................................................................ 3
6.5. Naturally Friendly to the Environment.......................................................................................... 3
7. Disadvantages of Fiberglass Reinforced Concrete ............................................................................ 4
7.1. Ductility......................................................................................................................................... 4
7.2. Cost.............................................................................................................................................. 4
7.3. Self-Mix......................................................................................................................................... 4
7.4. Workability.................................................................................................................................... 4
8. Comparison between Black Steel And (GFrp) .................................................................................... 4
8.1. Tensile & Shear Properties .......................................................................................................... 4
8.2. Bond, CTE & Absorption.............................................................................................................. 4
8.3. Fatigue.......................................................................................................................................... 5
8.4. Cost.............................................................................................................................................. 5
9. Conclusion:.......................................................................................................................................... 7
9.1. Refrences......................................................................................................................................... 7
Done By: Saad Dahleh