2. Introduction
▪ Fiber Reinforced Concrete can be defined as a
composite material consisting of mixtures of
cement, mortar or concrete and discontinuous,
discrete, uniformly dispersed suitable fibers.
▪ Continuous meshes, woven fabrics and long wires
or rods are not considered to be discrete fibers
3. Effect of fibers in Concrete
▪ They control plastic shrinkage cracking and drying
shrinkage cracking.
▪ They also lower the permeability of concrete and
thus reduce bleeding of water
▪ If the modulus of elasticity of the fiber is higher
than the matrix (concrete or mortar binder), they
help to carry the load by increasing the tensile
strength of the material.
▪ Some fibers reduce the strength of concrete
4. Necessity
▪ It increases the tensile strength of the concrete
▪ It reduce the air voids and water voids the inherent
porosity of gel
▪ It increases the durability of the concrete
▪ Fibers such as graphite and glass have excellent
resistance to creep.
▪ the addition of small, closely spaced and uniformly
dispersed fibers to concrete would act as crack
arrester and would substantially improve its static
and dynamic properties
5. Factors effecting properties
of FRC
▪ Relative fiber matrix
▪ Volume of fiber
▪ Aspect ratio of fiber
▪ Orientation of fiber
▪ Workability and compaction of concrete
▪ Size of coarse aggregate
▪ Mixing
7. Steel Fiber
Aspect ratio : 30 to
250
Diameters vary from
0.25 mm to 0.75 mm
Hooks are provided at
the ends to improve
bond with the matrix
8. Polypropylene Fiber
Cheapest &
abundantly available
resistant to most
chemical
High melting point
(about 165 degrees
centigrade)
volume fractions
between 0.5 to 15
commercially used in
concrete
9. Glass Fiber
Made up from 200-
400 individual
filaments
can be chopped into
various lengths, or
combined to make
cloth mat or tape
not possible to mix
more than about 2%
(by volume) of fibers
of a length of 25mm
by conventional
mixing techniques
11. Carbon fibers
very high modulus of
elasticity and flexural
strength
Expansive
strength & stiffness
characteristics have
been found to be
superior even to those
of steel
they are vulnerable to
damage than even
glass fiber and hence
are generally treated
with resign coating
13. Glass fibers
▪ Glass fiber is chemical inorganic fiber, obtained
from molten glass of a specific composition
▪ Glass fiber is made of natural materials, so that its
products are ecologically pure and not harmful to
human health
▪ High bending, pulling, and pressure resistance,
high temperature resistance, low hydroscopy,
resistance against chemical and biological
influences, comparatively low density
▪ Glass fiber products have excellent electronic,
heat, and sound insulation capacities
14. Glass fiber reinforced concrete
▪ GFRC is actually cement mortar with countless
strands of embedded glass fiber
▪ GFRC has a dramatically reduced ballistic debris
profile
▪ Fibers are the principal load-carrying members
15. Types of fibers
▪ A-glass (close to normal glass)
▪ C-glass (resist chemical attacks)
▪ E-glass (insulation to electricity)
▪ AE-glass (alkali resistance)
▪ S-glass (high strength fiber)
16. Properties of Glass fiber
▪ A high tensile strength (1700 N/mm^2)
▪ High modulus
▪ Impact Resistance
▪ Shear strength
▪ Water resistant
▪ Thermal conductivity
▪ Low thermal expansion
▪ Less creep with increase in time
▪ Light weight and Low density
▪ Resistance to corrosion and Fire endurance
▪ Resistance to cracks in concrete
17. Casting of GFRC
▪ Spray-Up (very strong GFRC due to the
high fiber load and long fiber length)
▪ Premix (less strength than spray-up)
▪ Hybrid
Spray-up GFRC
