Composite Materials

1. 1
Gaziantep University
College of Engineering
Civil Engineering Department
REPORT ON
Application And Use of Fiber Steel
Submitted by
Mohammed Layth Abbas
Student No:201444956
Supervisor
Assoc.Prof. Erhan Güneyisi
CE 543
(composite Materials)

2. 2
FRC(Fiber Reinforced concrete)
Fiber Reinforced Concrete is a composite material consisting of
cement, aggregate and discontinues, discrete, uniformly dispersed
suitable fibers.
Why to use FRC
 Plain concrete is a brittle material with limited
ductility and low tensile strength and strain capacity.
Internal micro-cracks are present in that concrete.
Thus the concrete leads to heavy brittle fracture.
 The role of randomly distributed fibers is to bridge
across the cracks and to provide some post-cracking
ductility. If the fibers are sufficiently strong and
bonded to material then FRC will carry significant
stress over a relatively large strain capacity in the post
cracking stage.
 Fibers are usually used in concrete to control cracking
due to plastic shrinkage and to drying shrinkage. They
also reduce the permeability of concrete and thus
reduce bleeding of water.
 Fiber reinforced concrete is used when there is
requirement for elimination small cracks.
ADVANTAGES
 Very high compression strengh
 High tensile strength
 High elasticity modulus
 Ductile behavior
 High durability

3. 3
Classification of FRC
1. Steel Fiber Reinforced Concrete (SFRC)
2. Glass Fiber Reinforced Concrete (GFRC)
3. Synthetic Fiber Reinforced Concrete (SNFRC)
4. Natural Fiber Reinforced Concrete (NFRC)
5. Recently some new FRC named High Performance Fiber
Reinforced Concrete (HPFRC) and Ultra High Performance Fiber
Reinforced Concrete (UHPFRC) have introduced which shows
significant changes over plain concrete.
Steel Fiber Natural Fiber
Glass Fiber Synthetic Fiber
Steel fibers
Steel fibers used for reinforcing concrete are defined as short, discrete
length of steel having an aspect ratio (ratio of length to diameter) from
about 20 to 100 with any of several cross sections and that are sufficiently
small to be randomly dispersed in a unhardened concrete mixture using
usual mixing procedures.

4. 4
Composition of Steel Fiber
 The composition of steel fibers generally includes carbon steel
or stainless steel.
 The length dimension ranges from 6.4mm to 76mm while the
diameter ranges from 0.25mm to 0.75mm.
 The steel fibers are described by a convenient parameter
“Aspect Ratio”. The aspect ratio is determined by length to
diameter ratio. It varies from 20 to 100.
Mix design of SFRC
As per ACI 544.1R, the mixing proportion of materials for SFRC will be
as follows:
1½- in.
maximum sized
aggregate
¾- in. maximum
sized aggregate
3/8- in.
maximum sized
aggregate
Property
250-450300-550350-600Cement
(kg/m3)
0.35-0.550.35-0.50.35-0.45w/c ratio
40-5545-5545-60Percent of fine
to coarse
aggregate (%)
4-54-64-8Entrained Air
Content
(%)
Fiber Content, (% of total volume)
0.2-0.70.3-0.80.4-1.0Deformed
Fiber (%)
0.4-1.40.6-1.60.8-2.0Smooth
Fiber (%)

5. 5
Properties of Concrete Improved by Steel Fibers:
1. Compressive strength :
 In compression the ultimate strength is only slightly affected
by the presence of Steel Fibers.
 The presence of steel fibers increases compressive strength
from 0 to 15% for up to 2% of volume of fibers.
2. Tensile strength :
 In direct tension, the improvement in strength is reported
from 30-40% for addition up to 2% by total volume of
fibers.
 It is observed that the split tensile strength increases from
10-45% for addition up to 3% by total volume of fibers.
3. Flexural Strength:
 Increase in the flexural strength of SFRC is much greater
than in tension or compression because of ductile behavior.
 The changed elastic distribution is importantly plastic in the
tension zone and elastic in the compression zone, which
poses a shift of neutral axis towards the compression zone.
 It changes from 20-100% for addition up to 3% by total
volume of fibers.
4. Fatigue:
 For a given type of fiber there is a significant increase in
flexural fatigue strength with increasing percentage of steel
fibers. Almost 1 1/2 times increase in fatigue strength due to
the increasing use of steel fibers.
5. Impact:
 Under flexural impact loading, the peak load for SFRC is 40
percent higher than the normal concrete. So, increased use of
steel fibers increase the impact resistance of the concrete.

6. 6
Application And Use Of SFRC:
 SFRC has been tried on overlays of air-field, road
pavements, industrial floorings, bridge decks, canal lining,
explosive resistance structures, refractory linings etc.
 It can also be used for the fabrication of precast products like
pipes, boats, beams, stair case steps, wall panels, roof panels,
manhole covers etc.
 SFRC is also being tried for the manufacture of prefabricated
formwork molds of “U” shape for casting lintels and small
beams.
 Hydraulic structures.
 shotcrete,Thin sheets, shingles, roof tiles, prefabricated
shapes, panels, curtain walls, Slabs on grade, Composite
decks, Vaults, safes, Impact resisting structures.