This document discusses different types of fiber reinforced concrete, including slurry infiltrated fiber concrete (SIFCON) and slurry infiltrated mat concrete (SIMCON). SIFCON involves pre-placing dry fibers in a mold and infiltrating them with cement slurry, allowing for higher fiber volumes between 5-30% compared to 1-2% in traditional fiber reinforced concrete. SIMCON uses continuous fiber mats reinforced with cement slurry. SIMCON provides inherent strength from the fiber mat configuration and utilizes fibers with higher aspect ratios. Both SIFCON and SIMCON improve upon traditional fiber reinforced concrete in improving tensile and impact strengths.

1. LIGHT WEIGHT CONSTRUCTION
MATERIALS
THE NORTHCAP UNIVERSITY, GURGAON1
UNIT-1
LECTURE - 4
Brig. S.K. Sharma (Retd.)
Pro Vice Chancellor and Professor
Department of Civil Engineering,
The Northcap University, Gurgaon

2. INDEX
THE NORTHCAP UNIVERSITY, GURGAON2
FIBRE REINFORCED CONCRETE
 SLURRY INFILTRATED FIBER CONCRETES
(SIFCON)
 SLURRY INFILTRATED MAT CONCRETE (SIMCON)
 USES OF SIMCON
 PROPERTIES OF SIMCON
 SIFCON VS SIMCON

3. FIBRE REINFROCED CONCRETE
THE NORTHCAP UNIVERSITY, GURGAON3
The presence of microcracks at the mortar-aggregate
interface is responsible for the inherent weakness of pain
concrete. The weakness can be removed by inclusion of
fibers in the mix. The fibers help to transfer loads at the
internal microcracks. Such a concrete is called fiber-
reinforced concrete.
Thus, the fiber-reinforced concrete is a composite material
essentially consisting of conventional concrete or mortar
reinforced by fine fibers.
Video: YouTube Fiber Reinforced Concrete, 06:25

4. THE NORTHCAP UNIVERSITY, GURGAON4
The addition of small, closely spaced and uniformly
dispersed fibres to concrete would act as crack arrester
and substantially improve its static and dynamic properties.
This type of concrete is known as Fibre Reinforced
Concrete.
Fibre reinforced concrete can be defined as a composite
material consisting of mixtures of cement mortar or
concrete and discontinuous, discrete, uniformly dispersed
suitable fibres. Continuous meshes, woven fabrics and long
wires or rods are not considered to be discrete fibres.

5. DISCRETE FIBER REINFORCED CONCRETE
THE NORTHCAP UNIVERSITY, GURGAON5
As brought out above, in this system, the concrete is
reinforced by the random dispersal of short,
discontinuous and discrete fine fibers of specific
geometry.
The fibers can be imagined as an aggregate with an extreme
deviation in shape from the rounded smooth aggregate. The
fibers interlock and entangle around aggregate particles and
considerably reduce the workability, while the mix becomes
more cohesive and less prone to segregation.

6. THE NORTHCAP UNIVERSITY, GURGAON6
The fibers suitable for reinforcing the concrete have been
produced from steel, glass and organic polymers.
Naturally occurring asbestos fibers and vegetable fibers,
such as jute, are also used for reinforcement. Fibers are
available in different sizes and shapes.
They can be classified into two basic categories: Those
having a higher elastic modulus than concrete matrix called
hard intrusion. Those with lower elastic modulus called soft
intrusion.

7. DISCRETE FIBER REINFORCED CONCRETE
(CONTINUED..)
THE NORTHCAP UNIVERSITY, GURGAON7
In contrast to reinforcing bars in reinforced concrete which
are continuous and carefully placed in the structure to
optimize their performance, the fibers are dis-continuous and
are generally randomly distributed throughout the concrete
matrix. As result the reinforcing performance of steel fibers,
for example, is inferior to that of reinforcing bars.

8. THE NORTHCAP UNIVERSITY, GURGAON8
In addition, the fibers are likely to be considerably more
expensive than the conventional steel rods. Thus, fiber-
reinforced concrete is not likely to replace conventional
reinforced concrete. However, the addition of fibers in the
brittle cement and concrete matrices can offer a
convenient, practical and economical method of
overcoming their inherent deficiencies of poor tensile and
impact strengths, and enhances many of the structural
properties of the basic materials such as fracture
toughness.

9. DISCRETE FIBER REINFORCED CONCRETE
(CONTINUED..)
THE NORTHCAP UNIVERSITY, GURGAON9
Essentially, fibers act as crack arrestor restricting the
development of cracks and thus transforming an inherently
brittle matrix, i.e., Portland cement with its low tensile and
impact resistances, into a strong composite with superior
crack resistance, improved ductility and distinctive post-
cracking behavior prior to failure.
Uses: Steel fibers are probably the best suited for structural
applications. Due to superior properties like increased tensile
and bending strengths, improved ductility, resistance to
cracking high impact strength and toughness, spalling
resistance, and high energy in hydraulic structures, airfield
and highways pavements bridge decks, heavy duty
floors and tunnel linings.

10. SLURRY INFILTRATED FIBER
CONCRETES (SIFCON)
THE NORTHCAP UNIVERSITY, GURGAON10
In general, the superior toughness and energy absorption
properties of FRC in comparison to conventional concrete
improve, as volume fraction of fibers increases. Techniques
for achieving high fiber volumes include the strategy of pre-
placing dry fibers in the framework and infiltrating the bed
of fibers with a cementing slurry. This composite is called
slurry infiltrated fiber concrete(SIFCON).

11. THE NORTHCAP UNIVERSITY, GURGAON11
SIFCON was first developed in 1979 by Lankard Materials
Laboratory, Columbus, Ohio, USA, by incorporating large
amounts of steel fibers in steel fiber reinforced cement-
based composites.
SIFCON is similar to fiber reinforced concrete in that lends
significant tensile properties to the composite matrix. The
fiber volume fraction, Vf (volumetric percent of fibers), of
traditional fiber reinforced concrete is limited by the ability
to effectively mix the fibers into the fresh concrete. This
limits the fiber volume Vf to between 1% and 2%,
depending upon the type of fiber used and the required
workability of the mix. On the other hand, SIFCON
specimens are produced with Vr between 5% and 30%.
The fiber volume depends upon the fiber type, i.e. length
and diameter, and the vibration effort utilized to fill the form.
Smaller or shorter fibers will pack denser than longer fibers,
and higher fiber volumes can be achieved with added
vibration time.

12. THE NORTHCAP UNIVERSITY, GURGAON12
Placement of Steel fibers in a mold
The first step in the preparation of SIFCON

13. THE NORTHCAP UNIVERSITY, GURGAON13
Attention should be paid to the orientation of fibers. If fibers
are aligned along the diameter of the cylinder (Core) a much
higher compressive strength can be expected compared to a
cylinder in which fibers are aligned along the axis of the
cylinder. Actually, it is reported that specimens with fibers
perpendicular to loading axis may exhibit twice the strength
of specimens with fibers placed parallel to load direction,
Cylinders shown in the figure are cored vertically and
horizontally from a slab with horizontally placed steel fibers.

14. Fiber orientation and edge
effect in a molded SIFCON
cylinder specimen
Orientation of fiber in cored
SIFCON as influenced by the
coring direction with respect
to fiber placement direction
THE NORTHCAP UNIVERSITY, GURGAON14

15. SLURRY INFILTRATED MAT CONCRETE
(SIMCON)
THE NORTHCAP UNIVERSITY, GURGAON15
Recently, another form of slurry infiltrated fiber composite
called slurry infiltrated mat concrete (SIMCON) has been
developed. SIMCON is a new generation of high
performance fiber reinforced concrete (HPFRC) made by
infiltrating continuous steel fiber-mats with a specially
designed cement-based slurry. Thus, instead of reinforcing
concrete with steel bars, it is reinforced with sheets of
stainless steel fibers injected with a mixture of cement,
aggregates and water, called slurry.
Uses: Fiber mats (available in rolls) are shaped and
wrapped around existing columns and beams and injected
with concrete slurry for repairing or strengthening existing
structures. The mats are made of recycled stainless steel
fibers.

16. USES OF SIMCON
THE NORTHCAP UNIVERSITY, GURGAON16
SIMCON can be used in new construction or to reinforce
existing structures. In conventional concrete reinforcement
is designed to fail before the concrete and at failure large
slabs chunks of concrete break apart from the
reinforcement and fall from the structure.
In SIMCON at failure, the mass of fibers and concrete
does not collapse. Instead of large chunks breaking and
falling from a structure, the material crumbles into small
harmless flakes which pose little danger to people or
property below.
This controlled form of failure is a key advantage of
SIMCON.

17. PROPERTIES OF SIMCON
THE NORTHCAP UNIVERSITY, GURGAON17
The advantage of steel fiber mats over a large volume of
discrete fibers is that the mat with predecided configuration
provides inherent strength and can utilize fibers with much
higher aspect ratios. The fiber volume is less than half that
required for slurry infiltrated fiber concrete (SIFCON), while
achieving similar flexural strength and energy absorption
capacity. Since the mat is already in a pre-formed shape,
handling problems are minimized and balling does not
become a factor.
The superior performance of the SIMCON over SIFCON is
related to the bonding of the mat fibers in the composite
concrete. In SIFCON, the relatively short embedment
lengths of 25 mm fiber, results in fiber pullout as the
primary failure mode. In the SIMCON composites, the
failure mode comprises multiple cracks and ultimate failure
occurs through fiber breakage in the high tensile stress

18. SIFCON vs SIMCON
THE NORTHCAP UNIVERSITY, GURGAON18
SIMCON is also easier to handle and construct than with
SIFCON. SIMCON is also better suited for applications
where one dimension is much smaller than the remaining
two, such as bridge deck overlays.
On the other hand, SIFCON is better suited for three-
dimensional applications, such as zones of reinforcing bar
anchorage or of beam column joint.

19. THE NORTHCAP UNIVERSITY, GURGAON19
Thank you