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Fiber reinforced self compacting concrete
1. FRESH AND HARDENED STATE PROPERTIES
OF FIBRE REINFORCED SELF COMPACTING
CONCRETE
RAMAVATH
ARTHIK SURAJ
RATHOD
2. • CONTENTS:
1.INTRODUCTION
2.SELF COMPACTING CONCRETE
3.FIBRE REINFORCED SELF
COMPACTING CONCRETE
4.FIBRES USED IN SCC
5.ADVANTAGES OF FIBRES
6.TESTS CONDUCTED ON SCC
7.METHODOLOGY
3. INTRODUCTION:
• Concrete is the most versatile construction
material used in material science and
construction technology, which is a
mixture of cement , coarse aggregate,
fine aggregate and water and admixtures if
required.
4. • Even though concrete has achieved
significant progress, it has its own
limitations, viz concrete cannot flow past
obstructions into nooks and crannies.
• Thorough compaction is essential for
achieving strength and durability of
concrete.
• Since concrete is not produced under ideal
conditions at site, we do often end up with
poor results such as honeycombs or voids
in structures.
5. SELF COMPACTING CONCRETE(SCC)
• To overcome the limitations of concrete,
self compacting concrete is introduced.
• Self compacting concrete is highly
flowable , non-segregating concrete that
can be spread into place ,without any
mechanical consolidation.
• Great advantage of self compacting
concrete is increase in workability and
durability when compared to ordinary
concrete.
6. Fibre reinforced self compacting concrete:
• Concrete containing dispersed randomly
oriented fibres in SCC is known as Fibre
reinforced self compacting concrete.
• Properties such as flexural strength and tensile
strength are improved by further addition of
fibres in SCC.
• Fibre reinforced self compacting concrete have
advantages of both SCC and fibres.
7. LITERATURE REVIEW:
S.No Title Author Conclusion
1 FIBRE
REINFORCED
SELF
COMPACTING
CONCRETE
RAGHU.H
SHEENA.S
PAI.B.H.V
-Steel and polypropylene fibres in SCC
shows excellent tensile strength ,flexural
strength,shock resistance,
fatigue resistance , ductility and crack
resistance.Hooked or Crimped steel fibres
are most effective in bonding.Optimum
replacement of cement by fly ash improves
fresh properties.
2 SELF
COMPACTING
CONCRETE :A
CONCRETE OF
NEXT DECADE
N R GAYWALA
D B RAIJIWALA
-Good finishes without compaction
-The maximum compressive , tensile and
flexural strength for SCC can be obtained
by addition of 15% of fly ash in mix as
compared to addition of 25%,35%,45%
and 55% cement replacement by fly ash.
3. SELF
COMPACTING
FIBRE
REINFORCED
CONCRETE
JAYANTH
CHAKRABORTY
SULAGNO
BANERJEE
-Glass fibres reduces cracks and improves
surface integrity and reduce
bleeding.Workability of SCC decreases
with increase in steel fibres and high
workability can be achieved by adding high
range water reducers.
8. Fibres used in self compacting concrete:
• Although SCC has advantages over ordinary
concrete, use of fibres in SCC helps in
strengthening various properties.
Various fibres used in SCC are:
1.Steel fibres
2.Glass fibres
3.Natural organic fibres.
4.Synthetic fibres
5.Carbon fibres
9. Types of fibres:
1.Steel fibres: They are used to enhance
mechanical properties and characteristics
of concrete such as toughness, ductility
and flexural strength.Cracks are arrested
due to dispersed fibres .Corrosion damage
and increased density are drawbacks
10. 2.Glass fibres (fiberglass):Glass fibres are
lightweight and extremely strong . Strength is 4
times higher than that of steel.The main two
problems are breakage of fibres and surface
degradation of glass by high alkalinity of
hydrated cement paste .But now alkali resistant
AR-glass fibres are used.Resistance to impact
and plastic shrinkage(during curing).
11. 3.Natural organic fibres:
• Chemically more inert than either steel or glass
fibres.High impact strength but undergo organic
decay.Low modulus of elasticity.The problem of
mixing and uniform dispersion may be solved
by adding a super plasticizer.
• Low amount of energy
required to extract these
fibres
Eg:bamboo,coconut and
jute fibres,horse hair
12. 4.Synthetic fibres:
Man made fibres from petrochemical and textile
industries.Reduce segregation and plastic
shrinkage.Increases fire resistance.High
tensile strength.Low modulus of elasticity.High
chemical resistance and high melting point.
13. 5.Carbon fibres:
Very high modulus of elasticity and flexural
strength. Expansive.
Strength and stiffness characteristics are
superior to those of steel.
14. OVERALL ADVANTAGES OF FIBRES:
Improved durability of structure.
Increased tensile and flexural strength.
Higher resistance to later cracking.
Reduced shrinkage of early age concrete.
Increased fire resistance of concrete.
Reduces the spalling of the reinforcement cover
and improves abrasion resistance.
Increase in energy absorption capacity.
High potential to deal with impact and impulsive
or dynamic loads.
15. Requirements:
• The workability of SCC is higher than the
highest class of consistence described within
EN 206 and can be characterised by the
following properties:
• Filling ability
• Passing ability
• Segregation Resistance.
• A concrete mix can only be classified as Self-
compacting concrete if the requirements for all
three characteristics are fulfilled.
16. Tests conducted on SCC:
1.Slump test by
abram’s cone
2.U-box test
( FRESH STATE TESTS (uses EFNARC specifications))
18. S.No Method Unit Property Minimum value Maximum value
1 Slump flow by
Abrams cone.
mm Filling ability 650 800
2 T50cm Slump
flow.
sec Filling ability 2 5
3 V-funnel sec Filling ability 6 12
4 L-box h2/h1 Passing
ability
0.8 1.0
5 U-box (h2-h1)
mm
Passing
ability
0 30
19. Hardened state tests:(IS 516-1959)
1.Compressive strength: Test for compressive
strength is carried out either on cube or cylinder
Cube of 15cm*15cm*15cm is casted and cure it
in water and respective 3,7,28 days strength
can be determined under CTM.
2.Split tensile strength test: It is necessary to
determine the tensile strength of
concrete to determine the load
at which the concrete members
may crack.
20. Cylinder of 15cm dia and length of 30cm is
casted and cure it for 28 days.
Tensile strength is determined under CTM.
The split is formed diagonally.
3.Flexure strength test: It is a measure of an
unreinforced concrete beam or slab to resist
failure in bending.Beam of size
10cm*10cm*50cm is arranged
as shown in fig and flexure
strength is determined.
21. Methodology:
-Trial mix proportion is to be determined and then
tested for fresh state properties for SCC(tests
specified by EFNARC).Then cubes , cylinders
and prisms of specified standard dimensions
are to be casted and cured in water then 7 day
and 28 day compressive ,flexural , tensile
strengths are to be determined for various
percentages of fibres by weight of cement or by
volume of concrete.
-An optimum amount of fibres for which desired
properties are achieved can be determined
from results.