This file describes that how the silica fume concrete works and its uses and defects in construction work.

1. SILICA FUME CONCRETE
PRESENTED BY,
D.SELVAGANESH,
A.R.BAWA ABUL HASSAN,
3rd YEAR, DEPARTMENT OF CIVIL,
FATIMA MICHAEL COLLEGE OF ENGINEERING AND
TECHNOLOGY,
MADURAI – 20.

2. CONTENTS
 Introduction to silica fume concrete.
 Function of silica fume in concrete.
 Chemical composition.
 Physical characteristics.
 Available forms of silica fume.
 Properties of fresh concrete while using the
silica fume.
 Properties of hardened concrete by the usage of
silica fume.
 Applications of silica fume concrete.
 Advantages of silica fume material.
 Conclusion.

3. SILICA FUME CONCRETE
 Silica fume is an artificial pozzolona
having high pozzolonic activity.
 It is a By- product from an electric
arc furnace used in manufacture of
silicon metal or silicon alloy.
 It has high silica content of more than
80%.
 It is an excellent for use as a portland
cement supplement.

4. SILICA FUME CONCRETE

5. FUNCTION OF SILICA FUME
 Silica fume works on Two levels.
 The hydration of Portland cement produces
many components, including silicate
hydrates(CSH) and calcium
hydroxide(CH).
 The silica fume is added to the CH for
produce the additional CSH to obtain a
very good compressive strength can exceed
15000 psi.
 The additional CSH produced by the silica
fume is more resistant to attack from
aggressive chemicals then the weaker CH.

6. CHEMICAL COMPOSITION
 Chemical composition depends on the product
being made by the furnace.
 Composition is also influenced by the furnace
design.
 It is mostly made of silica having percentage of
more than 80.
 The other chemical composition include
Fe2O3,Al2O3,Cao,Na2O,K2o in small
percentages.
 Unlike the other By- products like Fly Ash, Silica
fume from a single source has little or no
variation in chemical composition from one day
to another.

7. PHYSICAL CHARACTERISTICS
 It should be in premium white and
standard grey colors.
 The specific gravity of the silica fume
concrete is 2.2.
 Its specific surface area is to be 20,000
sq.meters / kg.
 Particle size is less than 1 micron with
average diameter of 0.1 micron.
 The shape of the particle is spherical.
 It should be in Amorphous in nature.

8. AVAILABLE FORMS IN
SILICA FUME CONCRETE
Undensified forms with a bulk
density 200 – 300 kg/m3.
Densified forms with a bulk
density 500 – 600 kg/m3.
Pelletised forms with a bulk
density 600 – 800 kg/m3.
Slurry form.

9. PROPERTIES OF FRESH CONCRETE
USING THE SILICA FUME
 WORKABILITY.
 BLEEDING AND SEGREGATION.
 SETTING TIME.
 PLASTIC SHRINKAGE.
PROPERTIES OF HARDENED
CONCRETE
DRYING SHRINKAGE.
CREEP.
STRENGTH.

10. PROPERTIES OF FRESH
CONCRETE USING SILIC FUME
WORKABILITY:
 Workability is reduced
 Water demand increases
in proportion to silica
fume added.
 Water demand is 1% for
every 1% of
replacement of cement.
 Lower slump and &
more cohesive mix.

11. BLEEDING AND SEGREGATION:
 Bleeding is reduced as silica fume
particles find their way between two
cement grains.
 Segregation is reduced as the concrete
mix is more cohesive due to increase in
number of solid to solid contact points.
 From the above two discussion we had
cleared that the silica fume reduce the
bleeding and segregation property of the
fresh concrete.

12. SETTING TIME
 Time results have shown that the initial
setting time and final setting time is not
greatly influenced.
 This increase may be 30 minutes or so.
PLASTIC SHRINKAGE
Fresh concrete is subjected to surface
cracking is known as plastic shrinkage.
Since the silica fume concrete show no
bleeding, fresh concrete is subjected to the
plastic shrinkage.
Precautions should be taken ass per normal
concrete.

13. PROPERTIES OF HARDENED
CONCRETE
DRYING SHRINKAGE:
 Drying shrinkage test by different
researcher show that the long time
shrinkage of concrete is not affected
significantly by the addition of silica fume
to the concrete.
CREEP:
 The creep of the concrete containing silica
fume will be lower than the corresponding
Portland cement concrete.

14. STRENGTH
Concrete containing silica fume
show outstanding performance in
development of strength.
Strength of 62 – 80 Mpa can be
easily achieved.
Silica fume forms backbone of
high performance concrete due to
early high strength properties.

15. APPLICATIONS
 It is used to construct a New TJ ORN
Bridge in sweeden which having the high
strength, workability, durability and free
from any deformations and cracks.
 Girders using silica fume concrete.
 It is mostly used in high rise structures to
increase the life time of the structure
without any affects.
 It is most widely used in important
structures which had a high strength
when compared with another.

16. HIGHRISE BUILDINGS USING
SILICA FUME
 Since 1990’s high rise
structures or buildings
uses the silica fume
content to yield the high
strength concrete , high
compression strength,
without affecting of
wind forces , high
abrasion resistance and
high corrosion
resistance.

17. GRIDERS REDUCED USING
SILICA FUME CONCRETE

18. NEW TJ ORN BRIDGE IN
SWEEDEN

19. ADVANTAGES OF SILICA
FUME CONCRETE
 High early compressive strength.
 High tensile flexural strength and
modulus of elasticity.
 Very low permeability to chloride and
water intrusion.
 High bond strength.
 High electrical resistivity and low
permeability.

20. CONCLUSION
 From the above discussions we have
conclude the points about silica fume
concrete.
 Silica fume can be used to manufacturing
of concrete of very high strength at early
age.
 Forms the backbone of modern day high
performance.
 Strengths upto 200 Mpa can be achieved
by using silica fume.