Silica fume is a finely-divided mineral admixture that fills voids between cement particles, resulting in very dense concrete with high compressive strength and low permeability. It works by filling voids created by water in the concrete matrix through particle packing. Advantages include lower permeability, higher strength, improved durability, reduced alkali-silica reactivity, and improved resistance to attack. It is used to produce high strength, corrosion resistant, and abrasion resistant concrete, as well as products like sewer pipes.

1. Silica Fumes
. By
Moiz Tariq

2. Context
• Silica fume
 What is silica fume.
 How does silica fumes works in concrete ?
 Advantages of silica fumes.
 Uses of silica fumes.

3. What is Silica Fume ?
Silica Fume is a finely-divided mineral
admixture, available in both uncompact
and compacted forms . This ultra-fine
material will better fill voids between
cement particles and result in a very dense
concrete with higher compressive
strengths and extremely low permeability.

4. How does Silica Fume work in Concrete?
The second function silica fume
performs in cementitious compounds is
a physical one. Because silica fume is
100 to 150 times smaller than a cement
particle it can fill the voids created by
free water in the matrix. This function,
called particle packing,

5. Advantages of Silica Fume
• Lowers concrete permeability.
• Significantly increases concrete durability.
• Increases ultimate strength gain.
• Beneficial in all types of high strength concrete applications.
• Improves bond strength to steel.
• Significantly reduces alkali-silica reactivity.
• Provides excellent resistance to sulphate or seawater attack.
• Reduces steel corrosion.
• Improves freeze/thaw durability of concrete.

6. Uses of Silica Fume
For production of high strength concrete, corrosion-
resistant concrete, abrasion-resistant concrete, and
low permeability concrete. Used to make sewer and
manhole repair products. Reduces rebound in
shotcrete application.

7. What is Flyash ?
The finely divided residue resulting from
the combustion of ground or powdered
coal, which is transported from the firebox
through the boiler by flue gases.” Flyash is
a by-product of coal-fired electric
generating plants.

8. Use of Flyash
Flyash will typically
require an air
entraining agent to
be added.

9. What is Blast Furnace ?
• The purpose of a blast furnace is to reduce and
convert iron oxides into liquid iron called "hot
metal".
• The blast furnace is a huge, steel stack lined
with refractory brick.
• Iron ore, coke and limestone are put into the
top, and preheated air is blown into the bottom.