Microsilica
is highly reactive pozzolanic material produced during the manufacture
of Ferrosilicon and Silicon Metal Alloys. 
It is formed by the condensation of vapour given off during
the smelting of coal, quartz, iron ore and other ingredients
in an electric arc furnace at around 2000°C.
Microsilica powder is composed of ultra-fine solid spherical
particles of amorphous silica each approximately 100 times smaller
than a cement grain.
Typical Physical Composition:
| |
OPC |
Microsilica |
GGBFS |
PFA |
Surface area
g/m2 |
360 - 500 |
19,000-23,000 |
300 - 500 |
300 - 600 |
| Specific Gravity |
3.12 |
2.10 |
2.90 |
2.30 |
| Bulk density kg/m3 |
1,300 - 1,400 |
300 - 650 |
1,000 - 1,200 |
1,000 |
 Markets / Applications
 Concrete
/ Cementitious
Microsilica will:
- - Reduce segregation and bleeding in fresh concrete
- - Increase comprehensive, tensile and flexural strength
throughout the
curing cycle
- - Replace up to 35% OPC in a mix
- - Greatly reduce the ingress of water-borne deleterious
chemicals
- - Reduce the penetration of gases and so reduce carbonation
- - Improve resistance to freeze/thaw cycles
- - Increase abrasion resistance
- - Minimise the risk of alkali/silica reaction
- - Increase workability for equivalent slump
- - Greatly decrease rebound during application of shotcrete
Refractory
| High Temperature: |
Microsilica reacts with alumina
forming mullite which gives a castable high strength at up
to 1700°C |
| Heat Up: |
Improved green strength |
| Flow: |
Reduced water demand when casting |
| Dense Castables: |
Void filling for density for lower permeability,
higher strength and higher thermal conductivity |
 Other
- - Casting
- - Insulation
- - Non cementitious building products
|
