Microsilica is a byproduct of producing silicon metal or ferrosilicon alloys. It consists primarily of amorphous silicon dioxide (SiO2), its average granule diameter is 0.15~0.20 μm,specific surface area is 15000~20000 m2/kg.Mainly used for high transparency, high resistance to tear silicone rubber, silicone grease, sealed packaging materials such as capacitors.

Main Properties

Very low permeability to chloride and water intrusion.

Extremely high electrical resistivity (20 to 100 times greater than ordinary concrete).

Increased abrasion resistance on decks, floors, highways and marine structures.

Superior resistance to chemical attack from chlorides, acids, nitrates and sulfates.

Application Area

1) Concrete or Shotcrete

• Increase its density and strength, improve the performance on its durability,

impact resistance, corrosion resistance, anti-permeability and frost resistance etc.

2) Refractory material & Ceramics material

• Greatly improve its density, strength and high temperature performance.

3) Cementitous Repair Products (Mortars & Grouts)

• Low permeability, increase resistance from chlorides, acids, nitrates and sulfate etc.

4) Oil Well Grouting

• Increase durability and compressive strength, decrease permeability, better control of gas leakage.

5) Concrete Tile, roofing & wallboard,panels

• Lightweight and improve the strength.

6) Polymers & rubber product

7) other application, such as waterglass industry, thermal insulation material etc.

1. Effects on Fresh Concrete

• It reduces segregation possibilities, so it can be used as pumping aid.
• It almost eliminates bleeding, consequently finishing work shall begin early.
• Workability and consistency of concrete decreases.

2. Effects on Hardened Concrete

• The addition of microsilica improves different aspects of hardened concrete which include:
• Compressive strength, hence flexural and tensile strength are improved as well.
• Bond strength
• Abrasion resistance
• Reduces permeability; therefore, it helps in protecting reinforcement steel from corrosion.
• Impact and cavitations resistance.
• Sulphate Resistance
• Heat Reduction
• Chemical Resistance

• Microsilica is a grey; nearly white to nearly black powder.
• Spherical particles less than 1mm in diameter.
• The bulk density of microsilica is based on the degree of densification and varies from 130 to 600 kg/m³.
• The specific gravity of microsilica ranges between 2.2 to 2.3

Advantages

1. Reduces thermal cracking caused by the heat of cement hydration.
2. Improves durability to attack by sulphate and acidic waters.
3. Reduces the early age temperature rise.
4. Silica fume is cheap; therefore, it is cost-effective.
5. It reduces the overall slab weight and cost
6. Addition of microsilica decreases efflorescence due to the refined pore structure and increased consumption of the calcium hydroxide.

Practical Use of Microsilica in Concrete

1. Silica Fume Waterproof Concrete
2. High Strength Concrete
3. Shotcrete
4. Specifying for Durability
5. It is used in elastomeric, polymer, refractory, ceramic and rubber applications.