What is Microsilica?
An ultra-fine pozzolan produced during silicon and ferrosilicon manufacturing.
Microsilica is an ultra-fine powder rich in silicon dioxide (SiO₂), produced during silicon and ferrosilicon manufacturing.
Due to its high pozzolanic reactivity and fine particle size, it reacts with calcium hydroxide to form additional C-S-H gel, significantly improving concrete properties.
Key Points
- Higher compressive and flexural strength
- Reduced permeability
- Enhanced durability
- Resistance to aggressive environments
Performance you can specify
High Strength Enhancement
Boosts compressive and flexural strength through additional C-S-H formation.
Reduced Permeability
Refines pore structure, drastically limiting fluid and chloride ingress.
Improved Durability
Resists sulphates, chlorides and other aggressive environments.
Reduced Heat of Hydration
Supports controlled temperature profiles in mass concrete pours.
Eco-Friendly Solution
By-product utilisation reduces cement demand and carbon footprint.
Superior Bond
Tighter aggregate–paste bond for a denser, more cohesive matrix.
Technical Specifications
Consistent chemistry and particle profile — batch after batch. Values below are indicative and may vary within specification limits.
| Parameter | ASTM C-1240 | IS 15388:2003 | Sio92 | Test Method |
|---|---|---|---|---|
| Appearance | Grey to Dark Grey Fine Powder | Grey Fine Powder | Grey to Dark Grey Ultra-Fine Powder | Visual Inspection |
| Silicon Dioxide (SiO₂) | ≥ 85% | ≥ 85% | ≥ 92% | ASTM C114 |
| Particle Size | Average: 0.1–0.3 μm | Average: 0.1–0.3 μm | Average: 0.1–0.2 μm | ISO 13320 |
| Specific Gravity | 2.2 – 2.3 | 2.0 – 2.2 | 2.2 – 2.3 | ASTM C188 |
| Moisture Content | < 3.0% | < 3.0% | < 2.0% | ASTM C311-07 |
| Loss on Ignition | < 5.0% | < 4.0% | < 3.5% | ASTM C311-07 |
| Pozzolanic Activity | > 110 | > 85 | > 115 | ASTM C311-07 |
| Chloride Content | ≤ 0.30% | ≤ 0.30% | ≤ 0.10% | ASTM C1152 |
| Bulk Density | 550 – 700 | 550 – 700 | 570 – 650 | BS 512 Pt 2:1995 |
| BET Surface Area | > 15 | > 15 | > 18 | ISO 9277 |
Full technical data sheet available on request.