92% Densified Silica Fume
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Densified Silica Fume
92% Densified Silica Fume
High-purity microsilica for high-strength, low-permeability concrete
92% densified silica fume — also known as microsilica, silica dust or condensed silica fume — is a dark grey, amorphous SiO₂ powder recovered from silicon-metal and ferrosilicon furnaces. With >92% SiO₂ and a sub-micron particle size, it packs into the voids between cement grains and turns free lime into additional C-S-H gel — the reason engineers specify it for high-strength concrete, refractory castables and oil-well cement.
Sichuan Ewende New Material Co., Ltd.
ISO 9001 / 14001 / 45001 · CNAS · IAF certifiedWhat it does for your mix
Six reasons engineers keep specifying 92% densified microsilica — and why the densified form behaves differently in the silo and in the mixer.
High purity — 92% SiO₂
A micro silica fume with 92% SiO₂ content, recovered from submerged-arc silicon and ferrosilicon furnaces — high pozzolanic activity without coarse contamination.
Genuinely densified
Compressed-air tumbling makes the particles collide and agglomerate, driving out surface gas and raising bulk density to 240–270 kg/m³ (up to 320 kg/m³).
Easier handling and storage
Against the undensified 92% grade, the densified powder is markedly more convenient to store, move and dose — less dusting, better flow out of the silo.
Improved use performance
Density is raised specifically to improve in-use performance: it disperses evenly through the mix for smoother placement and a more consistent pour.
Enhanced durability
Cuts permeability, so chloride attack on rebar, freeze-thaw cycling and chemical corrosion are all held back over the service life of the structure.
Lower freight cost per tonne
Densification exists first of all to cut transport cost — more SiO₂ per container, less dust, fewer truck movements for the same delivered tonnage.
92% Densified Silica Fume parameters
Produced in conformance with ASTM specifications. Quality is controlled and monitored through the entire production process to ensure it meets or exceeds specification requirements.
| SiO₂ content | >92%ASTM C1240 / EN 13263 / GB/T require ≥ 85% |
|---|---|
| Form | Densified92% undensified grade also available on request |
| Bulk density | 240–270 kg/m³, up to 320 kg/m³Loose bulk density, densified |
| pH value | 5 – 8.5 |
| Colour | Dark Grey |
| Loss on ignition | Reported on COAASTM C1240 limit ≤ 6% |
| Moisture content | Reported on COAASTM C1240 limit ≤ 3% |
| 45 μm sieve residue | Reported on COAASTM C1240 / CSA A23.5 limit ≤ 10% |
| Pozzolanic activity index, 7 d | Reported on COAASTM C1240 limit ≥ 105% |
| Mean particle size | Reported on COASub-micron powder · value per shipment |
| Specific surface area | Reported on COAEN 13263 band is 15–35 m²/g |
| Standards compliance | ASTM C1240 · EN 13263 · GB/T 18736 · GB/T 27690ISO 9001 |
View the full comparison — silica fume limits under 9 national standards
| Parameter | EuropeEN 13263 | NorwayNS 3045 | FranceNF P18-502 | AustraliaAS 3586 | United StatesASTM C1240 | CanadaCSA A23.5 | JapanJIS A6207 | ChinaGB/T 18736 | ChinaGB/T 27690 |
|---|---|---|---|---|---|---|---|---|---|
| SiO₂ (%) ≥ | 85 | 85 | 85 | 85 | 85 | 85 | 85 | 85 | 85 |
| SO₃ (%) < | 2 | — | 2.5 | 3 | — | 1 | 3 | — | — |
| Cl⁻ (%) < | 0.3 | Report | 0.2 | Report | — | — | 0.1 | 0.1 | 0.1 |
| CaO (%) < | 1 | 2 | — | — | — | — | 1 | — | — |
| MgO (%) < | — | — | — | — | — | — | 5 | — | — |
| Si (%) < | 0.4 | — | — | — | — | — | 0.4 | — | — |
| Na₂O + K₂O (%) < | — | — | 4 | — | — | — | — | — | 1.5 |
| C (%) < | — | — | 4 | — | — | — | — | — | — |
| Moisture content (%) < | — | — | — | 2 | 3 | — | 3 | 3 | 3 |
| Loss on ignition (%) < | 4 | 5 | — | 6 | 6 | 6 | 5 | 6 | 4 |
| Specific surface area (m²/g) | 15-35 | ≥12 | 20-35 | — | — | — | ≥15 | ≥15 | ≥15 |
| 45 μm sieve residue (%) < | — | — | — | — | 10 | 10 | — | 5 | — |
| Bulk density (kg/m³) | — | — | — | Report | Report | — | — | — | — |
| Specific gravity (g/cm³) | — | — | 2.1-2.3 | — | — | — | Report | — | — |
| Water demand ratio (%) ≤ | — | — | — | — | — | — | — | 125 | 125 |
| Pozzolanic activity index, 3 d (%) ≥ | — | — | — | — | — | — | — | — | — |
| Pozzolanic activity index, 7 d (%) ≥ | — | — | — | Report | 105 | 85 | 85 | 95 | 105 |
| Pozzolanic activity index, 28 d (%) ≥ | 100 | 95 | — | — | — | — | 100 | 115 | — |
| Water / binder ratio | 0.5 | 0.5 | — | — | 0.484 | — | 0.5 | 0.5 | 0.5 |
| Curing regime | Standard | Standard | — | — | Accelerated | Accelerated | Standard | Standard | Accelerated |
Limits shown are the specification requirements of each national standard, for reference only. Actual values for each shipment are reported on the Certificate of Analysis.
How to dose it on site
Five practical notes that decide whether 92% densified microsilica performs — dosage band, admixture pairing, mixing time and curing.
-
1
In high-strength, high abrasion resistance and anti-washout underwater concrete, the dosage should not be too low — usually 5%–10% of the cementitious material.
-
2
Using Ewende 92% Densified Silica Fume for high-strength or early-strength concrete requires a high-efficiency water reducing agent; for high-strength concrete choose a low-air-entraining type, and add a defoamer where the situation calls for it.
-
3
In ordinary strength, impermeable, highly durable or self-compacting concrete, a multi-component cementitious material with a lower dosage is appropriate — usually 2%–5% of the cementitious material.
-
4
Adding 92% Densified Silica Fume needs a longer mixing time, and it must not be added to concrete that has already been wetted. Extend mixing by about 30 seconds versus ordinary concrete to ensure uniform dispersion.
-
5
The mix is sensitive to plastic shrinkage cracking. Spray a curing agent on shotcrete before it sets; once the concrete has hardened, use curing film and cover with wet sacks or plastic sheet.
Where 92% densified microsilica is used
From tunnel linings and refractory castables to oil-well cement — the same pozzolanic reaction, solving very different problems on site.
Silica fume for shotcrete
High resistivity and low permeability reduce chloride corrosion of rebar and mesh, cut rebound, and improve freeze-thaw durability — with better flexural and compressive strength.
Refractories
Binder, activator and mineraliser for refractory castables and kiln furniture — improves sintering density and crystal transformation.
Insulation material
The base raw material for composite silicate insulation coatings and boards.
PHC pipe pile
Enables non-autoclaved, energy-saving production while cutting coal, power and CO₂ output.
Oil well cement
Improves thermal stability and lowers permeability of the cement sheath around the casing.
Packaging
Palletized Small Bags
25kg soluble paper bags, 42 per pallet — space-saving, forklift-friendly and fast to load into containers.
Palletized & Stretch-Wrapped
Pallets secured with stretch film for safe loading, unloading and long-distance ocean shipping.
Kraft Paper Bags
25kg moisture-proof kraft paper bags with inner PE liner — easy to carry, ideal for construction sites.
Jumbo Bags (FIBC)
500kg, 600kg and 1000kg plastic woven bags, 2 per pallet, with or without bottom discharge spout — built for bulk handling.
Custom Logo Packaging
Your own logo, bag design and marking — professional OEM service to build your brand worldwide.
Contact Us
GET A QUOTECall Us
+86 13109355617Email Address
ewende@microsilica-si.comFAQ about 92% densified silica fume
Ewende's mission is to provide professional services, high quality products and strict after-sales control — and to actively solve customer problems for mutual benefit.
Are you a factory or a middleman?
Ewende New Materials Co., Ltd. is a professional manufacturer and supplier of micro silica powder, with a variety of submerged arc furnace types.
How long will delivery take?
Usually around 15 days after order confirmation or deposit.
What are the payment terms?
TT, L/C and D/P; Paypal is also available.
What is your MOQ?
Usually 10 tonnes to start.
Can you print our brand or logo on the packing?
We offer neutral packing; logo spraying on the outer packaging can be negotiated according to the actual quantity.
Can you offer samples for testing?
Yes. Samples are free in testing quantity; larger amounts are considered by our customer service department.
GET A QUOTE
All-Grade Price List, Within 24 Hours
One form, twelve grades. A sales engineer replies with the full FOB price list + freight to your port — or just the grades you mark.
- ✔Full 12-grade price list as PDF
- ✔Free samples of the grades you shortlist
- ✔Engineer helps you pick if you're between grades