Silica Fume
Description
Silica fume primarily consists of amorphous (non-crystalline) silicon dioxide. The average particle diameter is 0.08 um; specific surface area is about 4500 m2 /kg; and bulk density is 200 – 250kg/m3. Silica fume has extremely high surface activity with unformed spheroidal silica dioxide particle, the particle size is 1% of cement particle size. It will fill fully into the gaps among cement particles and create gel when reacts with hydrate compound.
Usage
Silica fume may be applied with general concrete to enhance mechanical properties:.
1. Improving concrete durability.
2. Enhancing concrete compressive strength and pumpability.
3. Making high anti-crack, waterproofing concrete which been used in the subway, tunnel and basement of high-rise structures.
4. Used in maritime works and chemical industry. Owing to its compactability, it can effectively prevent sulphate and chloride ion from permeating and eroding. It avoids steel corrosion in reinforced concrete, which results in longer life-span of concrete. .
5. Used in the under water construction such as pier, huge dam and drilling platform.
6. Used in concrete surface for high way and large-scale bridge.
7. Used in the production of refractory and porcelain.
Chemical Composition
Items |
SiO2 |
ZrO2 |
Fe2O3 |
Al2O3 |
Na2O |
K2O |
TiO2 |
Content (%) |
75 ~ 95 |
6 ~ 10 |
≤0.4 |
≤0.5 |
≤0.05 |
≤0.02 |
≤0.05 |
Following are three types of silica fume according to different silica dioxide content:
Grades |
Characteristics |
Super-fined silica fume |
SiO2 ≥90%, white powder form, applied in ornamental concrete. |
Grade Ⅰsilica fume |
SiO2 ≥88%, grey powder form, applied in high-strength non-shrinkage grouting materials. |
Grade Ⅱ silica fume |
SiO2 ≥85%, dark grey powder form, applied in high-strength commercial concrete. |
Package, Storage & Handling
1. Packed in woven fabric bag with plastic liner. Net weight:15kg /-0.13kg
2. It should be stored in a dedicated warehouse that is well-ventilated and dry. It remains effective for two years. At the expiration, re-use is allowed if the testing results fall within the established range. In case of humidity, re-use is allowed after drying and crushing.