94% Undensified Silica Fume



94% Undensified Silica Fume



94% Undensified Silica Fume is a micro-silica fume with 94% SiO2 content, and the Bulk density is 240-320kg/m³.

Silica fume 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.


In the application of high-strength, high abrasion resistance, underwater casting of anti-scattering concrete, etc., the amount of silica fume admixture should not be too low usually accounting for 5%-10% of the cementitious material.

Use Ewende silica fume powder preparation of high-strength, early-strength concrete should be used with high-efficiency water reducing agent, with high-strength concrete should be selected with low air-entraining high-efficiency water reducing agent, depending on the situation can add defoamer.

In ordinary strength, impermeable, highly durable or self-compacting concrete applications, it is appropriate to use a multi-component cementitious material with low silica fume admixture, usually accounting for 2%-5% of the cementitious material.

The addition of silica fume powder needs to extend the mixing time, can not be mixed in wet concrete after mixing, it is recommended to extend the mixing time of 30 seconds than ordinary concrete to ensure uniform mixing.

Plastic shrinkage crack sensitive, better maintenance method is: spray concrete has not yet set, spraying curing agent maintenance; concrete hardening, the use of maintenance film, covered with wet sacks or plastic film.


StateAmorphous -Sub-micron powder
ColorGray to medium gray powder
Specific Gravity2.10 to 2.40
Bulk Density -Densified42 to 48 lb/'(500 to 650 kg/m³)
Bulk Density -Undensified “as produced”12 to 20 lb/(300 to 450 kg/m³)
Chemical RequirementsASTMTypical
Silicon Dioxide (SiO₂)%90.0 % Minimum0.9347
Moisture Content %3.0% Maximum0.0027
Loss on Ignition (LOI) %6.0% Maximum0.0382
Physical RequirementsASTMTypical
Oversize percent retained on 45-um (325 sieve)10.0 % Maximum0.0254
Accelerated Porzolaric Strength Activity Index
with Portland cement(7 day)
105.0% Minimum1.2607
Specific Surface15 ㎡/g Minimum22.28㎡/g
National Standards for Silica Fume for Concrete
National Standards and OrganizationsEuropeNorwayFranceAustraliaUnited StatesCanadaJapanChina
Standard Number132633045P18-50235861240A23.5A62071873627690
SiO2 %   ≥858585858585858585
SO3  %   <2 2.53 13  
CI- %   <0.3Report0.2Report
CaO  %   <12    1  
MgO  %   <      5  
Si %  <0.4     0.4  
Na2O+K2O     %  <  4     1.5
C    %   <  4      
Water Content   %   <   23 333
Burn Vector   %   <45 666564
Specific Surface Area ㎡/g15-35≥1220-35   ≥15≥15≥15
45μm Sieve Residue  %   <    1010 5 
Loose capacity   kg/m³   ReportReport    
Specific Gravity g/㎝³  2.1-2.3   Report  
Water Demand Ratio     %   ≤       125125
Volcanic Ash Activity Index%(3d)  ≥         
%(7d)  ≥   Report105858595105
%(28d) ≥10095    100115 
Water to Glue Ratio0.50.5  0.484
ConservationStandardStandard  AcceleratedAcceleratedStandardStandardAccelerated



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