Elkem Microsilica® Grade 920 ASTM

Elkem Microsilica® Grade 920 is a dry silica fume powder. In use, Elkem Microsilica® Grade 920 improves the performance of concrete and mortar formulations. It acts physically to optimise particle packing of the concrete or mortar mixture and chemically as a highly reactive pozzolan. Elkem Microsilica® Grade 920 is available in two forms: Undensified (920 U), bulk density typically 200 – 350 kg/m3; and Densified (920 D), bulk density typically 500 – 700 kg/m3


Suitable for all concrete and mortar applications where the benefits of silica fume are required:

  • Higher compressive strength
  • Increased durability – Longer service life for structures
  • Enhanced rheology – Control of mixture segregation & bleed 

Batch Elkem Microsilica® Grade 920 into the concrete mixer and mix thoroughly with the other mixture ingredients, adopting a procedure that ensures full dispersion of the product.  Dosage varies depending on application.  Contact Elkem for information and advice.  


Available in a range of packaging options, including:

  • 25 kg paper bags
  • Big bags in various designs & sizes
  • Bulk road tanker

Please contact our representative for more details

Storage requirements

Elkem Microsilica® Grade 920 powder should be stored in dry conditions and not exposed to moisture.  

Quality Assurance & Quality control

Elkem Silicon Materials’ Management System for development, processing and supply of Elkem Microsilica® is certified to ISO 9001.  The chemical composition and physical properties of Elkem Microsilica® Grade 920 are regularly tested according to requirements set forth in ASTM C 1240-14

Chemical and physical properties

Elkem Microsilica® Grade 920 conforms to ASTM C1240-14, Standard Specification for Silica Fume Used in Cementitious Mixtures (American Society for Testing and Materials).

PropertySpecified value (ASTM C1240-14)
SiO2 Minimum  85 %
H2O Maximum  3 %
Loss on Ignition Maximum  6 %
Specific Surface Area Minimum  15 m2/g
Pozzolanic Activity Index, 7 days Minimum  105 % of control
Retained on 45 micron sieve Maximum 10%