This standard specifies the requirements for silica fume, a highly pozzolanic material, for use as a mineral admixture in cement, mortar, and concrete. It covers physical, chemical, and performance criteria, including silicon dioxide content, fineness, and pozzolanic activity. The standard ensures the quality and consistency of silica fume used for producing high-strength and high-durability concrete.
Specifies requirements for silica fume for use as an admixture in hydraulic cement concrete and mortar.
Quick Reference Values
Minimum Silicon Dioxide (SiO2) content85.0 % by mass
Minimum Specific Surface Area15 m²/g
Maximum Moisture Content3.0 % by mass
Maximum Loss on Ignition6.0 % by mass
Minimum Pozzolanic Activity Index at 28 days100 %
Maximum Oversize material retained on 45 micron sieve10.0 % by mass
Practical Notes
Silica fume is an extremely fine powder, requiring careful handling with personal protective equipment (PPE) to prevent inhalation and proper dispersion in the concrete mix to avoid agglomeration.
Due to its high surface area, concrete with silica fume has a higher water demand and reduced workability; use of a high-range water reducer (superplasticizer) is almost always necessary.
It is typically used in proportions of 5% to 10% by weight of cementitious material for significant improvement in strength and durability.