Silica Fume is a high performance, densified silica fume powdered product, derived as a by-product from the production of Ferro Silicon using the arc furnace method. Used in pre-mixed concrete for enhancing mechanical properties of concretes with special performance requirements, including increased strength, reduced permeability, improved abrasion resistance and increased corrosion resistance.

Silica fume consists of very fine particles. Because of its extreme fineness and high silica content, silica fume is a highly effective pozzolanic material. Being a highly reactive pozzolan, silica fume chemically reacts with the calcium hydroxide present in the cement paste, creating a stronger calcium silica hydrate 'making it sticky'. The result is improved paste to aggregate bond (excellent for shotcrete) and higher concrete strengths. Silica Fume is typically grey in colour and is categorised as supplementary cementitious material (SCM). Silica Fume is compliant to AS/NZ 3582.3:2002 and is described as a Densified Amorphous Fumed Silica.