Silica fume is
a byproduct of producing silicon metal or ferrosilicon alloys. One of
the most beneficial uses for silica fume is in concrete. Because of its
chemical and physical properties, it is a very reactive pozzolan.
Concrete containing silica fume can have very high strength and can be
very durable. Silica fume is available from suppliers of concrete
admixtures and, when specified, is simply added during concrete
production. Placing, finishing, and curing silica-fume concrete require
special attention on the part of the concrete contractor.
fume consists primarily of amorphous (non-crystalline) silicon dioxide
(SiO2). The individual particles are extremely small, approximately
1/100th the size of an average cement particle. Because of its fine
particles, large surface area, and the high SiO2 content, silica fume is
a very reactive pozzolan when used in concrete.