Silica fume has also been used to provide increased resistance for concrete
exposed to a variety of aggressive chemicals. In these applications, the
amount of silica fume is typically much greater than that used for other
durability applications -- 15 percent by mass of cement or higher.
Silica fume does not make concrete resistant to chemical attack, but it may
prolong the life of the concrete. The primary improvement in performance
results form the reduced permeability of the silica-fume concrete. It
simply takes the aggressive chemicals much longer to penetrate.
Additionally. Depending upon the amount of silica fume in the concrete, the
amount of free calcium hydroxide, which is leached by or reacts with
attacking chemicals, can be significantly reduced. See the paper by Durning
and Hicks for additional information.
In applications that can tolerate little down time for repairs to concrete,
extending the time between repairs can mean significant repair cost savings
and reduced loss of production time to the owner.
Durning, T. A., and Hicks, M. C., "Using Microsilica to Increase Concrete's
Resistance to Aggressive Chemicals," Concrete International, Vol. 13, No. 3,
March, 1991, pp. 42-48.
The Silica Fume Association
38860 Sierra Lane, Lovettsville, VA 20180
Tel: 540.257.4224 Fax: 540.822.9456
