Journal Published Online: 01 January 1984
Volume 6, Issue 2

The Uniformity and Influence of Silica Fume from a U.S. Source on the Properties of Portland Cement Concrete



Silica fume is formed during the manufacture of ferrosilicon in electric submerged-arc furnaces. The use of silica fume has been evaluated in portland cement concrete. Thirty samples of silica fume, each collected on consecutive days from SKW Alloys, Inc. in Calvert City, KY, were analyzed for routine quality control tests of a pozzolan. Six of these samples, representing the variations of the routine tests, were tested for complete ASTM Specification for Fly Ash and Raw or Calcined Natural Pozzolan for Use as a Mineral Admixture in Portland Cement Concrete (C 618) conformance. Laboratory mixtures of air-entrained and nonair-entrained concrete, containing a representative sample of silica fume, were cast for compressive strength (1 to 120 days), drying shrinkage, and time of set. Although a classification for silica fume is not currently contained in ASTM C 618, all of the samples tested were found to conform when compared to the requirements of this standard, with the exception that the water requirement was excessive.

Concrete mixtures containing only 24 kg/m3 (40 lb/yd3) of silica fume showed slightly high shrinkage at 64 weeks of drying with the lower cement content mixtures relative to control mixtures. The silica fume mixtures showed 120 to 180% higher compressive strength at 120 days in lean mixtures, 110 to 120% higher compressive strength in richer mixtures. This amount of silica fume was found to have no effect on initial set of concrete and had only a slightly longer final set.

Author Information

Pistilli, MF
American Admixtures and Chemicals Corp., Chicago, IL
Wintersteen, R
Environmental Control, SKW Alloys Inc., Niagara Falls, NY
Cechner, R
American Admixtures and Chemicals Corp., Chicago, IL
Pages: 5
Price: $25.00
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Stock #: CCA10364J
ISSN: 0149-6123
DOI: 10.1520/CCA10364J