This graph shows the results of abrasion-erosion testing done by the Corps
of Engineers according to their own underwater test method*. The upper line
labeled "Kinzua cores" shows the results of testing large-diameter cores
taken from the stilling basin concrete shown in the previous slide. The G1
aggregate is the locally available aggregate in a concrete with conventional
compressive strength. The Chert aggregate line is a reference concrete made
with a very hard aggregate. The silica fume line represents the G1
aggregate in concrete containing silica fume with a compressive strength of
about 12,000 psi (83 MPa). Based upon the results of such testing, the
Corps of Engineers specified silica- fume concrete with a minimum 28-day
compressive strength of 12,500 psi (86 MPa) for the second repair.
*CRD-C 63-80, Test Method for Abrasion-Erosion Resistance of Concrete
(Underwater Method).
The Silica Fume Association
38860 Sierra Lane, Lovettsville, VA 20180
Tel: 540.257.4224 Fax: 540.822.9456
