Concrete Piles."
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If required, ASTM C 494, [Type A] [Type B] and ASTM C 618, Type [N] [F]
[C]. Do not use admixtures containing chlorides.
2.1.5
Mineral Admixtures
2.1.5.1
Fly Ash and Pozzolan
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NOTE: Fly ash, pozzolan, and slag cement may
produce uneven discoloration of the concrete during
the early stages of construction, depending upon the
type of curing provided. Fly ash or pozzolan
meeting the specified test results, which are more
stringent than ASTM C 618, should provide acceptable
end results. Type C fly ash can be used as a
replacement for up to 40 percent of the cement.
Types F and C fly ash increase durability of
concrete. Type F fly ash and slag are replacements
for some sand and aggregates also adding to
durability.
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ASTM C 618, Type N, F, or C, except that the maximum allowable loss on
ignition shall be 6 percent for Types N and F. Add with cement. Fly ash
content shall not exceed 25 percent by weight of the total cementitious
material.
2.1.5.2
Silica Fume
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NOTE: Use silica fume concrete for marine
structures where low permeability and enhanced
durability are necessary. The silica fume and HRWR
additive should be from the same manufacturer.
Since this is fairly new technology, the Contractor
and batch plant may need help from the manufacturer.
Select weight percentage based on performance
required.
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NOTE: Use for high durability and low permeability.
The initial cost of the concrete will increase,
and supervision at the batch plant, finishing, and
curing is necessary. A HRWR must be used with
silica fume, the slump can be increased 50 to 125 mm
2 to 5 inches without reducing strength.
Finishing
may be more difficult. Proper curing is essential
because there is a tendency for plastic shrinkage
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ASTM C 1240, provide silica fume that is a by-product of silicon or
ferrosilicon production. Provide [5] [7] [10] percent by weight of the
total cementitious material.
SECTION 02395
Page 11
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