NOMINAL MAXIMUM-SIZE
FEATURES
AGGREGATE
Sections 7-1/2 in. or less in width or
slabs 4 in. or less in thickness or any
section with a clear distance between reinforcement
less than 2-1/4 in. ....................................... 3/4 in.
Sections over 7-1/2 in. or slabs at least
4 in. in thickness. However, this size shall
not be used in any section in which the clear
distance between reinforcement is less than
2-1/4 in. .............................................. 1-1/2 in.
[Unreinforced sections over 12 in. in width
and reinforced sections over 18 in. in width
or slabs 10 in. or greater in thickness.
However, this size shall not be used in any section
in which the clear distance between reinforcing
bars is less than 4-1/2 in. ................................ 3 in.]
[Massive sections exceeding 6 ft in width
and slabs 24 in. in thickness, in which
the clear distance between reinforcing bars
is at least 9 in. .......................................... 6 in.]
2.2.5
Air Content
The air content by volume shall be determined by ASTM C 231. When the
nominal maximum size of coarse aggregate is 37.5 mm 1-1/2 inches or larger,
the air content of the sample measured in accordance with ASTM C 231 shall
be 5-1/2 1-1/2 percent. When the nominal maximum-size coarse aggregate
is 19 mm 3/4 inch, the air content shall be 6 1 percent. The specified
air content shall be present in the concrete when the concrete has been
placed in the forms.
2.2.6
Slump
The slump shall be determined in accordance with ASTM C 143/C 143M and
shall be 50 mm 2 inches 25 mm 1 inch for massive features and between 25
and 100 mm 1 and 4 inches for all others except where placement by pump is
approved, in which case the slump shall be 114 mm 4-1/2 38 mm 1-1/2 inches.
In addition, the range of each set of two consecutive tests for each
mixture shall be not more than 50 mm 2 inches. The above specified slump
is that required at the forms.
PART 3
EXECUTION
3.1
EQUIPMENT
3.1.1
Capacity
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NOTE: See the concrete materials design memorandum
or EM 1110-2-2000 for the plant size requirements.
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The batching, mixing, conveying, and placing systems shall have a capacity
SECTION 03700
Page 45
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