depth by wood tampers, spading, and settling with a heavy leveling
straightedge. Operate internal vibrators with vibratory element submerged
in the concrete, with a minimum frequency of not less than 6000 impulses
per minute when submerged. Do not use vibrators to transport the concrete
in the forms. Insert and withdraw vibrators approximately 500 mm (18
inches) 18 inches apart. Penetrate the previously placed lift with the
vibrator when more than one lift is required. Place concrete in 500 mm
(18 inches) 18 inch maximum vertical lifts. External vibrators shall be
used on the exterior surface of the forms when internal vibrators do not
[3.6.3
Application of Epoxy Bonding Compound
Apply a thin coat of compound to dry, clean surfaces. Scrub compound into
the surface with a stiff-bristle brush. Place concrete while compound is
stringy. Do not permit compound to harden prior to concrete placement.
Follow manufacturer's instructions regarding safety and health precautions
when working with epoxy resins.
][3.6.4
Pumping
**************************************************************************
NOTE: Pumping, especially lightweight concrete,
requires careful attention to mix designs and
pumping procedures. Allow pumping when other means
of placement will be impractical or expensive.
**************************************************************************
ACI 304R and ACI 304.2R. Pumping shall not result in separation or loss of
materials nor cause interruptions sufficient to permit loss of plasticity
between successive increments. Loss of slump in pumping equipment shall
not exceed 50 mm (2 inches) 2 inches. Concrete shall not be conveyed
through pipe made of aluminum or aluminum alloy. Rapid changes in pipe
sizes shall be avoided. Maximum size of course aggregate shall be limited
to 33 percent of the diameter of the pipe. Maximum size of well rounded
aggregate shall be limited to 40 percent of the pipe diameter. Samples for
testing shall be taken at both the point of delivery to the pump and at the
discharge end.
][3.6.4.1
Pumping Lightweight Concrete
**************************************************************************
NOTE: Specify minimum of 330 kg per cubic meter
(564 pounds per cubic yard) 564 pounds per cubic yard
unless structural considerations require higher
cement content. Require field trial run only when
justified by job complexities or size.
**************************************************************************
ACI 213R. Aggregates shall be presoaked or presaturated. Cement content
shall be minimum of [330 kg per cubic meter (564 pounds per cubic yard)]
[564 pounds per cubic yard] [_____] and shall be sufficient to accommodate a
100 to 150 mm (4 to 6 inch) 4 to 6 inch slump. [Field trial run shall be
made in accordance with ACI 213R.]
][3.6.5
ACI 306.1. Do not allow concrete temperature to decrease below 10 degrees
C (50 degrees F) 50 degrees FObtain approval prior to placing concrete when
SECTION 03300N
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