3.3.2
Transporting and Placing Coarse Aggregate
Coarse aggregate shall be transported to the forms and placed in
substantially horizontal layers by means which will prevent objectionable
segregation and breakage. Foreign material and excessive accumulation of
fine material on the lift surface shall be removed before placing the next
lift. Placing of coarse aggregate under water shall be continuous in each
stage or lift until placement in that stage or lift is completed. When the
coarse aggregate is to be placed in the dry, there shall be no vertical
drop greater than 1.5 m 5 feet except where suitable equipment is provided
to prevent breakage and segregation and where specifically authorized.
Vehicle traffic on top of preplaced-coarse aggregate shall not be permitted.
3.3.3
Cold-Weather Placing of Preplaced-Aggregate Concrete
When the cold-weather placing of preplaced-aggregate concrete is likely to
be subjected to freezing temperatures before the expiration of the curing
period, it shall be placed in accordance with the approved procedure
previously submitted in accordance with paragraph SUBMITTALS. The ambient
temperature of the space adjacent to the preplaced-aggregate concrete
placement and surfaces to receive preplaced-aggregate concrete shall be
above 0 degrees C 32 degrees F. The placing temperature of the preplaced
aggregate concrete having a minimum dimension less than 300 mm 12 inches
shall be between 13 and 24 degrees C 55 and 75 degrees F when measured in
accordance with ASTM C 1064/C 1064M. The placing temperature of the
preplaced-aggregate concrete having a minimum dimension greater than 300 mm
12 inches shall be between 10 and 21 degrees C 50 and 70 degrees F.
Heating of the mixing water or aggregates will be required to regulate the
concrete-placing temperatures. Materials entering the grout mixer shall be
free from ice, snow, or frozen lumps. Salt, chemicals, or other materials
shall not be mixed with the grout to prevent freezing. The forms shall be
free of frost, and the aggregate, when deposited in the form, shall be free
of ice, snow, and frozen lumps.
3.3.4
Hot-Weather Placing of Preplaced-Aggregate Concrete
**************************************************************************
NOTE: See the appropriate DM for the proper placing
temperature.
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Hot-weather placing of preplaced-aggregate concrete shall be properly
placed and finished with the approved procedures previously submitted in
accordance with paragraph SUBMITTALS. The preplaced-aggregate concrete
temperature shall not exceed [_____] degrees C F when measured in
accordance with ASTM C 1064/C 1064M. Cooling of the mixing water may be
required to obtain an adequate placing temperature. A retarder meeting the
requirements of paragraph WATER-REDUCING OR RETARDING ADMIXTURES may be
used to facilitate placing and finishing. Steel forms and reinforcement
shall be cooled prior to concrete placement when steel temperatures are
greater than 49 degrees C 120 degrees F.
3.3.5
Grout Mixing and Pumping
3.3.5.1
Charging Sequence
The order of placing material in the mixer shall be as follows:
a.
Water, or premixed water and fluidifier, if the fluidifier is in a
SECTION 03372
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