to prevent segregation and where specifically authorized. Depositing of
the concrete shall be so regulated that it will be effectively placed and
consolidated in horizontal layers not exceeding 1.5 m 5 feet in thickness
with a minimum of lateral movement. The amount of concrete deposited shall
be such that it can be readily and thoroughly consolidated and shall not
exceed 3 cubic meters 4 cubic yards in one pile. All concrete-placing
equipment and methods shall be subject to approval. Concrete placement
will not be permitted when, in the opinion of the Contracting Officer,
weather conditions prevent proper placement and consolidation.
3.3.2.1
Time Interval Between Mixing and Placing
Concrete mixed in stationary mixers and transported by nonagitating
equipment shall be placed within 30 minutes after it has been mixed, unless
otherwise authorized. When concrete is truck mixed or when a truck mixer
or agitator is used for transporting concrete mixed by stationary mixers,
the concrete shall be delivered to the site of the work, and discharge
shall be completed within 1 hour after introduction of the cement to either
the water or aggregate.
3.3.2.2
Hot-Weather Placing
**************************************************************************
NOTE: See EM 1110-2-2000 for the proper placing
temperature.
**************************************************************************
The temperature of the concrete when deposited in the forms during hot
weather shall not exceed [_____] degrees C F except as further required by
paragraph TRANSPORTING AND PLACING. An approved retarding admixture may be
used in accordance with paragraph MATERIAL SPECIFICATION to facilitate
placing and finishing. Steel forms and reinforcement and conveying and
placing equipment shall be cooled if necessary to assist in maintaining
specified concrete-placing temperature. The temperature of the fresh
concrete shall be measured in accordance with ASTM C 1064/C 1064M.
3.3.2.3
Cold Weather Placing
The temperature of the concrete when deposited in the forms shall not be
less than 5 degrees C 40 degrees F. The ambient temperature of the
placement area and all surfaces to receive concrete shall be above 0
degrees C 32 degrees F. Materials entering the mixer shall be free from
ice, snow, and frozen lumps. The heating of mixing water or aggregates
necessary to keep the concrete temperature above 5 degrees C 40 degrees F
shall be closely regulated so that the concrete temperature does not exceed
15 degrees C 60 degrees F. An accelerator may be used when approved in
advance.
3.3.2.4
[Special Temperature-Controlled Concrete
**************************************************************************
NOTE: See the appropriate concrete materials design
memorandum or thermal study to fill in blanks
**************************************************************************
Special temperature control is applicable to concrete in the following
structures: [_____]; [_____]; [_____]. Regardless of requirements
specified above, the concrete shall have a temperature of not more than
[_____] degrees C F and not less than 5 degrees C 40 degrees F when
SECTION 03700
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