of at least [_____] cubic meters yards per hour.
3.1.2
Batch Plant
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NOTE: See EM 1110-2-2000, and the concrete
materials design memorandum for selection of
automatic or semiautomatic plant.
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Batch plant shall meet the following requirements.
3.1.2.1
Location
The concrete plant [shall] [may] be located at the site of the work in the
general area indicated on the drawings, [or may be located offsite].
3.1.2.2
Bins and Silos
Separate bins, compartments, or silos shall be provided for each size or
classification of aggregate and for each of the cementitious materials.
The compartments shall be of ample size and so constructed that the various
materials will be maintained separately under all working conditions. All
compartments containing bulk cement, pozzolan, ground granulated
blast-furnace slag, or silica fume shall be separated from each other by a
free-draining air space. All filling ports shall be clearly marked with a
permanent sign stating the contents.
3.1.2.3
Batching Equipment
a. Batchers - Aggregate shall be weighed in separate weigh batchers
with individual scales. Bulk cement and/or other cementitious
materials shall each be weighed on a separate scale in a separate weigh
batcher. Water shall be measured by weight or by volume. If measured
by weight, it shall not be weighed cumulatively with another
ingredient. Ice shall be measured separately by weight. Admixtures
shall be batched separately and shall be batched by weight or by volume
in accordance with the manufacturer's recommendations.
b. Water Batcher - A suitable water-measuring and batching device
shall be provided that will be capable of measuring and batching the
mixing water within the specified tolerances for each batch. The
mechanism for delivering water to the mixers shall be free from leakage
when the valves are closed. The filling and discharge valves for the
water batcher shall be so interlocked that the discharge valve cannot
be opened before the filling valve is fully closed. When a water meter
is used, a suitable strainer shall be provided ahead of the metering
device.
c. Admixture Dispensers - A separate batcher or dispenser shall be
provided for each admixture. Each plant shall be equipped with the
necessary calibration devices that will permit convenient checking of
the accuracy of the dispensed volume of the particular admixture. The
batching or dispensing devices shall be capable of repetitively
controlling the batching of the admixtures to the accuracy specified.
Piping for liquid admixtures shall be free from leaks and properly
valved to prevent backflow or siphoning. The dispensing system shall
include a device or devices that will detect and indicate the presence
or absence of the admixture or provide a convenient means of visually
SECTION 03700
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