small batches into larger batch hoppers, trucks, or truck beds.
f. Trial operation - Not less than 7 days prior to commencement of
concrete placing, a test of the plant shall be made in the presence of
a representative of the Contracting Officer to check operational
adequacy. The number of cubic meters yards required to be produced in
trial runs shall be as directed, but will not exceed 40 cubic meters 50
cubic yards and shall be proportioned as directed by the Contracting
Officer. All concrete produced in these tests shall be wasted or used
for purposes other than inclusion in structures covered by this
specification. All deficiencies found in plant operation shall be
corrected to the satisfaction of the Contracting Officer prior to the
start of concrete placing operations. Mixer uniformity tests by the
Government will be performed near the end of this trial period. No
separate payment will be made to the Contractor for labor or materials
required by provisions of this paragraph. The Contractor shall notify
the Contracting Officer of the trial operation not less than 7 days
prior to the start of the trial operation.
g. Protection - The weighing, indicating, recording, and control
equipment shall be protected against exposure to dust, moisture, and
vibration so that there is no interference with proper operation of the
equipment.
3.1.2.5
Laboratory Areas
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NOTE: The specification writer should use the
alternate sentence and fill in the correct section
number unless a laboratory building is to be
government furnished.
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A room shall be provided adjacent to the plant to house the moisture and
grading testing equipment for aggregate and to provide working space for
the Government representative. Another room shall be provided for testing
fresh concrete and for fabricating and initial curing (approximately 72
hours) of concrete test specimens in accordance with ASTM C 31/C 31M. The
size, arrangement, and location of these rooms will be subject to approval
by the Contracting Officer. The Contractor shall provide electricity,
air-conditioning, heat, and water as required for use in these laboratory
areas. [[Section [_____]] [_____] of these specifications presents
requirements for a separate building equipped for a testing laboratory.]
3.1.3
Mixers
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NOTE: See the concrete materials DM for information
on mixer selection and concrete mixers. Truck
mixers shall not be allowed for mixing or
transporting RCC or conventional concrete with less
than 50 mm (2 inch) slump or greater than 37.5 mm
(1-1/2 inch) nominal maximum size aggregate (NMSA).
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Mixers shall be stationary mixers or pugmill
mixers. [Truck mixers may be
used for conventional concrete]. Mixers may
be batch or continuous mixing.
Each mixer shall combine the materials into
a uniform mixture and
discharge this mixture without segregation.
Mixers shall not be charged in
SECTION 03701
Page 37
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