cubic meters yards per hour.
3.1.2
Batching Equipment
All materials shall be mechanically batched by mass except the water and
admixture which may be batched by volume.
3.1.2.1
Scales
The equipment used for determining mass shall conform to the applicable
requirements of NIST HB 44, except that the accuracy shall be plus or minus
0.2 percent of scale capacity. The Contractor shall provide standard test
reference masses and any other auxiliary equipment required for checking
the operating performance of each scale or other measuring devices. The
tests shall be made at the frequency required in paragraph TESTING AND
QUALITY VERIFICATION FOR CONTRACTOR QUALITY CONTROL in the presence of a
Government representative.
3.1.2.2
Batching Tolerances
a.
Tolerances on Mass
MATERIAL
PERCENT OF REQUIRED MASS
Cementitious materials
0 to plus 2
Aggregate
plus or minus 2
Water
plus or minus 1
Chemical admixture
0 to plus 6
b.
Volumetric Tolerances
For volumetric batching equipment, the following tolerances shall apply
to the required volume of material being batched:
Water: plus or minus 1 percent.
Chemical admixtures: Zero to plus 6 percent.
3.1.2.3
Grout Mixer
The grout mixer shall be a machine especially designed for the mixing of
grout and shall be capable of mixing grout mechanically to a uniform
consistency. The mixer shall be maintained in satisfactory operating
condition and kept free of hardened grout. Should any grout mixer at any
time produce unsatisfactory results, its use shall be promptly discontinued
until the condition is corrected. The grout mixer shall be provided with
an acceptable device to lock the discharge mechanism until the required
mixing time has elapsed. Use of revolving-drum concrete mixers will not be
permitted.
3.1.2.4
Agitator Tank
The agitator tank shall have at least the same capacity as the mixer and
shall be equipped to agitate the grout effectively and continuously. All
grout entering the tank shall be passed through a wire sieve. The sieve
size shall not be less than 4.75 mm (No. 4) and not greater than 9.5 mm
(3/8 inch).
SECTION 03372
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