MATERIAL
PERCENT
Water ........................................ 1
Aggregate smaller than
37.5 mm 1-1/2 in size .............................
2
Aggregate larger than
37.5 mm 1-1/2 in size ..............................
3
Chemical admixtures ..........................
3
g.
Interlocks - Batchers and mixers shall be interlocked so that:
(1) The charging device of each batcher cannot be actuated until
all scales have returned to zero balance within 0.2 percent of
the scale capacity and each volumetric device has reset to start
or has signaled empty.
(2) The charging device of each batcher cannot be actuated if the
discharge device is open.
(3) The discharge device of each batcher cannot be actuated if
the charging device is open.
(4) The discharge device of each batcher cannot be actuated until
the indicated material is within the allowable tolerances.
(5)
One admixture is batched automatically with the water.
(6) Each additional admixture is batched automatically with a
separate portion of the water or with the fine aggregate.
(7) The mixers cannot be discharged until the required mixing
time has elapsed.
h. Recorder - An accurate recorder or recorders shall be provided and
shall conform to the following detailed requirements:
(1) The recorder shall produce a graphical or digital record on a
single visible chart or tape of the weight or volume of each
material in the batchers at the conclusion of the batching cycle.
The record shall be produced prior to delivery of the materials to
the mixer. After the batchers have been discharged, the recorder
shall show the return to empty condition.
(2) A graphical recording or digital printout unit shall be
completely housed in a single cabinet that shall be capable of
being locked.
(3) The chart or tape shall be so marked that each batch may be
permanently identified and so that variations in batch weights of
each type of batch can be readily observed. The chart or tape
shall be easily interpreted in increments not exceeding 0.5
percent of each batch weight.
(4) The chart or tape shall show time of day at intervals of not
more than 15 minutes.
SECTION 03700
Page 48
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