b. Corrective Action for Fine Aggregate Grading - When the amount
passing on any sieve is outside the specification limits, the fine
aggregate shall be immediately resampled and retested. If there is
another failure on any sieve, the fact shall immediately be reported to
the Contracting Officer.
c. Moisture Content Testing - When in the opinion of the Contracting
Officer the electric moisture meter is not operating satisfactorily,
there shall be at least four tests for moisture content in accordance
with ASTM C 566 during each 8-hour period of mixing plant operation.
The times for the tests shall be selected randomly within the 8-hour
period. An additional test shall be made whenever the slump is shown
to be out of control or excessive variation in workability is reported
by the placing foreman. When the electric moisture meter is operating
satisfactorily, at least two direct measurements of moisture content
shall be made per week to check the calibration of the meter. The
results of tests for moisture content shall be used to adjust the added
water in the control of the batch plant.
d. Moisture Content Corrective Action - Whenever the moisture content
of the fine aggregate changes by 0.5 percent or more, the scale
settings for the fine-aggregate batcher and water batcher shall be
adjusted (directly or by means of a moisture compensation device) if
necessary to maintain the specified slump.
3.7.2.2
Coarse Aggregate
a. Grading - At least once during each shift in which the concrete
plant is operating, there shall be a sieve analysis in accordance with
ASTM C 136 for each size of coarse aggregate. The location at which
samples are taken may be selected by the Contractor as the most
advantageous for production control. However, the Contractor shall be
responsible for delivering the aggregate to the mixer within
specification limits. A test record of samples of aggregate taken at
the same locations shall show the results of the current test as well
as the average results of the five most recent tests including the
current test. The Contractor may adopt limits for control which are
coarser than the specification limits for samples taken at locations
other than as delivered to the mixer to allow for degradation during
handling.
b. Corrective Action for Grading - When the amount passing any sieve
is outside the specification limits, the coarse aggregate shall be
immediately resampled and retested. If the second sample fails on any
sieve, that fact shall be reported to the Contracting Officer. Where
two consecutive averages of five tests are outside specification
limits, the operation shall be considered out of control and shall be
reported to the Contracting Officer. Concreting shall be stopped and
immediate steps shall be taken to correct the grading.
c. Coarse Aggregate Moisture Content - A test for moisture content of
each size group of coarse aggregate shall be made at least twice per
week. When two consecutive readings for smallest size coarse aggregate
differ by more than 1.0 percent, frequency of testing shall be
increased to that specified above for fine aggregate, until the
difference falls below 1.0 percent.
d. Coarse Aggregate Moisture Corrective Action - Whenever the moisture
content of any size of coarse aggregate changes by 0.5 percent or more,
SECTION 03301A
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