d. Slump Corrective Action - Whenever points on the control chart
approach the upper or lower control limits, an adjustment shall be made
in the batch weights of water and fine aggregate. The adjustments are
to be made so that the total water content does not exceed that amount
specified in the mixture proportions provided based on the free water
available with the aggregates and that amount of water batched. If the
adjustments to the batch weights of water and aggregates do not
satisfactorily produce the required slump, the Contracting Officer may
adjust the mixture proportions if the fine-aggregate moisture content
is stable and within the required limits. When a single slump is
outside the control limits, such adjustment is mandatory. As soon as
practical after each adjustment, another test shall be made to verify
the correctness of the adjustment. Whenever two consecutive individual
slump tests, made during a period when there was no adjustment of batch
weights, produce a point on the control chart for range above the upper
control limits, the slump shall be considered to be out of control, the
concreting operation halted, and the additional testing for aggregate
moisture content required shall be undertaken, and action taken
immediately to correct the problem.
e. Compression Test Cylinders - At least one set of test cylinders
shall be made each shift on each different concrete mixture placed
during the shift. Additional sets of test cylinders shall be made, as
directed, when the mixture proportions are changed or when low
strengths have been detected. A random sampling plan shall be
developed by the Contractor and approved by the Contracting Officer
prior to start of construction. The plan shall assure that sampling is
done in a completely random and unbiased, not just haphazard, manner.
A set of test cylinders for structural concrete containing Type I or
Type II portland cement only shall consist of six cylinders, two to be
tested at 24 hours, two at 7 days, and two at 28 days. A set of test
cylinders for all other concrete shall consist of six cylinders, two to
be tested at 24 hours, one at 7 days, one at 28 days, and two at 90
days. In addition, for all concrete except that containing Type I or
Type II portland cement only, every 2 months four additional cylinders
shall be made and two tested at 6 months of age and two tested at 12
months of age. The 24-hour test cylinders shall be molded, cured, and
tested in accordance with ASTM C 684, Method A. All other test
specimens shall be molded and cured in accordance with ASTM C 31/C 31M
and tested in accordance with ASTM C 39/C 39M. All compressive
strength tests shall be reported immediately. Quality control charts
shall be kept for individual strength tests, moving average for
strength and moving average for range for each mixture. The charts
shall be similar to those found in ACI 214R.
3.8.2.7
Inspection Before Placing
Foundation or construction joints, forms, and embedded items shall be
inspected by the Contractor in sufficient time prior to each concrete
placement in order to certify that they are ready to receive concrete.
The
results of each inspection shall be reported in writing.
3.8.2.8
Concrete Placement
a. Placing Inspection - The placing foreman shall supervise all
placing operations, shall determine that the correct quality of
concrete or grout is placed in each location as directed, and shall be
responsible for measuring and recording concrete temperatures and
SECTION 03700
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