same paragraph. The range between each consecutive flow test for each
type of mixture shall be plotted on a single control chart for range on
which an upper action limit is set at 2 seconds. Samples for flow
shall be taken at the agitator; however, the Contractor is responsible
for delivering the grout to the placement site at the stipulated flow.
If the Contractor's materials or transportation methods cause flow loss
between mixer and the placement, correlation samples shall be taken at
the placement site as required by the Contracting Officer and the flow
at the mixer controlled as directed.
b. Grout Flow Corrective Action - Whenever points on the control chart
for flow reach the upper warning limit, an adjustment shall be
immediately 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 allowed by the maximum W/C specified, based upon
aggregates which are in a saturated surface-dry condition. When a
single flow reaches the upper or lower action limit, no further grout
shall be delivered to the placing site until proper adjustments have
been made. Immediately after each adjustment, another test shall be
made to verify the correctness of the adjustment. Whenever two
consecutive flow tests, made during a period when there was no
adjustment of batch weights, produce a point on the control chart for
range at or above the upper action limit, the grouting operation shall
immediately be halted, and the Contractor shall take appropriate steps
to bring the flow under control. Also, additional flow tests shall be
made as directed. All this shall be at no additional cost to the
Government.
c. Temperature - The temperature of the grout shall be measured when
compressive strength specimens are fabricated. Measurement shall be in
accordance with ASTM C 1064/C 1064M. The temperature shall be reported
along with the compressive strength data.
d. Compressive-Strength Specimens - At least one set of test specimens
shall be made each day on each different preplaced-aggregate concrete
mixture placed during the day. Additional sets of test cylinders shall
be made, as directed by the Contracting Officer, when the mixture
proportions are changed or when low strengths have been detected. A
random grout sampling plan shall be developed by the Contractor and
approved prior to the start of construction. The plan shall assure
that sampling is done in a completely random and unbiased manner. A
set of test specimens for concrete with a 28-day specified strength,
per paragraph DESIGN REQUIREMENTS, shall consist of six cylinders,
three to be tested at 7 days and three at 28 days. A set of test
specimens for concrete with a 90-day strength, per paragraph DESIGN
REQUIREMENTS, shall consist of nine cylinders, three tested at 7 days,
three at 28 days, and three at 90 days. Test specimens shall be molded
and cured in accordance with ASTM C 943 and tested in accordance with
ASTM C 39/C 39M. All compressive-strength tests shall be reported
immediately to the Contracting Officer. 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.
3.6.2.8
Inspection Before Pumping Grout
Foundation or construction joints, forms, and embedded items shall be
inspected for quality by the Contractor in sufficient time prior to each
grout placement to certify to the Contracting Officer that they are ready
SECTION 03372
Page 35
Previous Page
