least 72 hours after compound application. Maintain continuity of the
coating for the entire curing period and immediately repair any damage.
3.9.3
Liquid Chemical Sealer-Hardener
Apply sealer-hardener to interior floors not receiving floor covering and
floors located under access flooring. Apply the sealer-hardener in
accordance with manufacturer's recommendations. Seal or cover joints and
openings in which joint sealant is to be applied as required by the joint
sealant manufacturer. The sealer-hardener shall not be applied until the
concrete has been moist cured and has aged for a minimum of 30 days. Apply
a minimum of two coats of sealer-hardener.
3.9.4
Curing Periods
ACI 301 except 10 days for retaining walls, pavement or chimneys, 21 days
for concrete that will be in full-time or intermittent contact with
seawater, salt spray, alkali soil or waters. Begin curing immediately
after placement. Protect concrete from premature drying, excessively hot
temperatures, and mechanical injury; and maintain minimal moisture loss at
a relatively constant temperature for the period necessary for hydration of
the cement and hardening of the concrete. The materials and methods of
curing shall be subject to approval by the Contracting Officer.
3.9.5
Requirements for Type III, High-Early-Strength Portland Cement
The curing periods shall be not less than one-fourth of those specified for
portland cement, but in no case less than 72 hours.
3.10
FIELD QUALITY CONTROL
3.10.1
Sampling
ASTM C 172. Collect samples of fresh concrete to perform tests specified.
ASTM C 31/C 31M for making test specimens.
3.10.2
Testing
3.10.2.1
Slump Tests
ASTM C 143/C 143M. Take concrete samples during concrete placement. The
maximum slump may be increased as specified with the addition of an
approved admixture provided that the water-cement ratio is not exceeded.
Perform tests at commencement of concrete placement, when test cylinders
are made, and for each batch (minimum) or every 16 cubic meters (20 cubic
yards) 20 cubic yards (maximum) of concrete.
3.10.2.2
Temperature Tests
Test the concrete delivered and the concrete in the forms. Perform tests
in hot or cold weather conditions (below 10 degrees C and above 27 degrees
C (below 50 degrees F and above 80 degrees F)below 50 degrees F and above
80 degrees F) for each batch (minimum) or every 16 cubic meters (20 cubic
yards) 20 cubic yards (maximum) of concrete, until the specified
temperature is obtained, and whenever test cylinders and slump tests are
made.
SECTION 03300N
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