[d. Nonprequalified Pozzolan Sources - Pozzolan, if not from a
prequalified source, will be sampled at the source and stored in sealed
bins pending completion of certain tests. Pozzolan will also be
sampled at the site when determined necessary. All sampling and
testing will be by and at the expense of the Government. Release for
shipment and approval for use will be based on compliance with 7-day
lime-pozzolan strength requirements and other physical and chemical and
uniformity requirements for which tests can be completed by the time
the 7-day lime-pozzolan strength test is completed. Release for
shipment and approval for use on the above basis will be contingent on
continuing compliance with the other requirements of the
specifications. If a bin fails, the contents may be resampled and
tested at the Contractor's expense. In this event the pozzolan may be
sampled as it is loaded into cars, trucks, or barges provided they are
kept at the source until released for shipment. Unsealing and
resealing of bins and sealing of shipping conveyances will be done by
or under the supervision of the Government. Shipping conveyances will
not be accepted at the site of the work unless received with all seals
intact. If pozzolan is damaged in shipment, handling, or storage, it
shall be promptly removed from the site of the work. Pozzolan that has
not been used within 6 months after testing shall be retested at the
expense of the Contractor when directed by the Contracting Officer and
shall be rejected if the test results are not satisfactory. If tested
pozzolan is rehandled at transfer points, the extra cost of inspection
shall be at the Contractor's expense. The cost of testing excess
pozzolan shall be at the Contractor's expense at a rate of [_____]
cents per ton (metric) (2000 lb). The amount will be deducted from
payment to the Contractor.]
1.4.2.3
Concrete Strength
Compressive strength test specimens will be made by the Government and
cured in accordance with ASTM C 31/C 31M and tested in accordance with ASTM
C 39/C 39M. The strength of the concrete will be considered satisfactory
so long as the average of all sets of three consecutive test results equals
or exceeds the specified compressive strength f'c and no individual test
result falls below the specified strength f'c by more than 3.5 MPa 500 psi.
A "test" is defined as the average of two companion cylinders, or if only
one cylinder is tested, the results of the single cylinder test.
Additional analysis or testing, including nondestructive testing, taking
cores and/or load tests may be required at the Contractor's expense when
the strength of the concrete in the structure is considered potentially
deficient.
a. Investigation of Low-Strength Test Results - When any strength test
of standard-cured test cylinders falls below the specified strength
requirement by more than 3.5 MPa 500 psi or if tests of field-cured
cylinders indicate deficiencies in protection and curing, steps shall
be taken to assure that the load-carrying capacity of the structure is
not jeopardized. Nondestructive testing in accordance with ASTM C 597,
ASTM C 803/C 803M, or ASTM C 805 may be permitted by the Contracting
Officer to estimate the relative strengths at various locations in the
structure as an aid in evaluating concrete strength in place or for
selecting areas to be cored. Such tests shall not be used as a basis
for acceptance or rejection.
b. Testing of Cores - When the strength of concrete in place is
considered potentially deficient, cores shall be obtained and tested in
accordance with ASTM C 42/C 42M. At least three representative cores
SECTION 03301A
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