obtain or if structural analysis does not confirm the safety of
the structure, load tests may be directed by the Contracting
Officer in accordance with the requirements of ACI 318/318R.
Concrete work evaluated by structural analysis or by results of a
load test as being understrength shall be corrected in a manner
satisfactory to the Contracting Officer. All investigations,
testing, load tests, and correction of deficiencies shall be
performed by and at the expense of the Contractor and must be
approved by the Contracting Officer, except that if all concrete
is found to be in compliance with the drawings and specifications,
the cost of investigations, testing, and load tests will be at the
expense of the Government.
d.
Evaluation of Concrete Flexural Strength. Flexural strength
specimens (beams) shall be fabricated by the Contractor and
laboratory cured in accordance with ASTM C 31/C 31M and tested in
accordance with ASTM C 78. 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
flexural strength and no individual test result falls below the
specified flexural strength by more than 350 kPa 50 psi. A "test"
is defined as the average of two companion beams. Additional
analysis or testing, including taking cores and/or load tests may
be required at the Contractor's expense when the strength of the
concrete in the slab is considered potentially deficient.
1.8.2.2
Water-Cement Ratio
**************************************************************************
NOTE: Where durability or other factors are a major
consideration, retain this paragraph limiting w/c;
coordinate this subparagraph with paragraph MIXTURE
PROPORTIONS and its subparagraphs before deleting
any of the contents, otherwise delete. When
cementitious materials other than portland cement
are used, retain the last two sentences. Consult EM
1110-2-2000 to fill in the blanks and to select the
appropriate w/c.
**************************************************************************
Maximum water-cement ratio (w/c) for normal weight concrete shall be as
follows:
WATER-CEMENT RATIO, BY WEIGHT
STRUCTURE OR PORTION OF STRUCTURE
[0.40]
[_____]
[0.45]
[_____]
[0.50]
[_____]
[0.55]
[_____]
[_____]
[_____]
These w/c's may cause higher strengths than that required above for
compressive or flexural strength. The maximum w/c required will be the
equivalent w/c as determined by conversion from the weight ratio of water
to cement plus pozzolan, silica fume, and ground granulated blast furnace
slag (GGBF slag) by the weight equivalency method as described in ACI 211.1.
In the case where silica fume or GGBF slag is used, the weight of the
silica fume and GGBF slag shall be included in the equations of ACI 211.1
for the term P which is used to denote the weight of pozzolan.
SECTION 03300A
Page 17
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