of trial mixture should be basis for QC.
**************************************************************************
Trial batches and testing requirements for concrete shall be the
responsibility of the Contractor. Samples of approved aggregates shall be
obtained in accordance with the requirements of ASTM D 75. Samples of
materials other than aggregate shall be representative of those proposed
for the project and shall be accompanied by manufacturer's test reports
indicating compliance with applicable specified requirements. Trial
mixtures having proportions, slumps, and air content suitable for the work
shall be made based on ACI 211.1. The maximum water-cement ratio required
in the paragraph MAXIMUM WATER-CEMENT RATIO will be converted to a weight
ratio of water to cement plus pozzolan or GGBFS by mass equivalency as
described in ACI 211.1. In the case where GGBFS is used, the mass of the
slag shall be included in the equation for the term P, which is used to
denote the mass of pozzolan. Trial mixtures shall be proportioned for
specified slump and air content. The temperature of concrete in each trial
batch shall be reported. If a chemical admixture is used, slump loss
versus time in each trial batch shall be reported. For each trial mixture,
at least three test cylinders for each test age shall be made and cured in
accordance with ASTM C 192/C 192M. They shall be tested at 7 and 28 days
in accordance with ASTM C 39/C 39M, or if a pozzolan is used, they shall be
tested at 7, 28, and 90 days. Results of these compressive strength tests
shall be submitted but will be used only for quality control purposes. All
results of mixture proportioning studies shall be submitted at least 10
days prior to commencing concrete placement.
PART 3
EXECUTION
3.1
EQUIPMENT
3.1.1
Capacity
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NOTE: Experience has shown that to reduce problems
associated with placement rates, the minimum
capacity should be 76.5 cubic meters per hour (100
cubic yards per hour).
**************************************************************************
The batching and mixing equipment shall have a capacity of at least [_____]
cubic meters yards per hour.
3.1.2
Batch Plant
Batching Plant shall conform to the requirements of NRMCA CPMB 100 and as
specified; however, rating plates attached to batch plant equipment are not
required.
3.1.2.1
Batching Equipment
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NOTE: Refer to the appropriate DM to choose the
appropriate alternates.
**************************************************************************
The batching controls shall be [partially automatic], [semiautomatic], [or]
[automatic]. [The semiautomatic batching system shall be provided with
interlocks such that the discharge device cannot be actuated until the
SECTION 03373
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