Here after is the specification for concrete aggregate testing in a hi-rise building construction.
General
Samples of the fine and coarse
aggregates approved by the Engineer shall be kept on the Site and shall
give a fair indication of the approved quality of the aggregate for
comparison with the aggregate delivered during the course of the works.
Should a sample fail to comply with any
of tests, the Engineer may at his own discretion reject the batch from
which sample was taken, or order it to be washed and/or screened, or
permit such to be used with variations in the proportions of the
concrete mixes specified, all a the Contractor’s expense. Any batch of
aggregate rejected by the Engineer shall be removed from the site
forthwith and replaced entirely at the Contractor’s expense.
All sample and testing of aggregates shall be carried out in accordance with ASTM C33.
Preliminary Aggregate Tests
As soon as the source of supply of
aggregate have been approved, the Contractor shall instruct the testing
agency to carry out the following tests for compliance with
“Specification of Concrete Aggregates” (ASTM C33).
- Sieve analysis
- Tests for clay, silt and dust content
- Tests for organic impurities
- Tests for salt content (chloride and sulfate ions)
The results of these tests shall be
submitted for approval as soon as available. Test (1) and (2) with tests
for the moisture content of each aggregate shall be carried out on the
sample used for each trial mix.
Testing sampling of Aggregates
The contractors shall carry out such
tests on aggregate samples as are necessary for the production of the
specified concrete. The minimum incremental frequency of tests on each
type of concrete used for the works shall be:
- Sieve analysis: at least once weekly
- Moisture content: at least once weekly
- Tests for clay, silt and dust content: at least once fortnightlu
- Tests for organic impurities: at least once monthly
- Tests for salt content (chloride and sulfate ions): for every 500 cubic meters of concrete placed.
If for any reason the Engineer is not
satisfied with the works concrete, he may instruct the Contractor to
further increase the rate of sampling. Conversely, the rate of sampling
may be reduce by the Engineer when consistent high quality been well
established.
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