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Unformatted text preview: ncrete shall be operated on the work site. The
laboratory shall be fully equipped with apparatus for conductipg all the
usual physical tests for concrete.
The compression-testing machme shall
have a capacity of not less than 100 metric tonnes ( or 100 tons ) and shall
be capable of applying the test load at a uniform rate of application.
7.3 Test Records - A complete
An accurate daily record shall be
strength, water-cement ratio and
concrete placed in each part of the record shall be kept of all operations.
made of the location, mix, compressive
other physical data pertaining to the
structure. 7.3.1 The density, durability, imperviousness, generation and loss of
heat, expansion and other physical characteristics of the concrete shall be
tested as often as may be requi;ed to maintain the required properties.
7.4 Test Pieces-In
general, not less than one sample shall be taken
from approximately each 380 cu m ( or 500 cu yd ) of mass concrete and
from 190 cu m ( or 250 cu yd) of reinforced concrete placed and for each
class of concrete deposited in any one day’s run. Three cylinders or test
beams shall be made from each sample. The normal number of coutrol
specimens, however, may be changed at the discretion of the engineer-incharge. Samples for compression test shall be taken in the field in accordance with Appendix E of *IS : 456-1957.
All specimens shall be moulded
immediately after the sample.is taken.
They shall be stored in a protected
place under a moist condition at 27 f 2°C ( or 81 f 4°F ) without being
disturbed or moved for at least 24 hours after being zast.
7.4.1 For standard 15 x 30 cm ( or 6 x 12 in ) cylinders, all aggregate
having a maximum dimension of more than 4 cm ( or 14 in ) shall be removed by wet-screening the sample just before moulding the test pieces.
For large cylinders, the maximum size of aggregate left in the sample shall
not be more than one-fourth the diameter of the cylinder.
specimens as large as can be tested in the field laboratory shall be cast
without removing any aggregate.
Such specimens shall be tested to
establish the relation between unscreened and normally screened samples.
The corrective factor thus determined shall be applied to the tested strength
of screened specimens in recording the average daily unit strength of the
concrete placed in the structure.
7.4.2 For dams and other large structures, all field specimens .shall
be finally cured under m&t conditions at a constant temperature of
27 f 2°C ( or 81 f 4°F ) and at 85 percent relative humidity.
jobs where a moist room is not available, the specimens shall be cured in
accordance with the standard methodg of making znd storing compression
test specimens in the field.
l eared revisionin 196%
S 33 IS : 457 - 1957
‘i.4.3 Age of Specimeras - kegular tests shall be run at the age of 7
and 28 days, with occasional tests of representative
specimens at 14 days
and at 3. 6 and 12 months.
Compression 7.5 Tests 7.5.1 For compre...
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This document was uploaded on 10/01/2013.
- Fall '13