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free from vibration, under damp matting, sacks or other similar material
for 24 hours ± ½ hour from the time of adding the water to the other
ingredients. The temperature of the place of storage shall be within the
range of 22° to 32°C. After the period of 24 hours, they shall be marked
for later identification, removed from the moulds and, unless required
for testing within 24 hours, stored in clean water at a temperature of 24°
to 30°C until they are transported to the testing laboratory. They shall
be sent to the testing laboratory well packed in damp sand, damp sacks,
or other suitable material so as to arrive there in a damp condition not
less than 24 hours before the time of test. On arrival at the testing
laboratory, the specimens shall be stored in water at a temperature of
27° ± 2°C until the time of test. Records of the daily maximum and
minimum temperature shall be kept both during the period of the
specimens remain on the site and in the laboratory.
4. SECURING AND PREPARING SPECIMENS OF HARDENED
CONCRETE FOR COMPRESSION TEST
4.1 This clause deals with the procedure for securing and preparing
compression test specimens obtained from hardened concrete after the
concrete has been laid in position.
4.2 The test specimens shall be procured from hardened concrete
according to the method described in 4 of IS : 1199-1959*.
4.3 Cores to be tested for compression strength shall have ends that are
reasonably even, perpendicular to the axis and of the same diameter as
the body of the specimen. A core which, before capping, has a maximum
height of less than 95 percent of the diameter, or after capping, a height
less than its diameter shall not be used.
*Since revised. 9 IS : 516 - 1959
4.4 Capping — The ends of the specimen shall be capped before testing.
The material used for the capping shall be such that its compressive
strength is greater than that of the concrete in the core. Caps shall be
made as thin as practicable and shall not flow or fracture before the
concrete fails when the specimen is tested. The capped surfaces shall be
at right angles to the axis of the specimen and shall not depart from a
plane by more than 0.05 mm. The capping of specimens shall be carried
out as described in 2.11.
4.5 After checking for irregularities, the core shall be placed in water at
a temperature of 24° to 30°C for 48 hours before testing. The overall
height of the specimens, with capping shall be measured to the nearest
5. TEST FOR COMPRESSIVE STRENGTH OF CONCRETE
5.1 This clause deals with the procedure for determining the
compressive strength of concrete specimens.
5.2.1 Testing Machine — The testing machine may be of any reliable
type, of sufficient capacity for the tests and capable of applying the load
at the rate specified in 5.5. The permissible error shall be not greater
than ± 2 percent of the maximum load. The testing machine shall be
equipped with two steel bearing platens with...
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This document was uploaded on 10/01/2013.
- Fall '13