Number of cubes for concrete as per is code

 Number of cubes for concrete as per is code

The minimum frequency of sampling of concrete of the each grade shall be in accordance with the following

Quantity of concrete in the work in m3

Number of sample

1-5

1

6-15

2

16-30

3

31-50

4

51 and above

4 plus one additional sample for each additional 50m3

 

 

 Characteristic Compressive Strength Compliance Requirement:

Specified grade

Mean of the group of 4 non-overlapping consecutive test results in N/mm2

Individual test results in N/mm2

M-15

>= fck + 0.825 x established standard deviation

(rounded off to nearest 0.5 N/mm2)

or

fck + 3 N/mm2

whichever is greater

>=fck – 3 N/mm2

M-20 or above

>= fck + 0.825 x established standard deviation

(rounded off to nearest 0.5 N/mm2)

or

fck + 4 N/mm2

whichever is greater




>= fck – 4 N/mm2

Note : at least one sample taken form each shift where the concrete is provide of continuous production unit such as ready -mixed concrete plant ,frequency of sampling may be aggregate upon mutually by supply and porches.

Test Specimen 

There test Specimens shall be made for each sample for Testing at 28 days . additional samples may be required for various purpose such as to determine the strength of concrete at 7days or at the time of striking the formwork or to determine the duration of curing or to check the testing error. additional sample may also required for testing sample cured by accelerated methods as described in IS 9103 . The specimen shall be tested by described in is 516

The Results of Sample 

the test result of sample shall be average of strength of the three specimens. The individual variation should not be more then +-15percent of the average , if more test result of the sample are invalid .

mm2

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