Sampling Procedure:
A random sampling procedure is adopted to ensure that each concrete batch shall have a reasonable chance of being tested i.e., sampling is done to the entire period of concreting and cover all mixing units.
Frequency:
The minimum frequency of sampling of concrete of each grade shall be accordance with the following:
Quantity of concrete in the work (m3) | Number of samples |
1-5 | 1 |
6-15 | 2 |
16-30 | 3 |
31-50 | 4 |
51 and above | 4 Plus one additional sample for each additional 50 m3 |
Strength test of concrete (IS 456):
Samples from fresh concrete shall be taken and cubes shall be made and tested at 28 days. The test strength shall be the average of the strength of 3 specimen. The individual variation should not be more than 15 percent (+15% or -15%) of the average.