# How to Carry out Concrete Cubes Sampling as per IS 456? Reading time: 1 minute

The compressive strength test is one of the most important tests performed on concrete. This test gives a fair idea about the quality of the concrete that is being poured at the site. While conducting this test, the major question that emerges in front of a site engineer is - How many Concrete Cubes to Cast?

In this article, we will discuss how to determine the number of samples to cast as per IS 456 with examples.

## Concrete Cubes Sampling

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

Note:
The number of samples mentioned in the table is for a 28 days compressive strength compliance requirement. Additional samples shall be cast to determine the strength of 7 days or at the time of striking the formwork as per the instruction of the engineer-in-charge.

## Example 1:

Quantity of Concrete: 14 m3

The prescribed number of samples for 14 m3 of concrete as per the above table is 2 samples (6 cubes)

Therefore, 2 samples (6 cubes) from each batch of 7 m3 shall be cast for 28-day testing and an additional 1 sample (3 cubes) shall be cast for 7-day testing.

## Example 2:

Quantity of Concrete: 220 m3

The prescribed number of samples for 220 m3 of concrete as per the above table shall be:

= 4 + 1 + 1 + 1 + 1 Samples
= 8 Samples
(4 samples up to 50 m3, 1 sample for 50 - 100 m3, 1 sample for 100 - 150 m3, 1 sample for 150 - 200 m3 and 1 sample for 200 - 220 m3)

Therefore, 8 samples (32 cubes) from each batch shall be cast for 28-day testing and an additional 2 samples (6 cubes) shall be cast for 7-day testing as per the engineer in-charge.