What is the proportion of concrete in M30 grade?

We all know that cement mixed with sand, stone/aggregate, and water will form a paste that can be used to bind building materials together. This paste is also called concrete. The strength of this concrete mix is ​​determined by the proportion in which these cement, sand, stone, or aggregates are mixed. Based on these ratios, different grades of concrete are available in the market. Some of them are M10, M20, M30, M35, etc. So, what does M10 or M20 mean or represent?

"M" means "mix". The mixture represents concrete with specified proportions of cement, sand and aggregate. And the number after "M" represents the compressive strength of that concrete mix in N/mm2 after 28 days. For example, for the M20 grade of concrete mix, it should have a compressive strength of 20 N/mm2 after 28 days.

concrete mix ratio table

Here is a standard chart table showing the different grades of concrete mix designs as well as their respective proportions of cement, sand, and aggregates required.

Grade of Concrete Ratio of Concrete Mixture Design

(cement: sand: aggregate)

M5             1:5:10

M7.5          1:4:8

M10           1:3:6

M15           1:2:4

M20           1:1.5:3

M25           1:1:2

M30          1:0.75:1.5

M35          1:0.5:1

M40          1:0.25:0.5

 

As you can see in the table above, in these standard mixing designs the amount of sand is always kept at half that of the aggregate. You can measure and maintain these ratios using buckets or some other standard cubes that can be easily used throughout the project. It is essential to maintain uniformity in each concrete mix prepared throughout the project. One of the important tasks of the site engineer/supervisor is to inspect and implement it.

Water Content Ratio in Concrete Mixture

Apart from the water content, the strength and workability of concrete is also determined to a large extent. The higher the water content, the higher the workability of the concrete (more fluid) although this reduces the strength of the concrete. But if you keep the water too low, the water's ability to work will also decrease. Therefore, it will be difficult to lay such concrete in the structure. The amount of water required for the same amount of concrete may vary for different grades of concrete. Therefore, during concrete mixing, balance has to be found in the construction site.