Grades of Concrete

The Indian Standard Code IS : 456-2000 specifies that the concrete mix proportion should be selected so as to ensure the workability of fresh concrete and durability of hardened concrete. The determination of the proportions of cement, aggregates and water to achieve the desired strength is made:

1. By designing the concrete by any well established method, or
2. By adopting nominal mix proportions.

The code specifies that the design mix should be preferred to nominal mix since the design mix concrete exhibits better performance compared to nominal mix concrete.

For reinforced concrete work, the most commonly used grades of concrete are M-20 to M-30. The revised Indian Standard Code IS : 456-2000 prescribes M-20 as the minimum grades of concrete for reinforced concrete work while M-10 and M-15 grades may be used for plain concrete constructions.