The Minimum grade of concrete can be made using nominal mix concrete shall be

Explanation:

Concrete mix design:

• Concrete mix design is classified as nominal mix design and the design mix

Nominal mix design:

• This is a very rough method of concrete mix design which gives wrong translations of concrete grades.
• IS 456:2000 provides a more precise nominal mix proportion for M5, M7.5, M10, M15, and M20 grades of concrete in terms of the total mass of aggregates, proportions of fines to coarse aggregates, and volume of water to be used per 50 kg of cement.
• Nominal mix concrete can only be used in ordinary concrete constructions involving concrete grades not higher than M20.
• For higher grades of concrete, design mix concrete is adopted.

Design mix concrete:

• Design mix concrete is based on the principle of "mix design" and is always preferred over the nominal mix of concrete.
• It yields concrete of desired quality and is more economical than the nominal mix.
• The IS recommendations of the mix design are given in IS 10262:1982 and SP 23:1982.