Grade Of Concrete
Concrete is generally graded according to its compressive strength as per IS-156,2000, there are fifteen grades (M10 to M80) of concrete in the designation of concrete mix, the letter M refers to the concrete mix and the number refers to the specified characteristic strength of concrete at 28 days expressed in MPa.
The grade M10, M15, M20 are term as ordinary concrete.
The grade M25, M30, M35, M40, M45, M50, and M55 are termed as standard concrete.
The grades M60, M65, M70, M75, and M80 are termed as high strength concrete.
The Concrete of Grade M10
The concrete of grades M10 or lower is suitable for the lean concrete base, simple foundation, foundation of masonry walls and other simple works.
The Concrete of Grade M20
The concrete of grade M20 or higher is suitable for reinforced concrete works.
The Concrete of Grade M30
The concrete of grade M30 or higher is suitable for pre-stressed concrete works.
For Concrete in Seawater
For concrete in seawater or exposed directly along sea coast shall be at less M20 grade in the case of PCC concrete and M30 in the case of RCC works.