Grades of Concrete
Actually, what do we mean by grade of concrete.? Concrete grades are denoted by M10, M20, M30, according to their compressive strength. The “M” denotes Mix design of concrete followed by the compressive strength number in N/mm2, “Mix” is the respective ingredient proportions which are Cement: Sand: Aggregate Or Cement: Fine Aggregate: Coarse Aggregate.
Concrete Grade and Mix Ratio Table
As per IS 456:2000, the grades less than M20 should not be used in RCC works
| Concrete Grade | Mix Ratio | Compressive Strength | |
| MPa (N/mm2) | Psi | ||
| Normal Grade of Concrete | |||
| M5 | 1 : 5 : 10 | 5 MPa | 725 psi |
| M7.5 | 1 : 4 : 8 | 7.5 MPa | 1087 psi |
| M10 | 1 : 3 : 6 | 10 MPa | 1450 psi |
| M15 | 1 : 2 : 4 | 15 MPa | 2175 psi |
| M20 | 1 : 1.5 : 3 | 20 MPa | 2900 psi |
| Standard Grade of Concrete | |||
| M25 | 1 : 1 : 2 | 25 MPa | 3625 psi |
| M30 | Design Mix | 30 MPa | 4350 psi |
| M35 | Design Mix | 35 MPa | 5075 psi |
| M40 | Design Mix | 40 MPa | 5800 psi |
| M45 | Design Mix | 45 MPa | 6525 psi |
| High Strength Concrete Grades | |||
| M50 | Design Mix | 50 MPa | 7250 psi |
| M55 | Design Mix | 55 MPa | 7975 psi |
| M60 | Design Mix | 60 MPa | 8700 psi |
| M65 | Design Mix | 65 MPa | 9425 psi |
| M70 | Design Mix | 70 MPa | 10150 psi |
Grades of concrete, mainly classified in three categories as follows
1- Lean concrete
2- Ordinary grade of concrete
3- Standard grade of concrete
4- High strength concrete grades
1- Lean concrete
Lean concrete is a mix where the amount of cement is lower than the amount of liquid present in the strata.
M5 GRADE
Where M stands for Mix ration & 5 stands for compressive strength of a 150mm cube after 28 days of curing, expressed in N/mm2
The mix ratio is 1:5:10 (1 Cement, 5 Sand and 10 Aggregate)
Application/use: – To provide the uniform surface of the foundation concrete and to prevent the direct contact of foundation concrete from the soil.
M7.5 GRADE
The mix ratio is 1:4:8 (1 Cement, 4 Sand and 8 Aggregate)
Application/use: – To provide the uniform surface of the foundation concrete and to prevent the direct contact of foundation concrete from the soil.
2- Ordinary grade of concrete
M10 GRADE
The mix ratio is 1:3:6 (1 Cement, 3 Sand and 6 Aggregate)
It is used as PCC (Plain Cement Concrete)
Application/use: – It can be used in the construction of Levelling course, bedding for footing, concrete roads, etc.
M15 GRADE
The mix ratio is 1:2:4 (1 Cement, 2 Sand and 4 Aggregate)
It is used as PCC (Plain Cement Concrete)
Application/use: – It can be used in the construction of Levelling course, bedding for footing, concrete roads, etc.
M20 GRADE
The mix ratio is 1:1.5:3 (1 Cement, 1.5 Sand and 3 Aggregate)
It is used as RCC (Reinforced Cement Concrete)
Application/use: – It can be used in the construction of Slabs, beams, columns, footings, etc. (For mild exposure)
3- Standard grade of concrete
M25 GRADE
The mix ratio is 1:1:2 (1 Cement, 1 Sand and 2 Aggregate)
It is used as RCC (Reinforced Cement Concrete)
Application/use: – It can be used in the construction of Slabs, beams, columns, footings, etc.
M30 GRADE
It is used as RCC (Reinforced Cement Concrete)
Application/use: – It can be used in the construction of Slabs, beams, columns, footings, etc.
M-30 Mix Designs as per IS-10262-2009
M35 GRADE
It is used as RCC (Reinforced Cement Concrete)
Application/use: – It can be used in the construction of Slabs, beams, columns, footings, etc.
M-35 Mix Designs as per IS-10262-2009
M40 GRADE
It is used as RCC (Reinforced Cement Concrete)
Application/use: – Pre-stressed concrete, slabs, beams, columns, footings, etc. GRADE- M45 RCC e.g. Runways, Concrete Roads (PQC), Pressurized Concrete Girders, RCC Columns, pressurized beams
M-40 Mix Designs as per IS-10262-2009
GRADE- M50
It is used as RCC (Reinforced Cement Concrete)
Application/use: – Runways, Concrete Roads (PQC), Pressurized Concrete Girders, RCC Columns, pressurized beams
M-50 Mix Designs as per IS-10262-2009
GRADE- M55
It is used as RCC (Reinforced Cement Concrete)
Application/use: – Pressurized Concrete Girders and Pier
4- High strength concrete grades
M60 GRADE & M80 GRADE
It is used as RCC (Reinforced Cement Concrete)
Application/use:-
1- It can be used RCC work where high compressive strength is required such as high rise buildings, long span bridges, ultra-thin white topping etc.
2- Constructions in aggressive environment.
3- Spillways of dams, coastal construction of a passage for surplus water from a dam.
