Grade of concrete – Its 3 Types and Mix ratios

The designation of concrete according to its compressive strength is called the grade of concrete and according to their compressive strength concrete grades are M10, M20 and M30.

The M stands for the mix design of concrete by the compressive strength and numerical value stands for the characteristic compressive strength of concrete in 28 days and the mix is the ingredient proportions which are fine aggregates, coarse aggregate, and cement.

Based on structural design requirements the grade of concrete construction is selected and there are two types of concrete mixes, design mix & nominal mix.

The grades of concrete are converted into mix proportions consider for M20 concrete mix proportion will be 1: 1.5: 3 (cement, sand and coarse aggregates).

Suitable Concrete Grade For Construction:

Based on structural design requirements the grade will be selected and there are two types of concrete mixes, design mix & nominal mix.

For the small scale construction and small residential buildings where the concrete composition is not high nominal concrete is used and against various quality control problems occurring during concrete construction nominal mix take care of safety factor.

During material selection, mixing, transporting and placement of concrete use of design mix requires good quality and from various lab tests mix proportions are obtained and the design mix is created. If large scale concrete construction is carried out design mix concrete offers mix proportions based on locally available material and thus used in the large scale concrete construction.

So, on structural requirements, the suitable grade of concrete is selected and for small scale construction nominal mixes for a grade will like M15, M20 and M25 are used.

Types Of Concrete Grades:

There are many types of grades, regular types are M15, M20 and M25, etc and M15 is used for plain cement concrete work and M20 grade is used for the reinforced concrete construction.

There are following classifications of concrete grades such as;

1. Normal
2. The standard and,
3. High strength concrete grade

1: Normal Grade Of Concrete:                                            

Uses Of Normal Grades Of Concrete:

M5 Grade:

The application and use of M5 grade are to prevent the direct contact of foundation concrete from the soil and to provide the uniform surface of the foundation.

7.5 Grade:

The M7.5 grade provides the same application and uses as M5 grade which is to prevent to prevent the direct contact of foundation concrete from the soil and to provide the uniform surface of the foundation.

M10 & M15 Grade:

The M10 & M15 grades is used in the construction of concrete roads, leveling courses, bedding for footing, etc.

M20:

M20  is used in the construction of footing, columns, slabs, and beams, etc.

2: Standard Grade Of Concrete:

Uses Of Standard Grades:

M25, M30 and M35 Grades Of Concrete:

M25, M30 & M35 grades of concrete are used in the construction of footing, columns, slabs, and beams, etc and used as reinforced cement concrete (RCC).

M40 Grade:

M40 is used in the slabs, beams, columns, footing, and prestressed concrete, etc.

M45 Grade:

M45 is used in pressurized beams, RCC columns, runways, concrete roads, and pressurized concrete girders, etc.

3: High Strength Concrete Grades:

Uses Of High Strength Grades Of Concrete:

M50 Grade:

M50  is used in pressurized beams, runways, concrete roads, RCC columns etc.

M55 Grade:

M55 is used in pier and pressurized concrete girders.

M60 & M70 Grade Of Concrete:

M60 & M70 grades of concrete are used in RCC work where high compressive strength is required such as high rising buildings and long bridges etc.