## What Is Grade of Concrete

Grade of concrete, simply put, is the strength of concrete measured after 28 days of construction. By the composition and strength of the concrete, the grades of concrete are defining. For the initial construction, the minimum strength of concrete should have followed at 28 days.

The grade of concrete construction is based on structural integrity and type of concrete mix. Nominal mix of concrete is generally used in small scale construction, whereas design mix is used in large scale constructions.

Here is a table defining different types of concrete grades along with the concrete mix ratio, and compressive strength. The grade of concrete is expressed in the measurement MPa. Where the M is stand for mix and the MPa expressed the overall strength of the concrete.

As an example for the M20 grade of concrete, Where the M stands for mix and 20 means the maximum compressive strength achieves by the concrete 20N/mm2 at 28 days. The size of the cube upon which the compressive strength test is done is 150 X 150 X 150 mm.

## The Different Types Grade of Concrete Is Below

GROUP | DESIGNATION | CHARACTERISTIC COMPRESSIVE STRENGTH Fck AT 28 DAYS |

ORDINARY CONCRETE | M 10 | 10 |

M 15 | 15 | |

M 20 | 20 | |

M 25 | 25 | |

M30 | 30 | |

M35 | 35 | |

STANDARD CONCRETE | M 40 | 40 |

M 45 | 45 | |

M 50 | 50 | |

M 55 | 55 | |

M 60 | 60 | |

M 65 | 65 | |

HIGH STRENGTH CONCRETE | M 70 | 70 |

M 75 | 75 | |

M 80 | 80 |

## Concrete Mix Ratio

The different grade of concrete and with the required grade in the constructions, the concrete mix ratio is different thatâ€™s are below-

### Grade of Concrete

- For the M5 grade of concrete the mix ratio (cement: sand: aggregate) is 1: 5: 10 and the compressive strength 5 MPa ( N/mm2 ) or 725 psi.
- For the M7.5 grade of concrete the mix ratio (cement: sand: aggregate) is 1: 4: 8 and the compressive strength 7.5 MPa ( N/mm2 ) or 1087 psi.
- And for the M10 grade of concrete the mix ratio (cement: sand: aggregate) is 1 : 3: 6 and the compressive strength 10 MPa ( N/mm2 ) or 1450 psi.
- For the M15 grade of concrete the mix ratio (cement: sand: aggregate) is 1 : 2: 4 and the compressive strength 15 MPa ( N/mm2 ) or 2175 psi.
- For the M20 grade of concrete the mix ratio (cement: sand: aggregate) is 1: 1.5 : 3 and the compressive strength 20 MPa ( N/mm2 ) or 2900 psi.

### The Standard Grade of Concrete

The Standard grade of concrete is below-

- For the M25 grade of concrete the mix ratio (cement: sand: aggregate) is 1 : 1: 2 and the compressive strength 25 MPa ( N/mm2 ) or 3625 psi.
- For the M30 grade of concrete the mix ratio (cement : sand: aggregate) is the design mix and the compressive strength 30 MPa ( N/mm2 ) or 4350 psi.
- And for the M35 grade of concrete the mix ratio (cement: sand: aggregate) is the design mix and the compressive strength 35 MPa ( N/mm2 ) or 5075 psi.
- For the M40 grade of concrete the mix ratio (cement: sand: aggregate) is the design mix and the compressive strength 40 MPa ( N/mm2 ) or 5800 psi.
- For the M45 grade of concrete the mix ratio (cement : sand: aggregate) is the design mix and the compressive strength 45 MPa ( N/mm2 ) or 6525 psi.

### High Strength Grade of Concrete-

The high strength grade of concrete is below-

- For the M50 grade of concrete the mix ratio (cement: sand: aggregate) is the design mix and the compressive strength 50 MPa ( N/mm2 ) or 7250 psi.
- For the M55 grade of concrete the mix ratio (cement: sand: aggregate) is the design mix and the compressive strength 55 MPa ( N/mm2 ) or 7975 psi.
- And for the M60 grade of concrete the mix ratio (cement: sand: aggregate) is the design mix and the compressive strength 60 MPa ( N/mm2 ) or 8700 psi.
- For the M65 grade of concrete the mix ratio (cement: sand: aggregate) is the design mix and the compressive strength 65 MPa ( N/mm2 ) or 9425 psi.
- For the M70 grade of concrete the mix ratio (cement : sand: aggregate) is the design mix and the compressive strength 70 MPa ( N/mm2 ) or 10150 psi.

## Type of Concrete Mix

Genarally there are two types of concrete mix thatâ€™s are below-

### Nominal Mix

In which mix the below-grade of concrete are used thatâ€™s that is called nominal mix. The grads are-

- M5 grade and the ratio is 1: 5: 10.
- M7.5 grade and the ratio is 1 : 4: 8.
- M10 grade and the ratio is 1 : 3: 6.
- M15 grade and the ratio is 1 : 2: 4.
- M20 grade and the ratio is 1: 1.5 : 3.

### Design Mix

In which mix M25, M30, M35, M40, M45, M50, M55, M60, M65, and M70 grade of concrete are used thatâ€™s is called design mix.

## Different Types of Concrete Grade with Concrete Mix Ratio and Compressive Strength

### Normal Concrete Grade

- For the M5 grade of concrete the mix ratio (cement : sand : aggregate) is 1 : 5 : 10 and the compressive strength 5 MPa ( N/mm2 ) or 725 psi.
- For the M7.5 grade of concrete the mix ratio (cement : sand : aggregate) is 1 : 4 : 8 and the compressive strength 7.5 MPa ( N/mm2 ) or 1087 psi.
- And for the M10 grade of concrete the mix ratio (cement : sand : aggregate) is 1 : 3 : 6 and the compressive strength 10 MPa ( N/mm2 ) or 1450 psi.
- For the M15 grade of concrete the mix ratio (cement : sand : aggregate) is 1 : 2 : 4 and the compressive strength 15 MPa ( N/mm2 ) or 2175 psi.
- For the M20 grade of concrete the mix ratio (cement : sand : aggregate) is 1 : 1.5 : 3 and the compressive strength 20 MPa ( N/mm2 ) or 2900 psi.

### Standard Concrete Grade

- For the M25 grade of concrete the mix ratio (cement : sand : aggregate) is 1 : 1 : 2 and the compressive strength 25 MPa ( N/mm2 ) or 3625 psi.
- For the M30 grade of concrete the mix ratio (cement : sand : aggregate) is design mix and the compressive strength 30 MPa ( N/mm2 ) or 4350 psi.
- And for the M35 grade of concrete the mix ratio (cement : sand : aggregate) is design mixÂ and the compressive strength 35 MPa ( N/mm2 ) or 5075 psi.
- For the M40 grade of concrete the mix ratio (cement : sand : aggregate) is design mix and the compressive strength 40 MPa ( N/mm2 ) or 5800 psi.
- For the M45 grade of concrete the mix ratio (cement : sand : aggregate) is design mix and the compressive strength 45 MPa ( N/mm2 ) or 6525 psi.

### High Strength Concrete Grade

- For the M50 grade of concrete the mix ratio (cement : sand : aggregate) is design mix and the compressive strength 50 MPa ( N/mm2 ) or 7250 psi.
- For the M55 grade of concrete the mix ratio (cement : sand : aggregate) is design mix and the compressive strength 55 MPa ( N/mm2 ) or 7975 psi.
- And for the M60 grade of concrete the mix ratio (cement : sand : aggregate) is design mixÂ and the compressive strength 60 MPa ( N/mm2 ) or 8700 psi.
- For the M65 grade of concrete the mix ratio (cement : sand : aggregate) is design mix and the compressive strength 65 MPa ( N/mm2 ) or 9425 psi.
- For the M70 grade of concrete the mix ratio (cement : sand : aggregate) is design mix and the compressive strength 70 MPa ( N/mm2 ) or 10150 psi.

## Uses of Different Grades of Concrete

The many uses of different grade of concrete is below-

### Normal Grade of Concrete

- In the normal grade of concrete M5, M10, M15 are generally used plain cement concrete (PCC) work for bedding for footing or leveling courses, etc.
- The M20 grade of concrete is used for reinforcement cement concrete (RCC) work such as column, beam, slab, and footing, etc.

### The Standard Grade of Concrete

- The M25, M30, M35 grades are used for reinforcement cement concrete (RCC) as footing columns, slabs, beams, foundations, etc.
- For the pre-stressed concrete work, M4O grade is used for beams, slabs, columns, footing, etc.
- For the pre-stressed concrete girder, runway, concrete roads pre-stressed beams, RCC columns M45, and M50 are used.
- For the piers and pre-stressed concrete girder, the M55 grade of concrete is used.

### High Strength Concrete

Where the high compressive strength is required such as long-span bridge, high rise building, ultra-thin white topping, coastal construction, spillways of dams, etc. there we used M60, M65, and M70 grade of concrete are used.

## FAQ on the Grades of Concrete

### What is the grade of concrete?

The grade of concrete is a measure of its strength, determined after 28 days of curing. It indicates the compressive strength of the concrete mix and is expressed in MPa (Mega Pascals).

### How is the grade of concrete expressed?

The grade of concrete is expressed as “M” followed by a number. For example, M20 concrete has a compressive strength of 20 MPa.

### What does “M” stand for in concrete grades?

The “M” in concrete grades stands for “Mix”. It denotes the mix ratio of cement, sand, and aggregate in the concrete.

### What are the different types of concrete grades?

Concrete grades are categorized into:

**Ordinary Concrete:**M10, M15, M20, M25, M30, M35**Standard Concrete:**M40, M45, M50, M55, M60, M65**High Strength Concrete:**M70, M75, M80

### What is the concrete mix ratio for M20 grade concrete?

The mix ratio for M20 grade concrete is 1 part cement, 1.5 parts sand, and 3 parts aggregate.

### What is the compressive strength of M20 grade concrete?

The compressive strength of M20 grade concrete is 20 MPa or 2900 psi.

### What is the nominal mix and design mix in concrete?

**Nominal Mix:**Used for small-scale construction and involves fixed proportions of cement, sand, and aggregate (e.g., M5, M7.5, M10, M15, M20).**Design Mix:**Used for large-scale construction and involves specific mix proportions designed to achieve the desired strength (e.g., M25, M30, M35, M40, M45, M50, M55, M60, M65, M70).

### What are the uses of different concrete grades?

**Normal Grade Concrete (M5, M10, M15):**Used for plain cement concrete (PCC) work, bedding for footings, and leveling courses.**Standard Grade Concrete (M20, M25, M30, M35):**Used for reinforced cement concrete (RCC) work such as columns, beams, slabs, and footings.**High Strength Concrete (M40, M45, M50, M55, M60, M65, M70):**Used in structures requiring high compressive strength, such as long-span bridges, high-rise buildings, and coastal constructions.

### What is the significance of the cube size in compressive strength testing?

The cube size used for compressive strength testing is typically 150mm x 150mm x 150mm. This standard size helps ensure consistent and comparable results.

### Why is the compressive strength measured after 28 days?

The 28-day period is considered sufficient for the concrete to reach its maximum strength, providing a reliable measure of its compressive strength.