Grade of Concrete | Concrete Classification | Types of Concrete Mix | M25 Ratio | M30 Concrete Mix Ratio | M20 Ratio

3 min readNov 13, 2021

Grade of Concrete

Grades of concrete are defined by the concrete mix proportion and the minimum strength of concrete at end of 28 days curing period. The grade of concrete is can be known by calculating the compressive strength of concrete in Mpa, where M stands for mix and the MPa denotes the overall strength

There are different types of concrete mix which are based on concrete classification according to its compressive strength.

For making concrete we use cement, sand, aggregate, and water which are mixed with a certain ratio, and concrete is cast and put in a cube of 150 mm size and put in a water bath for 28 days and afterward, it is tested in a compression testing machine. The compressive stress result is known as the “grade of concrete”. It is expressed in N/mm²

The concrete grade is denoted by M10, M20, M30, and so on according to their compressive strength.

Concrete Grade As Per Indian Standards

The “M” refers to Mix and Number after M (M10, M20) Indicates the compressive strength of concrete after 28 days of curing and testing.

M indicates the proportion of materials like Cement: Sand: Aggregate (1:2:4) or Cement: Fine Aggregate: Coarse Aggregate.

If we mention M10 concrete, it means that the

concrete has 10 N/mm2 characteristic compressive strength at 28 days.

In the designation of concrete mix M to the mix and the number to the specified compressive strength of 150 mm size cube at 28 days, expressed in N/mm².

Concrete Grade Per British/European standards:

As per BS 8500–2 British/European standards the grade of concrete is denoted as C10, C15, C20, C25, etc., ‘C’ which means ‘Concrete Strength class’ and the number behind C refers to characteristic Compressive strength of Concrete in N/mm2 @ 28 days when tested with the 15 cm dia. & 30 cm height cylinder in a direct compression test.

The

grade of concrete is also denoted as C16/20, C20/25, C25/30, etc., which

means Concrete Strength Class

© the number behind C refers to Compressive strength of

Concrete in N/mm2 when tested with Cylinder / Cube.

Different mix

proportions of the materials used to make concrete namely

- Cement

- Coarse aggregate

- Fine aggregate

- Water

Result in

concretes with different properties.

Concrete Classification

Following are the Standard Concrete Grade with their Mix Proportions and Strength

Grades of Concrete Mix Ratio (Cement : Sand : Aggregates) Compressive Strength
MPa (N/mm2)psiLower Grade of ConcreteM5 1 : 5 :105 MPa725 psiM7.51 : 4 : 87.5 MPa1087 psiM101 : 3 : 610 MPa1450 psiM151 : 2 : 415 MPa2175 psiM201 : 1.5 : 320 MPa2900 psiStandard Grade of ConcreteM251 : 1 : 225 MPa3625 psiM30Design Mix30 MPa4350 psiM35Design Mix35 MPa5075 psiM40Design Mix40 MPa5800 psiM45Design Mix45 MPa6525 psiHigh Strength Grade of ConcreteM50Design Mix50 MPa7250 psiM55Design Mix55 MPa7975 psiM60Design Mix60 MPa8700 psiM65Design Mix65 MPa9425 psiM70Design Mix70 MPa10150 psi

The Selection of the Grade of Concrete Depends on the Situation and Uses:

Concrete Grade (N/mm2)Ratio Cement, Sand, and AggregatesUsage101:3:6PCC 151:2:4PCC 201:1.5:3Normal Construction Concrete251:1:2Reinforced concrete/precast30Concrete Mix DesignHeavy Reinforced concrete/pre-cast35Concrete Mix DesignPre-stressed/pre-cast concrete40Concrete Mix DesignVery heavy reinforced concrete/pre-cast/prestressed45Concrete Mix DesignVery heavy reinforced concrete/pre-cast/prestressed

Watch Video: What is Grade of Concrete and Different Types used in Construction

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