Grade of Concrete IS 4562000

Grade of Concrete Table | Concrete Grade as per IS 456

I recently visited my construction site in India to check the quality of work on-site, material Quality, Construction Type and Grade of Concrete as well Steel Quality. When I first entered on site, I was confused because I asked the site engineer about different types of concrete grades and Mixes. But they don’t know exactly about the grade of the concrete. I explained to him in great detail. I will try to put it out for you here.

What is the Grade of Concrete?

Grades of concrete are defined by the strength and material composition of the concrete. The grade of concrete in construction is based on what result found after a cube test of size 150mm, 150mm and 150mm after 28 days of the compressive test.

For Example, M-25 shows the crushing strength of that cube having a size of 150 mm × 150 mm × 150 mm at 28 days is 25 N/mm2. The concrete grade is denoted by M10, M20, M30, and so on according to their compressive strength

The nominal mix of concrete is generally used in small-scale construction, whereas the design mix is used in large-scale construction. 

Concrete Grade as Per IS 456

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

indicates the proportion of materials used for making concrete  Cement: Sand: Aggregate (1:3:6) or Cement: Fine Aggregate: Coarse Aggregate. If we say M20 grade of concrete, it means that the concrete has 20 N/mm2 characteristic compressive strength at 28 days.

Following are the Concrete Grade with their Mix Proportions and Characteristics strength specified by IS 456:2000

GroupGrade DesignationConcrete Mix RatioCharacteristics Strength After 28 Days (N/mm2)
Ordinary ConcreteM 101:3:610
Standard ConcreteM251:1:225
M30Design Mix30
M35Design Mix35
M40Design Mix40
M45Design Mix45
M50Design Mix50
M55Design Mix55
High Strength ConcreteM60Design Mix60
M65Design Mix65
M70Design Mix70
M75Design Mix75
M80Design Mix80

 The Grade of Concrete selection Depends on the Uses

Grade of ConcreteMix ProportionUses
M101:3:6PCC Foundation
M151:2:4PCC Roadwork
M201:1.5:3Normal Concrete Work
M251:1:2Reinforced concrete work
M30Design MixHeavy Reinforced concrete/pre-cast
M35Design MixPre-stressed/pre-cast concrete
M40Design MixHeavy Reinforced Work Bridge, High Rise buildings Column
M45Design MixVery heavy reinforced concrete/pre-cast/prestressed
M50Design MixVery heavy reinforced concrete/pre-cast/prestressed
M60Design MixIn very sensitive cases like the pier in Sea where salt water direct affects.

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