GRADE OF CONCRETE AND ITS COMPRESSIVE STRENGTH

What is Grade of Concrete?

Grade of concrete is defined as the minimum strength the concrete must posses after 28 days of construction with proper quality control. Grade of concrete is denoted by prefixing M to the desired strength in MPa. For example, for a grade of concrete with 20 MPa strength, it will be denoted by M20, where M stands for Mix.

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CONCRETE GRADE MIX RATIO (CEMENT : SAND : AGGREGATES) COMPRESSIVE STRENGTH
MPA (N/MM2) PSI
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

Choosing the right concrete grade for the construction job:

So what can these grades be used for and which is best for the job at hand? Below is a list of a few of the initial concrete grades and what they are best used for.

C10

Used for: Patio slabs, pathways and non-structural work

Type: Domestic & commercial use

C15

Used for: Pavement kerbs and floor blinding

Type: Domestic & Commercial

C20

Used for: Domestic floors and foundations (where the weight of structure will be lighter). Also good for workshop bases, garages, driveways and internal floor slabs.

Type: Domestic

C25

Used for: Construction in all areas. Multi-purpose concrete mix, usually used for foundations.

Type: Domestic & Commercial

C30

Used for: Pathways and roadways (this is the lowest grade concrete mix that can be used for this purpose). More durable than the grades that have come before, and thus is much more weather-resistant and can take heavy road traffic.

Type: Commercial

C35

Used for: Commercial structures. This heavy concrete mix is usually used for creating external walls and slabs, as well as for structural piling.

Type: Commercial

C40

Used for: Commercial construction sites, creating foundations and beams for structural support and roads. The most durable in this list, C40 can withstand chemical corrosion also, so is frequently used on farms where slurry could corrode structures, or in septic tanks.

Type: Commercial

We hope you found this guide useful, and if you are interested in learning more, visit our blog for more information on the concrete types available to you.