Grade of concrete

Concrete is the homogeneous mixture of cement or lime, sand, aggregate and water with their proportion. The cement used in concrete is called cementing material. The sand used in the concreting is fine aggregate. The aggregate used in concreting is obtained either from stone or from over bond bricks. When the concrete mixture is allowed to cure, hard mass is formed. Grade of concrete is given by:

grade of concrete

Grade of concrete

Concrete Grade Mix Ratio (cement : sand : aggregates) Compressive Strength
MPa (N/mm2) psi
Normal Grades of Concrete
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

In the grade of concretes like M10, M20, M30, etc. “M” stands for Mix of the ratio of cement:sand: aggregate and 10/20/30 Stands for Compressive Strength.

Concrete less than M20 grade should not be used in the RCC work as per code IS 456:2000.

 

Different grade of concrete with applications:

Normal Grade of Concrete

a. M5 Grade 

– Mixing Ratio is 1:5:10 ( 1 part of cement, 5 parts of sand and 10 parts of aggregate).

– Compressive strength is 5MPa.

– Used in foundation bed to prevent direct contact between soil and foundation concrete.

b. M7.5 Grade

– Mixing Ratio is 1:4:8 ( 1cement part: 4 sand part: 8 aggregate part).

– Its compressive strength is 7.5 MPa.

-Used in foundation bed to prevent direct contact between soil and foundation concrete. (same as M5)

c. M10 Grade

– Mixing Ratio is 1:3:6 ( 1cement part: 3sand part: 6 aggregate part).

– Its compressive strength is 10MPa.

– Used in the base of footing, construction of levelling works, road construction, etc.

d. M15 Grade

– Mixing Ratio is 1:2:4 ( 1cement part: 2 sand part: 4aggregate part).

– Its compressive strength is 15 MPa.

– Used as Plain cement concrete ( PCC).

– Used in the base of footing, construction of levelling works, road construction, etc.

e. M20 Grade

– Mixing Ratio is 1:1.5:3 ( 1cement part: 1.5 sand part: 3aggregate part).

– Its compressive strength is 20 MPa.

– Used as Reinforced Cement Concrete(RCC).

– Used for construction of slabs,beams,columns,etc.

Standard Grade of Concrete

a. M25 Grade 

– Mixing Ratio is 1:1:2 ( 1cement part: 1 sand part:2aggregate part).

– Its compressive strength is 25 MPa.

– Used as Reinforced Cement Concrete(RCC).

– Used for construction of slabs,beams,columns,etc.

b. M30 Grade

-M-30 Mix Designs as per IS-10262-2009

– Used as Reinforced Cement Concrete(RCC).

– Used for construction of slabs,beams,columns,etc.

c. M35Grade

–  M-35 Mix Designs as per IS-10262-2009

– Used as Reinforced Cement Concrete(RCC).

– Used for construction of slabs,beams,columns,etc.

d. M40 Grade

–  M-40 Mix Designs as per IS-10262-2009

–  Used as Prestressed Concrete.

– Used for construction of slabs,beams,columns,etc.

e. M45 Grade

–  M-45 Mix Designs as per IS-10262-2009

–  Used as Reinforced Cement Concrete (RCC)

–  Used in the followings:

i. Runways

ii. Concrete Roads (PQC)

iii. Pressurized Concrete Girders

iv. Pressurized beams

v. RCC Columns

f. M50 Grade

–  M-50 Mix Designs as per IS-10262-2009

–  Used as Reinforced Cement Concrete (RCC)

–  Used in the followings:

i. Runways

ii. Concrete Roads (PQC)

iii. Pressurized Concrete Girders

iv. Pressurized beams

v. RCC Columns

g. M55 Grade

–  M-55 Mix Designs as per IS-10262-2009

–  Used in the Pressurized Concrete Girders.

–  Used in the Pressurized Concrete Piers.

High Strength Grade of Concrete

M60 & M80 Grade of Concrete

-They are used in the  following:

a. Construction of high rise buildings, spillways of dams, long-span bridges, etc.

b. It can be used in the work where the environment is quite aggressive.

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