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# Calculation of materials in concrete

Before starting the numerical of calculation of materials in concrete, Learn these topics.

1 cub.m = 35.31 cub.feet

Density of Cement = 1400kg/cub.m

Density of Sand = 1450 kg/cub.m

Density of Aggregate =1500 kg/cub.m

Best starting the calculation of cement, sand and aggregate, Learn the below table:

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

## calculation of cement sand aggregate in concrete

### The calculation for 1 cub.m of Concrete

Note :
The volume of Dry concrete is 54%-57% of Wet volume of concrete.

i.e. Dry volume of concrete = 1.54 * Wet Volume of concrete

Given,

Wet Volume = 1 cub.m

Dry volume = 1.54 cub.m

( Dry concrete is 54%-57% more because there is loss during preparation and also concrete contracts after drying)

### For M20 Concrete

Cement : sand : aggregate = 1 : 1.5 : 3

Sum of all ratios = 1+1.5+3 = 5.5

## CEMENT

Quantity of cement = (cement ratio / Sum of ratios ) * Dry volume

= (1 / 5.5 ) * 1.54

= 0.28 cub. m

Density of cement = 1440 kg/cub.m

Mass of cement = Volume of cement * Density

= 0.28 * 1440

= 403.2 kg

We know that each bag of cement is of 50 kg

Number of cement bags = 403.5/50 = 8 bags

## SAND

Quantity of Sand = (Sand ratio / Sum of ratios ) * Dry volume

= (1.5 / 5.5 ) * 1.54

= 0.42 cub.m

Density of Sand = 1450kg/cub.m

Mass of sand = 0.42 * 1450 = 609 kg

## AGGREGATE

Quantity of aggregate = (aggregate ratio / Sum of ratios ) * Dry volume

= ( 3 / 5.5 ) * 1.54

= 0.84 cub. m

Density of Aggregate : 1500 kg/ cub. m

Mass of Aggregate : 0.84 *1500 = 1260 kg.

In this way, Calculation of materials in concrete can be done for all grades of concrete as required.