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.