Estimation of the Material for Concrete
This article will cover the calculation of material needed for concrete, including cement, fine aggregate, and aggregates for the different mix proportions like 1:2:4, 1:1.5:3, 1:1:2. The quantities can be determined using two different methods. Estimation of the Material for Concrete.
The RCC (Reinforced Cement Concrete) comprises of beams, slabs, columns, and foundations, among other structural elements, based on the classification of the structure. To determine the volume of the concrete required for the concrete structure, one can add up the volumes of each structural member or the individual parts of the members.
For rectangular or square members, the volume can be calculated by multiplying the length, breadth, and height (thickness). Different formulas should be used for members with the different shapes.
To estimate the materials needed for the concrete, the following materials should be calculated as listed below:
W =Mass of the water
C = Mass of the cement
Fa = Mass of the fine aggregates
Ca = Mass of the coarse aggregates
The air content has been ignored in calculation.
Methods for the estimation of the concrete materials:
There are 2 methods for the estimation of materials for the concrete.
- First Method
- Second Method
First Method.
There are few steps for the estimation of the materials for concrete these steps are given below:
Wet Volume of the structure
Convert wet volume into dry
Qty of the cement
Qty of the sand
Qty of the coarse aggregate
Qty of the water
To calculate the materials for the concrete let’s take an example.
To determine the materials required for concrete M15 (1:2:4) in a slab with a length of 10m, breadth of 5m, and a thickness or depth of 0.125m, we first need to calculate the wet volume of the structure.
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The wet volume can be found by multiplying length, breadth, and the thickness of the slab:
Wet Volume = Length × Breadth × Thickness
Wet Volume = 10m × 5m × 0.125m
Wet Volume = 6.25 m3.
Convert Wet Volume into the Dry
To find out the dry volume simply multiply the wet volume with the value that is “1.54” it will convert into the dry volume.
Wet volume = 6.25 m3
To convert wet volume into the dry volume
The Dry volume = 6.25 × 1.54
The Dry Volume = 9.625 m3
Quantity of the Cement
To find the qty of the cement the following steps should be used that is the given below:
- Sum of the concrete ratio or proportion
- Density of the cement
We find the qty of the cement for the M15 concrete in which ratio of this concrete is 1:2:4 so “One” is the cement “Two” is the sand while “Four” is the coarse aggregate.
sum of concrete ratio = 1+2+Four
sum of concrete ratio = Seven
Density of the cement is 1440 kg/m3
Cement Qty = (Cement Part / sum of the ratio) × Dry Volume × cement Density
Cement Qty = (one / seven) × 9.625 ×1440
Cement Qty = 1980 kg
To convert kilogram into the bags simply divide the kilogram by 50 because one bag cement contains 50 kilograms.
Cement Qty = 1980/50
Cement Qty = 39.6 say Forty bags
Qty of The Sand:
The qty of the sand can have calculated as the method for the estimation of the qty of the sand is given below:
We find the quantity of sand for the M15 concrete in which ratio of this concrete is 1:2:4 so “One” is the cement “Two” is the sand while “Four” is the coarse aggregate.
Sum of concrete ratio = 1+2+4
sum of concrete ratio = Seven
Qy of the Sand = (Sand Part / sum of the ratio) × Dry Volume
Qty of the Sand = (Two / Seven) × 9.625
Qty of the Sand = 2.75 m3
Qty of the Coarse Aggregate.
The estimation of the qty of the coarse aggregate is given below:
We find the qty of the coarse aggregate for the M-15 concrete in which ratio of the concrete is 1:2:4 so “One” is cement “Two” is sand while “Four” is coarse aggregate.
sum of concrete ratio = 1+2+4
sum of concrete ratio = Seven
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Qty of the Coarse Aggregate = (coarse aggregate Part / sum of the ratio) × Dry Volume
Qty of the Sand = (Four / Seven) × 9.625
Qty of the Sand = 5.5 m3
Water Cement Ratio
If water cement is not given by designer, we can assume the water cement ratio is According to the IS 10262 (2009). Here the value of the water cement ratio is 0.50
The Required Amount of Water = W/C Ratio X weight of Cement(kg)
Weight of the cement = No. of the bags x 50
Where one bag of the cement contain 50 kg cement
Weight of the cement = 40 x 50
Weight of the cement = 2000
Required Amount of the Water = 0.50 X 2000
Required Amount of the Water = 1000 liters
Second Method:
- Volume of the structure
- Multiply value of the table with volume
S.No | Concrete Mix | Cement | Sand(m3) | Coarse Aggregate (m3) | ||
cubic meter(m3) | Number of Bags | By weight(Kg) | ||||
| 1 | 1:6:12 | 0.08 | 2.2 | 110 | 0.48 | 0.95 |
| 2 | 1:5:10 | 0.09 | 2.6 | 130 | 0.47 | 0.94 |
| 3 | 1:4:8 | 0.12 | 3.4 | 170 | 0.46 | 0.91 |
| 4 | 1:3:6 | 0.15 | 4.4 | 220 | 0.45 | 0.91 |
| 5 | 1:2.5:5 | 0.18 | 5.2 | 260 | 0.45 | 0.89 |
| 6 | 1:2:4 | 0.22 | 6.4 | 320 | 0.44 | 0.87 |
| 7 | 1:1.5:3 | 0.28 | Eight | 400 | 0.42 | 0.84 |
| 8 | 1:1:02 | 0.39 | 11.2 | 560 | 0.39 | 0.78 |
To calculate the materials for the concrete let’s take an example
Example.
The beam having length ten m breadth 0.3 m and the thickness or depth 0.5m. the water cement ratio is 0.50 find the materials for the concrete M15 (1:2:4)?
Qty of the Cement
To find the qty of the cement the following steps should be used that is the given below:
- Find Volume of structural member
- Select value for the concrete Mix
- Multiply Selected Value of the concrete mix with Volume
Volume = Length × Breadth × Thickness
Volume = 10 × 0.3 × 0.5
Volume = 1.5 m3
We find the qty of the cement for the M15 concrete in which table value for the cement is given for Kilogram, cubic meter (m3) and in the bags. It means that we can find the qty of the cement either in kilogram, cubic meter (m3) and also in the bags just multiply the value of the volume with the table values.
Cement Qty in the Kilogram:
Cement can find in the kilogram just multiply the table value with the volume
Cement Qty = value of table × Volume
Cement Qty = 320 × 1.5
Cement Qty = 480 kg
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Cement Qty in the Bags
Cement can find in the bags just multiply the table value with the volume
Cement Qty = value of table × Volume
Cement Qty = 6.4 × 1.5
Cement Qty = 9.6 bags
Cement Qty in the volume(m3):
Cement can find in the volume (m3) just multiply the table value with volume the of the structural member.
Cement Qty = value of the table × Volume
Cement Qty = 0.22 × 1.5
Cement Qty = 0.33 (m3)
To convert the kilogram into bags simply divide the kilogram by 50 because one bag cement contains 50 kilograms.
Cement Qty = 1980/50
Cement Qty = 39.6 say 40 bags
Quantity of the Sand (m3):
Sand can find in the volume (m3) just multiply the table value with volume the of the structural member.
Qty of the Sand = value of the table × Volume
Qty of the Sand = 0.44 × 1.5
Qty of the Sand = 0.66 (m3)
The qty of the sand can have calculated as the method for the estimation of the qty of the sand is given below:
We find the qty of the sand for the M15 concrete in which ratio of this concrete is 1:2:4 so “One” is the cement “two” is the sand while “Four” is the coarse aggregate.
sum of the concrete ratio = 1+2+4
sum of the concrete ratio = seven
Qty of the Sand = (Sand Part / sum of ratio) × Dry Volume
Qty of the Sand = (2 / 7) × 9.625
Qty of the Sand = 2.75 m3
Qty of the Coarse Aggregate:
The Coarse aggregate can find in the volume (m3) just multiply the table value with volume the of the structural member.
Qty of the Coarse Aggregate = value of table × Volume
Qty of the Coarse Aggregate = 0.88 × 1.5
Qty of the Coarse Aggregate = 1.32 (m3)
Water Cement Ratio.
If the water cement is not given by designer, we can assume the water cement ratio is According to IS 10262 (2009). Here the value of the water cement ratio is 0.50
The Required Amount of Water = W/C Ratio X weight of Cement(kg)
Required Amount of the Water = 0.50 X 480
Required Amount of the Water = 240 liters
Note
If u want to calculate the qty of the material and the dimension is the given in foot or inches etc. simply convert these units (unit conversion) in the meter and then calculate the materials in these methods which I have discuss in the article.
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