How To Estimate the Material for Concrete work

How To Estimate the Material for Concrete

In this Article we will discuss How To Estimate the Material for Concrete in which we will find the quantities of materials for concrete such as cement, fine aggregate and aggregates for production of required quantity of concrete of a mix proportions like 1:2:4, 1:1.5: 3, 1:1:2 can be calculated by 2 methods.

The Reinforced Cement Concrete consist of beams, slabs, columns & foundations etc. based on classification of structure. The volume of concrete need for concrete structure can be find by adding the volumes of each structural member or each parts of membrs.

The volume of a rectangular or square member can be find as length x Breadth x height (thickness). proper formla shall be used for different shapes of members.

For the estimation of materials for concrete following materials will be calculate that is given below

1. W =Mass of water

2. C = Mass of cement

3. Fa = Mass of fine aggregates

4. Ca = Mass of coarse aggregates

The air content has been ignored in the calculation.

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Methods for the estimation of concrete materials

There are two methods for the estimation of materials for concrete.

• 1^st Method
• 2^nd

1^st Method

There are few steps for the estimation of materials for concrete these steps are given below

1. Wet Volume of structure

2. Convert wet volume into dry

3. Quantity of cement

4. Quantity of sand

5. Quantity of coarse aggregate

6. Quantity of water

To calculate the materials for concrete let’s take an example

 

Example

A slab having length 10m breadth 5m and thickness or depth 0.125m. The water cement ratio is 0.50 find the materials for concrete M15 (1:2:4) .?

Wet volume of struture

First step is to find the volume of Structure or member

Volume = Length × Breadth × Thickness

Volume = 10 × 5 × 0.125

Volume = 6.25 m³

Convert Wet Volume into Dry

To find the dry volume simply multiply the wet volume with the value that is “1.54” it will convert into dry volume.

Wet volume = 6.25 m³

To convert wet volume into dry volume

Dry volume = 6.25 × 1.54

Dry Volume = 9.625 m³

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Quantity of Cement

To find the quantity of cement the following steps should be used that is given below:

• Sum of concrete ratio or proportion
• Density of cement

We find the quantity of cement for the M15 concrete in which ratio of this concrete is 1:2:4 so “1” is the cement “2” is the sand while “4” is the coarse aggregate.

sum of the concrete ratio = 1+2+4

sum of the concrete ratio = 7

Density of cement is 1440 kg/m³

Cement Quantity = (Cement Part / sum of ratio) × Dry Volume × cement Density                               

Cement Quantity = (1 / 7) × 9.625 ×1440

Cement Quantity = 1980 kg

To convert kilogram into bags simply divide the kilogram by 50 because 1 bag cement contains 50 kilograms.

Cement Quantity = 1980/50

Cement Quantity = 39.6 say 40 bags

 

Quantity of Sand

The Quantity of Sand can have calculated as the method for the estimation of the quantity of 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 “1” is the cement “2” is the sand while “4” is the coarse aggregate.

sum of the concrete ratio = 1+2+4

sum of the concrete ratio = 7

Quantity of Sand = (Sand Part / sum of ratio) × Dry Volume                           

Quantity of Sand = (2 / 7) × 9.625

Quantity of Sand = 2.75 m³

Quantity of Coarse Aggregate

The estimation of the quantity of coarse aggregate is given below

We find the quantity of coarse aggregate for the M15 concrete in which ratio of this concrete is 1:2:4 so “1” is the cement “2” is the sand while “4” is the coarse aggregate.

sum of the concrete ratio = 1+2+4

sum of the concrete ratio = 7

Quantity of Coarse Aggregate = (coarse aggregate Part / sum of ratio) × Dry Volume                              

Quantity of Sand = (4 / 7) × 9.625

Quantity of Sand = 5.5 m³

Water Cement Ratio

If water cement is not given by designer, we can assume the water cement ratio According to IS 10262 (2009). Here the value of water cement ratio is 0.50

Required Amount of Water = W/C Ratio X weight of Cement(kg)

Weight of cement = No. of bags x 50

Where 1 bag of cement contain 50 kg cement

Weight of cement = 40 x 50

Weight of cement = 2000

Required Amount of Water = 0.50 X 2000

Required Amount of Water = 1000 liters

 

2^nd Method

• Volume of structure
• Multiply value of 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	8	400	0.42	0.84
8	1:1:02	0.39	11.2	560	0.39	0.78

To calculate the materials for concrete let’s take an example

Example

A beam having length 10 m breadth 0.3 m and thickness or depth 0.5m. the water cement ratio is 0.50 find the materials for concrete M15 (1:2:4)?

Quantity of Cement

To find the quantity of cement the following steps should be used that is given below:

1. Find Volume of the structural member
2. Select value for concrete Mix
3. Multiply Selected Value of concrete mix with Volume

Volume = Length × Breadth × Thickness

Volume = 10 × 0.3 × 0.5

Volume = 1.5 m3

 

We find the quantity of cement for the M15 concrete in which table value for cement is given for Kilogram, cubic meter (m³) and in bags. It means that we can find find the quantity of cement either in kilogram, cubic meter (m³) and also in bags just multiply the value volume with the table values.

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Cement Quantity in Kilogram

Cement can find in kilogram just multiply the table value with volume

Cement Quantity = value of table × Volume

Cement Quantity = 320 × 1.5

Cement Quantity = 480 kg

Cement Quantity in Bags:

Cement can find in bags just multiply the table value with volume

Cement Quantity = value of table × Volume

Cement Quantity = 6.4 × 1.5

Cement Quantity = 9.6 bags

Cement Quantity in volume(m³)

Cement can find in volume (m³) just multiply the table value with volume the of structural member.

Cement Quantity = value of table × Volume

Cement Quantity = 0.22 × 1.5

Cement Quantity = 0.33 (m³)

To convert kilogram into bags simply divide the kilogram by 50 because 1 bag cement contains 50 kilograms.

Cement Quantity = 1980/50

Cement Quantity = 39.6 say 40 bags

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Quantity of Sand (m³)

Sand can find in volume (m³) just multiply the table value with volume the of structural member.

Quantity of Sand = value of table × Volume

Quantity of Sand = 0.44 × 1.5

Quantity of Sand = 0.66 (m³)

The quantity of sand can have calculated as the method for the estimation of the quantity of 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 “1” is the cement “2” is the sand while “4” is the coarse aggregate.

sum of the concrete ratio = 1+2+4

sum of the concrete ratio = 7

Quantity of Sand = (Sand Part / sum of ratio) × Dry Volume                              

Quantity of Sand = (2 / 7) × 9.625

Quantity of Sand = 2.75 m³

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Quantity of Coarse Aggregate

Coarse aggregate can find in volume (m³) just multiply the table value with volume the of structural member.

Quantity of Coarse Aggregate = value of table × Volume

Quantity of Coarse Aggregate = 0.88 × 1.5

Quantity of Coarse Aggregate = 1.32 (m³)

 

Water Cement Ratio

If water cement is not given by designer, we can assume the water cement ratio According to IS 10262 (2009). Here the value of water cement ratio is 0.50

Required Amount of Water = W/C Ratio X weight of Cement(kg)

Required Amount of Water = 0.50 X 480

Required Amount of Water = 240 liters

Note 

If you want to calculate the quantity of material and the dimension is given in foot or inches etc. simply convert these units (Unit Conversion) in meter & then calculate the materials in these methods which I have discuss in this article.

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