Well, this is the fundamentals things of Building Estimation
that every civil Engineer should go through it. Concrete comprises cement, fine
aggregates, coarse aggregates and water in mix proportion.you can also Learn how to calculate the quantities of ingredients in slab
In this article I have explained the quick method to
calculate the quantities of all ingredients.
Let us calculate the quantities
Note: for Concrete
work: Dry volume =wet volume x 1.54
For mortar
work : Dry Volume = wet volume x 1.33
Consider,
Grade of concrete (M15) =1:2:4
Where 1= part of cement, 2 = part of sand, 4 = parts of
aggregates
Total ratio = 1+2+4 =7
Volume of concrete
=1m3 (wet volume)
Dry volume = 1x 1.54 m3 = 1.54 m3
Let us know by the help of above information I will
calculate the quantities of cement, sand and aggregates.
1.Cement Quantity
Quantity of cement in m3 = Dry
Volume x (part of cement / total ratio)
=
1.54 x (1/7) =0. 22 m3
Quantities of cement in kg = 1.54 x (1/7)
x1440 = 316.8 kg (Density of cement =1440 kg/ m3)
Quantities of cement in bags = (316.8/ 50)
=6.336 bags (1 bags = 50 kg)
2..Sand /Fine Aggregates Quantity
Quantity of sand in m3 =1.54 x
(2/7) =0.44 m3
Quantity of sand in kg =( 0.44 x 1450) =638 kg
(Density of sand =1450-1500)
Quantity of sand in ft3 = 0.44 x
35.3147 = 15.54 ft3 (1 m3 = 35.3147 ft3)
3.Coarse Aggregates Quantity
Quantity of aggregates in m3
=1.54 x (4/7) =0.88 m3
Quantity of aggregates in kg = 0.88x1500
=1320 kg (Density of aggregates =1450 -1550)
Quantity of aggregates in ft3
=0.88 x 35.3147 = 31.076 ft3
4. Water Quantity
Quantity of water in liter depends upon the
water cement ration and quantity of cement.
In the above examples I have calculated
Weight of cement in m3 = 0.22 m3
Consider water cement ration = 0.45
Amount of water required in 1 m3
concrete work = Water cement ratio x cement weight
Now, Water = 0.45 x0.220 =0.0999 m3
Amount of water required in liter= 0.0999 x
1000 = 99.9 liters.
Therefore,
For 1 m3 concrete work, 6.336 bags, 15.54 ft3
sand, 31.076 ft3
And 99.9 liters required having 1:2:4
proportions.
Let us take the example slab having length
of 5 m, width of 3 m and thickness of 150 mm.
Length of slab = 5 m
Width of slab = 3 m
Thickness of slab =0.15 m
And, M15 =1:2:4 where 1 parts cement, 2
part sand, 4 part aggregates
Volume of slab = length x width x thickness
= 5 x 3 x 0.15
= 2.25 m3
We got Wet Volume = 2.25 m3
Therefore, Dry Volume =2.25 x1.54 = 3.465 m3
Quantities calculation of Slab
1. Cement Calculation
Volume of cement in m3 = 3.465 x (1/7)=0.495 m3
Volume of cement in bags = (0.495 x 1440) /50 = 14.25 bags
2. Sand calculation
Volume of sand in m3
= 3.465 x(2/7) = 0.99 m3
3. Aggregate calculation
Volume of aggregate in m3 = 3.465 x(4/7) =1.98 m3
4. Water Quantity
Quantity of water in m3 = w/c x volume of cement in m3
= 0.45 x 0.495 = 0.22275 m3
Quantity of water in liter = 0.22275 x 1000 =222.75 liters ( 1 m3
= 1000 liters)
Therefore for 2.25 m3 of slab,
14.25 bags, 0.99 m3 sand, 1.98 m3 coarse aggregates and
222.75 liters are required.
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