## HOW TO CALCULATIONS OF QUANTITIES OF CEMENT SAND AND AGGERGARE FROM 1 m3 (ONE CUM) OF CONCRETE (NOMINAL MIX DESIGN)

·
Nominal
mixed concrete may be used for concrete of grade M 20 or lower.

·
To calculate
the individual quantity of cement, sand and aggregate and water in 1 cum of
concrete we assuming the nominal mix design concrete of grade M20.

Ã˜
As per IS
456:2000 in M20 grade of concrete the proportion of Cement, Sand and Aggregate
is,

**Cement: Sand: Aggregate = 1:1.5:3**

Ã˜
Adding all
the volume to obtain the total volume i.e.

**Cement+Sand+Aggregate = 1+1.5+3 = 5.5**

Ã˜

**I am assuming 1.54 as factor of safety.**
(As we know that, voids are there
in dry mix of concrete. Water is added in dry material to make it wet concrete
and then placed in shuttering particles slides to readjust in pores and voids
reducing the volume of it. In case of stone aggregate the void ratio
compressibility is 32 to 33% where as that of sand is 20% and assuming that the
cement particles being very fine get adjusted in compressed voids total volume
of dry material (having 0.33+0.20 = 0.53) has nearly 52 to 54% more volume than
when in wet state.

So the volume of dry material for
concrete is achieved by multiplying wet concrete by 1.54. Based on same reason
if we want to get volume of dry material for mortar wet volume should be
multiplied by 1.20. However some engineers add 5% to 10% to multiplicative
figure of 1.54 or 1.20 to account for wastage and poor workmanship.)

Ã˜
So for 1 m

^{3}of M20 grade wet concrete, the total dry Volume of concrete required is 1.54 m^{3}.
·

__Calculation for Volume of Cement in 1cum of Concrete(M20)__**:-**
For 1m3 of Concrete = 403.2Kgs of Cement
is required.

No. of Cement Bags required for 1m3 of
Concrete = 403.2/50 = 8.06 ~ 8 bags. (1 Bag of cement = 50 kg)

**Hence, cement required for 1cum of concrete = 8 bags.**

·

**:-**__Calculation for Volume of Sand (Fine Aggregate) in 1cum of Concrete(M20)__
Sand usually consists of moisture content. It
increases the volume of sand (bulking of sand).

For accurate calculation use dry sand or
include the effect of bulking.

**Hence, sand required for 1 cum of concrete = 672 kg.**

·

__Calculation for Volume of Coarse Aggregate in 1cum of Concrete (M20)__**:-**
Density of aggregate may go higher if void
spaces decreases. As size of 5 mm aggregate has more density when compared with
20mm aggregate.

**Hence, 20mm aggregate required for 1 cum of Concrete = 1310.4 Kg**

·

__Calculation for Water Requirement for 1 cum of Concrete( M20)__**:-**
For the
preparation of concrete required qty of water, is added to the dry mix of
concrete, depending upon the workability and climatic factors. Generally, we
maintain 0.35 – 0.50 of water cement ratio. Always remember above value may
change according to the moisture content present in sand and aggregate.

Cement
required for 1 cum of M20 grade concrete

**= 403.20 kg**
Assuming
Water Cement Ratio

**= 0.50**(50% of cement)
Water
required for 1cum of Concrete =

**403.20 x 0.50****= 201.60 kg**

**= 201.60 ltr.**

·
From the above calculation we get the
quantities of material for M20 grade of concrete as follows –

Cement =
403.20 kg

Sand = 672
kg

Aggregate
= 1310.40 kg

Water =
201.60 liter

·
Similarly we can also calculate the
requirement of materials (Cement, Sand, Aggregate & Water) for concrete
grade like – M5, M7.5, M10, M15 etc.

Cl me we discuss on this 9113238347

ReplyDelete