HOW TO CALCULATE CEMENT, SAND AND AGGREGATE FROM PCC SLAB.

Lean Concrete: Lean concrete is a type of concrete which is not so strong in compressive strength. It is mainly used to provide a hard and leveled surface. It also protects the foundation concrete from coming directly in contact with the soil.

Generally we M_7.5 or M₁₀ as a Lean concrete or PCC Slab.

Here, let us suppose M7.5 as the grade of PCC Slab.

Then the ratio will be – 1:4:8 i.e. (1 cement, 4 sand and 8 Aggregate)

Let us assume a rectangular PCC Slab

Let the Length be – 8 m

and Width be – 6 m

And the thickness of the Slab be – 10cm

Now, Let us find the Cement, sand and the

Aggregate used in the Slab.

As we know that,

the volume of the Slab = L*b*h ( i.e. Length, width and thickness)

Vol. of slab = 8*6*0.1 m3

Vol. of Slab = 4.8 m3, ( This is wet vol., For Dry vol. multiply by 1.54)

Now, Dry Volume of PCC Slab = 4.8*1.54 = 7.392 m3 or 7.4 m3

Hence, Dry Volume of PCC Slab = 7.4 m3, (RATIO of Concrete = 1: 4: 8)

= cement/(cement+sand+aggregate)* 7.4 m3

= 1/(1+4+8)*7.4 m3

= 1/13*7.4 m3, = 0.56 m3 { Since 1m3 cement = 1440 kg}

So, 0.56 m3 cement= 0.56*1440

= 806.4kg

Now , No. of cement bags required = 806.4/50 = 16.12 bags

OR , 16 Bags

= sand/(cement+sand+aggregate)* 7.4 m3

= 4/13*7.4 m3, = 2.276 m3 or 2.28 m3 ( Now, 1m3 Sand = 1600kg)

So, 2.28*1600kg = 3648kg ( Also, Wt.of 1 CFT Sand = 43.3kg)

Therefore, Vol.of Sand = 3648/43.3 cft

=84.24 cft

= Aggregate/(cement+sand+aggregate)* 7.4 m3

= 8/13*7.4 m3, = 4.55 m3, (Also,1m3 Aggregate = 1800kg)

So, 4.55*1800kg = 8190kg, (Wt. of 1CFT Aggregate = 68.15kg)

Therefore, Vol of aggregate = 8190/68.15 cft

= 120.17 cft