Question

In a mixture of 48kg concrete, the ratio
of cement and sand is 5 is to 3. Write the
equation between the cement and sand
Draw a graph and find the quantity
cement in the mixture.
please guys tell me the answer​

Answer 1

Answer:

Detailed analysis on M20 = 1:1.5:3 (Ratio)

As we know that during concreting when we place wet concrete , it gets harden after certain standard time( 30 mins IST & 10hrs FST), considering same it had be decided upon by Civil design Engineers to take a factor of safety ranging from 1.54 to 1.57 to counter that shrinkage.

i.e volume of dry Concrete = 1.54 to 1.57 times Volume of wet concrete.

Now calculations is as follows for 1cum(assumed) of Concrete work

ratio Sum = 1+1.5+3=5.5

Shrinkage or safety Factor =1.57 (you can take 1.54 also)

So Total volume of wet concrete required is :- 1.57cum

Volume of broken stone Require = (3/5.5) x 1.57 = 0.856 m3

Volume of sand Require = (1.5/5.5) x 1.57 = 0.471 m3

Volume of cement = (1/5.5) x 1.57 = 0.285 m3

= 0.285 x1440 = 411 kg

For 1m3 of M20 (1:1.5:3)

Broken stone = 0.856 m3

Sand = 0.472 m3

Cement = 8.22 bag.

Some important conclusion from above

8 bag of Cement is required for 1cum of concrete work in M20.

4.4 bag of cement is required for 1cum of concrete work in M10.

volume of dry concrete =1.54 times volume of wet concrete.

Thank You Folks!