calculate of Sand, cement and aggregate of Design mix M20 ,M25 etc

How we calculate of Sand, cement and aggregate Of M10 , M15 , M20 and M25 etc

Example

M20  = 1:1.5:3 (Ratio)

wet concrete volume to dry concrete volume which can get with multiplying from 1.54 to 1.57 with the wet volume of concrete

Example : Dry volume of concrete = 1.54 to 1.57 times volume of wet concrete.

Assume that we will find the materials calculation for 1 cum of concrete work.

So for M20 Grade of Concrete we have ratio = 1+1.5+3

Sum of ratio = 1+1.5+3

So total volume of is 1 cum.

Now change it the 1 cum volume of concrete to dry volume.

so ,  wet volume of concrete x 1.53

Dry volume of concrete = 1 x 1.57  = 1.57 cu.m

Now find the volume of cement =  Volume of cement = (1/5.5) x 1.57 = 0.285 m3

Volume of cement in kg = 0.285 x 1440 = 411 kg        where 1440 kg / cu.m

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

Volume of Crush = (3/5.5) x 1.57 = 0.856 m3

Some useful Information for the above calculation in detail

Volume of Cement = 0.285 cu.m   Or      Cement = 8.22 bag   Because one bag of Cement is equal to 50 kg.

Volume of Sand = 0.471 cu.m

Volume of Crush  =0.856 cu.m

we know that Concrete proportion for M20 is (1:1.5:3)

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.

similarly for other grade of concrete we can calculate.

How to find the Good Quality of Cement at site

1.Date of Packing :

When we use any type of cement for construction works so first of all we have to check the manufacturing date of cement , Because the cement should be used before 90 days from the date of packing .

2: Rubbing Test : 

We should get the punch of cement with finger and the cement should be rubbing between the finger, so that time the cement should be feel smooth.

3: Float Test : 

For float test we have to put some amount of cement in the glass or other box, so the cement should be float for sometime before its sitting .

4: Temperature Test

Temperature test we can find very easily , first we pick some cement from the cement bag . so that cement should give us cool feeling than it will be the good cement.

Simply insert your hand into the cement bag, it should give cool feeling if its quality is good. Otherwise, you may feel warm because of hydration reaction.

5: Strength Test

Prepare a cement block of 25 mm x 25 mm and 200 mm in length. Now submerge it in water for 7 days. Now place it on supports 15 cm apart and load it with 34 kg weight. Block made from good cement will not show any signs of failure.

6: Check for Lump Test

The lumps should be not present in the cement . and the lumps can come in the cement due to absorption of climate.

7: Color of Cement

The cement color should be uniform gray color with  with greenish shad.