Material estimation for M25 grade concrete. / Estimation of cement, sand, & aggregates in M25 ( 1:1:2 mix ratio) concrete.

 Let us consider 1 CUM of M25 grade concrete for the calculation purpose.

Here, 

Cement:sand: aggregates = 1:1:2 (a:b:c)

M25 grade means 👉  1:1:2 ratio.

Wet volume of  M25 grade concrete = 1 CUM.

Now, the dry volume of concrete 

                 = 1.54 × wet volume of concrete.

                = [1.54 × 1 cum] = 1.54 cum.

              

1. Volume of  cement required

   = [{its ratio  ÷ (total ratio)} × dry volume of concrete.]

    =[{ a ÷ (a + b + c)} × dry volume of concrete.]

   = [{1÷ ( 1 + 1 +2 )} × 1.54]

   = [{ 1 ÷ 4 } × 1.54]

   = [0.25 × 1.54]

   =  0.385 cum.

As you know, 1 bag of cement = 0.03472 cum.

So, the number of cement bags required

       = [0.385 cum. ÷ 0.03472 cum.]

       = 11.089 bags  

Weight of cement 

= [11.089 bags × 50 kgs.]

(1 bag of cement = 50 kgs.)

= 554.44 kgs.

2. Volume of sand required

     = [{its ratio  ÷ (total ratio)} × dry volume of concrete.]

    =[{ b ÷ (a + b + c)} × dry volume of concrete.]

   = [{1÷ ( 1 + 1 +2 )} × 1.54]

   = [{1 ÷ 4 } × 1.54]

   = [0.25 × 1.54]

   =  0.385 cum.

  =  13.60 cu ft.

3. Volume of aggregates required

     = [{its ratio  ÷ (total ratio)} × dry volume of concrete.]

    =[{ c ÷ (a + b + c)} × dry volume of concrete.]

   = [{2÷ ( 1 + 1 +2 )} × 1.54]

   = [{ 2 ÷ 4 } × 1.54]

   = [0.5 × 1.54]

   =  0.77cum.

   = 27.19 cu ft.

4. Volume of water required.

  Let us consider the w/c ratio for M25 grade concrete as 0.4.

i.e. wt. of cement / wt. of water = 0.4

 So, the weight. of water 

       = 0.4 × wt. of cement 

       =0.4 × 554.44 kgs

      = 221.776 kgs

     = 222 liters 

      ( 1kg= 1 liter)

Note: This w/c ratio holds good if you use plasticizers. Practically for good workability, the water we add for the concrete is 250 to 270 liters.

Alternate method:

1. Volume of cement ( from above) = 0.385 cum.

2. Volume of sand     

         = [volume of cement × b]

         =   [0.385 cum × 1]

         = 0.385 cum.

3.  Volume of aggregates

      = [volume of cement × c]

      = [ 0.385cum × 2]

      = 0.77 cum.

Now, let us put these material quantities in a table format for easy reference.

Materials in 1CUM of M25 grade concrete.
Sl. No.	Item	Unit	In cum.	In cu ft.
1.	Cement	bags	11.089 bags	-
2.	Sand	-	0.385	13.60
3.	Aggregates	-	0.77	27.19
4.	Water	litres	222	-

 

Next part 👇

What will be the cost of M25 grade concrete ?/How to calculate the cost of concrete having a 1:1:2 mix ratio?

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