Cement, Sand, Aggregate and Steel Calculation for Rcc work

 

How to Calculate Quantity of Cement, Sand and Aggregate in RCC Slab 

1. Estimation of materials:

Material estimation include sand, cement, coarse aggregate and steel for a particular mix design. Let us consider a mix design of 1:1.5:3 for our estimation practice. The dry volume of total materials required is considered as 1.54 times the wet volume of concrete, due to voids present in sand and aggregates in dry stage. Therefore, for our calculation, we will consider the total volume of materials required as 1.54 m3 for 1 m3 of wet concrete.

Grade: M20

Mix Design: 1:1.5:3

(a) Bags of cement required:

Volume of cement required for 1m3 of Concrete -

     1 × 1.54               =    0.28 

  1 + 1.5 + 3

Volume of cement required for 1m3 of Concrete = 0.28 m3

volume of one bag of cement = 0.0347 m3

So, 

            

     0.28                   =       8 Bags/m3 

   0.0347

8 bags Cement required for Grade M20 Concrete in 1m3.

b) Volume of Sand required:

Volume of sand required 

     1.5 × 1.54                 =    0.42 

  1 + 1.5 + 3

Volume of Sandrequired for 1m3 of Concrete  =  0.42 m3.

c) Volume of Coarse Aggregate Required

Volume of Coarse Aggregate 

     3 × 1.54                 =    0.84

  1 + 1.5 + 3

Volume of Coarse Aggregate Required for 1m3 of Concrete = 0.84 m3

d) Estimation of Reinforced Steel:

Quantity of steel required depends on components of structure, i.e. slabs, beams, columns, foundations, roads etc. To estimate the steel required, there are two methods.

First method is, when we have the drawing available, we can calculate the total weight of steel required divided by total volume of concrete for different components. This will give us the weight of reinforcement steel per cubic meter of concrete.

Second method is assuming the percentage of reinforcement for different components. Following are the percentage of reinforcement steel generally required per different components. Its values can vary from structure to structure, and can be assumed from past experiences of similar structure.

For slabs = 1.0 % of concrete volume.

For Beam = 2 % concrete volume.

For column = 2.5 % of concrete volume.

For RCC Roads, 0.6% concrete volume.

Lets take example of RCC Column, where reinforcement required is 2.5% of concrete volume, weight of steel required will be:

e) Labour Requirement for 1m3 of RCC:

Labours required are presented in terms of days required by particular labour to complete its work for the given quantity of concrete. Following are the various labours required:

a) Mason:  As per Standard Schedule of Rates and Analysis of Rates, One mason is required for 0.37 days.

b) Labours:  One Unskilled labours required for 3.5 days.

c) Water carrier:  One water carrier required for 1.39 days.

d) Bar Bender:  Bar bender requirement depends on weight of reinforcement. Lets consider one bar bender required for 100 kg of steel as for 1 day.

e) Mixer Operator:  One mixer operator required for 0.0714 days.

f) Vibrator Operator:  One vibrator operator required for 0.0714 days.