Calculation of Quantity of Material For Concrete Mix Ratio

Calculation of Quantity of Material For Concrete Mix Ratio

Concrete is the mixture of cement, sand, aggregates and water. Cement concrete is the major building material in the construction industry. It can be easily moulded into durable structural members. Today in this article we will found out how to calculate the quantity of cement, sand, aggregate and water for 1 cum concrete.

For M-15

Grade of Concrete -  M-15 (1:2:4)                            (cement:sand:aggregate

Sum of ratio     =       (1+2+4) = 7

Wet volume of concrete = 1 cum.

To get dry volume, wet volume increased by 54%

Dry volume of concrete = 1 + 0.54

Dry volume of concrete =  1.54                         (Volume increased by 54%)

Why we take  54 %?

The reason is dry aggregate, sand and cement contain air voids. Dry aggregate contains 33 to 34% air voids, whereas sand contains 20% air voids and cement contains very fine particles hence it contains negligible are voids so we can ignore it. Now add the air voids of sand and aggregate that are 20% +34% = 54%  so this is the reason we have to add 54% for wet to dry volume of materials.

Quantity of Cement   =    Dry volume/sum of ratio × ratio of cement

=   1.54 / 7 × 1 = 0.22 cum       (where 1 is ratio of cement)

Quantity of cement in kg          = 1.54 / 7 × 1440              (Density of cement = 1440 kg/ m3)

=    316.8 kg

Quantity of cement in Bags       =  316.8 / 50 = 6.336    (weight of one bag cement = 50 kg

Quantity of cement in  cubic feet   =   Nos of bags × 1.226       (Volume of 1 bag cement = 1.226 cft)

Quantity of Sand in cum    =      1.54 / 7 × 2                       (where 2 is the ratio of sand )

=      0.44 cum

Quantity of Sand in  kg      =     0.44 × 1450                       (density of sand = 1450 to 1500 kg/m3)
=      638 kg

Quantity of Sand in cubic feet    =  1.54 / 7 × 2 × 35.314                        (1cum  =  35.314  cft )

=  15.53 cft

Alternative way  =  Nos of cement bags x Volume of one bag cement in cft × Ratio of sand

=       6.336 × 1.226 × 2
=       15.53 cft

Quantity of Aggregate in cum  =    1.54 / 7 × 4    (where 4 is the ratio of aggregate )

=    0.88 cum

Quantity of Aggregate in kg   =   0.88 × 1500        (Density of  Aggregate = 1450 to 1550 kg / cum )

=      1320 kg

Quantity of Aggregate in cubic feet  =   1.54 / 7 × 4 × 35.314

=    31.07 cft

Alternative way  =  Nos of cement bags × Volume of one bag cement in cft × Ratio of aggregate

=    6.336 × 1.226 × 4

=    31.07

Quantity of water

Let us consider water cement ratio  =  0.45

Water requirement for 1 bag cement =   0.45 x 0.0353          (Volume of 1 bag cement = 0.0353 cum)

=     0.0159 cum
1 cubic meter =  1000 liter

Water requirement for 1 bag cement =    0.0159 × 1000

=    15.9 liter

Water requirement for 6.336 bag cement =  6.336 × 15.9

=  100.74 litre
Conclusion

Cement      =    6.336 bags

Sand           =    0.44 cum

Aggregate  =    0.88 cum

Water         =   100.74 liter

Similarly, we can calculate the quantity of materials for different mix ratios.

Rate Analysis For 1 cum of  M15 Concrete

Material cost

Cement      =    6.336 bags @ 300/-  = 1900.8

Sand           =    0.44 cum @ 1000 per cum (crushed sand) = 440/-

Aggregate  =    0.88 cum @ 800 per cum = 880/-

Total Material cost is = 1900.8 + 440 + 880 = 3220.80

Labour Cost

1/2 mason and 2 labours for one day are required for carrying out 1 Cum concrete.

Mason @ 600 per day = 1/2 × 600 = 300

Labours @ 300 per day = 2 × 300 = 600

Total Amount of labour = 900/-

Subtotal = 3220.8 + 900 = 4120.8

Add 1.5% water charges  on subtotal amount = 4120.8 × 1.5% = 61.812

Add 15% for Overhead and  Profit on subtotal amount = 4120.8 × 15% = 618.12

So the rate per cum for M15 should be = 4120.8 + 61.812 + 618.12 = 4800.732 say 4800 cum

Approximate Rate For 1 cum of M15 Concrete is = 4800.00

Note

1. Shuttering component is not considered as the quantity of shuttering for the slab, beam, column and foundation shall be different.
2. The material rates considered in this rate analysis are exclusive of GST.
3. The material and labour rates may vary depending on the site condition & type of project.

Also, read - Concrete Mix Ratio For Various Grade Of Concrete - Concrete Mix Design