Volumetric conversion of SCC Mix Design

To convert a concrete mix design which is generally given in terms of cubic meter into practical application when the mixing quantity required is small such as 1 bag of cement the weight of ingredients is converted into volume. These conversions are generally termed as volumetric conversions of concrete mix design.

For example, let us consider the following mix design at SSD condition for M25 SCC concrete.

Cement: 330.42 Kg

FlyAsh: 116.58 Kg

Fine Aggregate- River sand: 922.35 Kg 

Coarse Aggregate- 10 mm: 542.31 Kg

Coarse Aggregate- 20 mm: 450.21 Kg

Water: 158.00 Kg

Admixture: 3.13 Kg

now, we need to get the volumes of ingredients as per 1 bag of cement,

Weight of cement per Bag : 50.00 Kg

Ratio between total cement quantity & per bag: 330.42/50.00 = 6.61

Therefore reduced quantity as per 1 bag of cement comes to -

Fly Ash: 116.58 / 6.61 = 17.64 Kg

Fine Aggregate- River sand: 922.35 / 6.61 = 139.57 Kg 

Coarse Aggregate- 10 mm: 542.31 / 6.61 = 82.06 Kg

Coarse Aggregate- 20 mm: 450.21 / 6.61 = 68.13 Kg

Water: 158.00  / 6.61 = 23.91 Kg

Admixture: 3.13 / 6.61 =  0.47 Kg

With these values we can now convert it into volumes by simply multiplying the weight of ingredient with specific gravity of that particular ingredient again multiply by 1000 and it will give the volume of that ingredient in cubic meter.

Fly Ash: 17.64 x 2.23 x 1000 = 0.039 Cubic Meter

Fine Aggregate- River sand: 139.57 x 2.76 x 1000 =  0.385 Cubic Meter 

Coarse Aggregate- 10 mm: 82.06  x 2.84 x 1000 = 0.233 Cubic Meter

Coarse Aggregate- 20 mm: 68.13 x 2.87 x 1000 =  0.196 Cubic Meter

Water: 23.91 x 1.00 x 1000 =  0.024 Cubic Meter

Admixture: 0.47 x 1.10 x 1000 =  0.001 Cubic Meter

After getting these data, any combination of sizes may be assumed as long as it maintains the actual volume of that particular ingredients. Generally, when casting is carried out manually (I.e. without a batching plant) these volumetric conversions is required, so as the mix design can be maintained without a strict supervision of any engineer. These data are used to make forma or boxes to keep the volume of ingredients easy to maintain.