Quantity of material required for the production of required quantity of concrete of given mix proportions can be calculated by absolute volume method.

Volume method is based on the principle that the volume of fully compacted concrete is equal to the absolute volume of all the materials of concrete, that is cement, fine aggregate (sand) , coarse aggregates and water.

Volume method is based on the principle that the volume of fully compacted concrete is equal to the absolute volume of all the materials of concrete, that is cement, fine aggregate (sand) , coarse aggregates and water.

Vc: Absolute volume of fully compacted fresh concrete

W: Mass of water

C: Mass of cement

Fa: Mass of fine aggregates

Ca: Mass of coarse aggregates

Sc, Sfa and Sca are the specific gravities of cement, fine aggregates and coarse aggregates respectively.

*AIR CONTENT IS IGNORED IN CALCULATION

This method of calculation for quantity of material for concrete takes into account the mix proportions from design mix or nominal mixes for structural strength and durability requirement.

Consider concrete with mix proportion of 1:1.5:3 where, 1 is part of cement, 1.5 is part of fine aggregates and 3 is part of coarse aggregates of maximum size of 20 mm. The water cement ratio required for mixing of concrete is taken as 0.40

Cement = 1500 kg/m3

Sand = 1700 kg/m3

Coarse aggregates = 1650 kg/m3

Cement = 3.15

Sand = 2.6

Coarse aggregates = 2.6.

The percentage of entrained air assumed is 2%.

The mix proportion of 1:1.5:3 by dry volume of materials can be expressed in terms of masses as:

Cement = 1 x 1500 = 1500

Sand = 1.5 x 1700 = 2550

Coarse aggregate = 3 x 1650 = 4950.

RATIO OF MASSES WITH RESPECT TO CEMENT:

W: Mass of water

C: Mass of cement

Fa: Mass of fine aggregates

Ca: Mass of coarse aggregates

Sc, Sfa and Sca are the specific gravities of cement, fine aggregates and coarse aggregates respectively.

*AIR CONTENT IS IGNORED IN CALCULATION

This method of calculation for quantity of material for concrete takes into account the mix proportions from design mix or nominal mixes for structural strength and durability requirement.

__FOR EXAMPLE:__Consider concrete with mix proportion of 1:1.5:3 where, 1 is part of cement, 1.5 is part of fine aggregates and 3 is part of coarse aggregates of maximum size of 20 mm. The water cement ratio required for mixing of concrete is taken as 0.40

**Assuming bulk densities of materials as follows:**Cement = 1500 kg/m3

Sand = 1700 kg/m3

Coarse aggregates = 1650 kg/m3

**Specific gravities of concrete materials are as follows:**Cement = 3.15

Sand = 2.6

Coarse aggregates = 2.6.

The percentage of entrained air assumed is 2%.

The mix proportion of 1:1.5:3 by dry volume of materials can be expressed in terms of masses as:

Cement = 1 x 1500 = 1500

Sand = 1.5 x 1700 = 2550

Coarse aggregate = 3 x 1650 = 4950.

RATIO OF MASSES WITH RESPECT TO CEMENT:

Water cement ratio= 0.40

ABSOLUTE VOLUME OF CONCRETE FOR 50 KG (1 BAG) OF CEMENT:

ABSOLUTE VOLUME OF CONCRETE FOR 50 KG (1 BAG) OF CEMENT:

THEREFORE FROM ONE BAG OF CEMENT (50 KG) 0.13202 m3 OF CONCRETE CAN BE MADE.

FOR 1m3 OF CONCRETE 2% AIR IS ENTRAINED.

ACTUAL VOLUME OF CONCRETE= 1-0.02= 0.98m3

QUANTITY OF CEMENT REQUIRED FOR 1m3 OF CONCRETE= 0.98/0.13202=7.42 BAGS OF CEMENT

=7.42* 50 Kg

=

Weight of fine aggregate (sand)= 1.5* 371=

Weight of coarse aggregate =3* 371=

FOR 1m3 OF CONCRETE 2% AIR IS ENTRAINED.

ACTUAL VOLUME OF CONCRETE= 1-0.02= 0.98m3

QUANTITY OF CEMENT REQUIRED FOR 1m3 OF CONCRETE= 0.98/0.13202=7.42 BAGS OF CEMENT

=7.42* 50 Kg

=

__371 Kg__

Weight of fine aggregate (sand)= 1.5* 371=

**556.5 Kg**Weight of coarse aggregate =3* 371=

__1113 Kg__**RELATED ARTICLES:**