## Method-1: DLBD method to determine material requirement for 1 Cum concrete

The DLBD (Dry Loose Bulk Densities) method is an accurate method to calculate cement, sand and aggregate for a given nominal mix concrete. This gives accurate results as it takes into account the Dry Loose Bulk Densities of materials like Sand and Aggregate which varies based on the local source of the material

For calculation, We consider a nominal concrete mix proportion of 1:2:4 (~M20).

### Step-1: Calculate Weights of Materials Required

To arrive at different quantities of concrete ingredients, the Dry loose bulk density of materials plays important role as they are batched loosely.

Considering Dry loose bulk density of following concrete ingredients as

Cement = 1440 kg/cum ; Fine Aggregate = 1600 kg/cum ; Coarse Aggregate = 1450 kg/cum ; Water = 1000 kg/cum

The dry loose density varies for

Considering a concrete mix proportion (by volume) of 1:2:4

i.e., Cement: Fine aggregate (Sand) : Coarse Aggregate is in the ratio of 1:2:4 by volume.

Cement required = 01 bag = 50 kg ~ 36 liters or 0.036 cum

Fine Aggregate required = 2*0.036 ~ 0.07 cum = 0.072*1600 = 115 kg

Coarse Aggregate required = 4*0.036 ~ 0.14 cum =0.144*1450 = 209 kg

Considering water – cement ratio (w/c) of 0.55 , water = 0.55*50 kgs = 27.5 kg

### Step-2: Calculate Material Requirement for Producing 1 Cum Concrete

The volume proportion in weight turns out to be

Cement : Sand : Aggregate (in Kgs) is 50 kgs : 115 kgs : 209 kgs (by weight)

Water required for the mixture = 27.5 kgs

Total weight of concrete ingredients = 50+115+209+27.5 = 401.5 say 400 kg

Density of concrete = 2400 kg/cum

So, 1 bag of cement produces = 400/2400 = 0.167 cum

No. of bags required for 01 cum of concrete = 1/0.167 = 5.98 bags ~ 6 bags

From above, if the concrete mix is 1:2:4 , to get a cubic meter of concrete we require

1.Cement = 6 bags = 300 kgs.

2.Fine Aggregate = 115/0.167 = 689 kg

3.Coarse Aggregate = 209/0.167 = 1252 kg.

4.Water = 300/0.55 = 165 kg.

Like wise other concrete mix with varying proportions and materials with different physical properties ,the individual quantities of different ingredients can be easily arrived.