### Dense Bituminous Macadam (DBM) or Bituminous Concrete (BC) layer Quantity / Compaction Factor value / Loose thickness calculation

**Dense Bituminous Macadam (DBM) or Bituminous Concrete (BC) quantity / Compaction Factor value for DBM or BC / Loose thickness of DBM or BC Layer**

In this article we shall discuss three important points about Dense Bituminous Macadam (DBM) or Bituminous Concrete (BC)

1- How can we calculate the required DBM/BC quantity?

2 - What is value of compaction factor for DBM/BC?

3- How much loose thickness should be taken to get proper compacted layer thickness ?

1- How can we calculate the required DBM/BC quantity?

Let us consider

Length of DBM/BC layer (L) = 1 Km = 1000 Met.

Breadth of DBM/BC Layer (B)= 5 Met.

Thickness of DBM/BC Layer (T) = 50 mm =0.050 Met.

Max. Dry Density (MDD) =2.441 Gram/ Cubic Centimeter = 2441KG/ Cubic metre

**Note**- The value of MDD is calculated by conducting suitable test .

Then

Volume of DBM/BC Layer = ( Length of DBM/BC layer X Width of DBM/BC layer X Thickness of DBM/BC Layer)

Volume of DBM/BC Layer = L X B X T Volume of DBM/BC Layer = 1000 X 5 X 0.050

Volume of DBM/BC Layer = 250 Cubic Metre

We Know That

Mass = Volume X Density

in this case -

Mass = Volume X MDD

Putting the value in the above Formula

Mass = 250 X 2441 Kg

Mass = 6,10,250 Kg

To convert above quantity in Tonn

We Know That

1 Tonn = 1000 Kg

Then

Mass =(610250/ 1000) Tonn

Mass = 610.250 Tonn

**Hence required DBM/BC**

**quantity is 610.25 Tonn.**

2 - What is value of compaction factor for DBM/BC?

Density of Blended aggregate = 1.60 gram/cc to 2.0 gram/cc

= 1600 - 2000 KG/ cubic metre

In this case

Let us consider

Density of Blended aggregate = 1.80 gram/cc = 1800 Kg / cubic metre

Value of Max. Dry Density (MDD) = 2.441 gram/cc = 2441 Kg/cubic metre

Compaction Factor = (Max.Dry Density/Density of Blended Aggregate )

=2.441/ 1.80

=1.3561= 1.36

**Hence compaction factor = 1.36**

3- How much loose thickness should be taken to get proper compacted layer thickness ?

Compaction factor = 1.36

Thickness of DBM/BC Layer = 50 mm

Hence

Loose thickness of DBM/BC Layer = ( Compacted layer thickness X Compaction Factor )

= 50 X 1.36

=68 mm

Hence

**Loose Thickness of DBM/BC Layer is 68 mm.**

**Thanks a lot**

**Mukesh Kumar**

**Gyan of engineering**

Thankyou .. Kudos for your blog. Keep going with your good work.

ReplyDeleteVery informative. Appreciable practical knowledge.

ReplyDeleteVery good information sir. If you have you tube chanel please tell me address it.

ReplyDeleteVery informative, sir I have a question while cross checking the quantity of survey with dumper trips, there are always arguments that loose quantity from plant needs to be same as compacted thickness. They say loose quantity before mixing only and after mixing only 10% air voids as per contractor arguments.

DeleteGood

ReplyDelete