How to determine the quantity of materials & labors of the Macadam road

In this exclusive civil engineering tutorial, one will learn how to determine the quantity of materials for the water bound macadam road (WBM) as well as the cost of developing this type of road.

Macadam road stands for a type of road in which single-sized crushed stone layers with small angular stones are arranged in shallow lifts and condensed comprehensively.

The calculation is done for determining the construction cost of the road on the basis of the following data :-

The length of the road = 1 Kilometer
The width of the road = 3.5 meters
Besides, the road contains 20 cm base with 10 to 20 cm size stone boulders and 10 cm thick road metal of 1.5 to 3 cm size crushed stone.
Arrangement of sub grade and dressing

No = 1
Length = 1000 meter (as 1 km = 1000 m)
Breadth = 3.80 m (3.5 +0.15 + 0.15)
Depth = 0 (as subgrade is a surface and there is no depth or thickness)
So, the quantity of subgrade = Number x Length x Breadth = 1 x 1000 x 3.80 = 3800 m²

Calculation of the materials of sub base

No = 1
Length = 1000
Breadth = 3.80

Depth = 20 cm (but it can’t be taken as it is consolidated; it is required to add half depth to compacted depth to recover the loss of depth as well as get the depth or height of sub base).

So, or depth or height = 0.20 + 0.10 = 0.30 m (20 cm or 0.20 m and 20/2 = 10 cm or 0.10 m).

Also Read: Building and Road Estimating Sheet

So, the quantity of sub-base = Number x Length x Breadth x Height = 1 x 1000 x 3.80 x 0.30 = 1140 m³.
The quantity of labor for spreading and compaction of sub-base will be same i.e. 1140 m³.

Calculation of base layer materials

No = 1
Length = 1000
Breadth = 3.50
Depth or height = ½ of 0.30 = 0.15 (to recover loss of depth, half depth is added)

So, the quantity of base materials = Number x Length x Breadth x Height = 1 x 1000 x 3.50 x 0.15 = 525 m³

Labor for spreading and compaction of base will be same i.e. 525 m³

The abstract cost of sub-grade, sub-base and base will be calculated as follow :-

Preparation, consolidation and dressing of sub-grade

Quantity = 3800
Unit = m²
Rate = 20 rupees
Amount = 20 x 3800

Rate is taken from Market Rate System (MRS) of your own country.

The same method can be applied to find out the cost of materials and labor for sub-base and base.

To get more clear ideas, go through the following video presentation.