There are different layers of road . mostly 4 layer of road in which the first process of road is choose the way.
there are four layer.
1} NSL natural surface level .
2} W.B.M water bound macadam road.
3} prime court.
4} asphalt or toping.
N.S.L its the natural surface level of earth . the surveyor give us that point. surveyor had job to give point on which way road will go.
W.B.M {WATER BOUND MACADAM ROAD}
The road whose wearing course consists of clean crushed aggregates, mechanically interlocked by rolling and bound together with filler material and water laid on a well compacted base course is called water bound macadam (W.B.M) road .
3
in this process we used liquid form of bitchumin .
we change the bitchumin in liquid form and then the spray on w.b.m layer.
4}ASPHALT.
This is the final process of road .
Asphalt concrete pavement mixes are typically composed of 5% asphalt cement and 95% aggregates (stone, sand, and gravel). Due to its highly viscous nature, asphalt cement must be heated so it can be mixed with the aggregates at the asphalt mixing facility.
image source by google.