The roads whose surface courses are made up of gravel materials of specified gradation and quality are called gravel road.
A. Collection of materials:
The sub grade soil shall be of good quality materials. It should not contain unwanted and deleterious material. The sub base material should not contain more than 6% clay particles and should be well graded. The base course material is mostly a crusher run materials having zero percentage clay content.
B. Selection of equipment:
Heavy equipment’s are used for the construction of gravel roads. The most widely used equipment’s in gravel road construction are loader, trippers, dumpers, excavators, grader, roller, etc.
C. Laying and compaction of martials:
The centerline and the road boundaries are marked on the ground by driving the wooden pegs. To follow the desired vertical profile of the road, reference pegs are also driven at a certain spacing which depends upon the estimated length of the road construction per day.
D. Pavement construction:
Crushed gravel aggregates are placed carefully in the trench so as to avoid segregation. Aggregate are spread with greater thickness at center and less towards the edges so as to obtain the desired camber. The layer is rolled using smooth wheeled rollers starting from the edges and proceeding towards the center. Some quantity of water may also be sprayed and rolling is done again so that the compaction is effective.
E. Opening to traffic:
The compacted earth surface is allowed to dry out for few days and then is opened to traffic.
