Earthen road is a type of road, whose whole pavement section is constructed with the locally available earth material.
A. Collection of material:
Suitable borrow pits are located by doing the survey of the adjacent land which are easy to reach and at economical haulage (transportation) distance. The various organic materials like trees, shrubs and grass roots are removed before the excavation of the earth.
B. Location of centerline:
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.
C. Preparation of sub grade:
Following steps are necessary for the preparation of the sub-grade
The site clearance may be done manually using appliances like spade, pick and hand shovel or using the mechanical equipment like Bulldozer and scraper etc. Excavation and construction of fills may also be done manually or using the excavation, hauling (ढुवानी) and compaction equipment. Dozers are considered very useful for haulage of short distances. If the compaction is done manually it will not be sufficient and proper, it should be left to get consolidated under atmospheric conditions. The subgrade should be compacted to the desired grade, camber and longitudinal profile.
D. Pavement construction:
The soil is dumped on the prepared sub-grade and pulverized (to reduce). The soil may be a mixture of more than one soil to get the desired properties. The moisture content is checked and if extra moisture is needed, is added to bring it to optimum moisture content. The soil is mixed, spread and rolled in layers such that the compaction thickness of each layer does not exceed 10 cm. The type of roller for compaction is decided based on soil type, desired amount of compaction and availability of equipment. At Least 95% of dry density of is considered desirable. The camber of the finished surface is checked and corrected when necessary.
E. Opening to traffic:
The compacted earth surface is allowed to dry out for few days and then is opened to traffic.
