The earthen road is the cheapest type of road. The pavement structure is constructed totally from the soil available at the site. It is advantageous if we have to construct the road at the limited fund and this road may further needed to be improved in the future for an increase in traffic volume. This type of roads is generally found in village areas. It is a type of Low-Cost Road.
1.11: Types of Earth Road
a)Ordinary Earth roads
The earth road whose foundation and the wearing surface consists of one or two compacted layers of natural soil available along its alignment is called an ordinary earth road. Ordinary Earth road is the lowest form of pavement surface used so far and is considered as the first stage in the development of road pavement construction. The surface of such a type of road is generally dusty and ruts are quickly formed. These types of road require frequent maintenance to make them serviceable.
b)Stabilized Earth roads
The roads having its foundation and wearing surface consisting of one or two compacted layer of stabilized soil is called Stabilized Earth road. Stabilizes Earth road can carry greater traffic, load and provide better service as compared to ordinary earth roads.
1.12: Materials required
The material which is required for Earthen road is well-graded soil with a liquid limit of less than 35% and plasticity index of 4-10%.
1.13: Tools and equipment
1.14: Construction Procedure of Earthen Road
The construction procedure of Earthen material are listed below:
1) Soil Survey
Soil Survey is carried out and suitable barrow peg is located within the economic haulage distance.
The centerline of road and road edges are marked with the help of wooden peg.
3)Preparation of sub-grades
– It is required to clear road site from grasses and vegetal covers.
b)Excavation or filling up to the desired grade.
c)Shaping the sub-grade.
d)Compacting the sub-grade.
The borrowed soil is dump on the prepared sub-grade and is spread so that desired cross slope (i.e camber) and other features are provided and final compaction is done at OMC to get the required grade of compaction.
5)Opening to traffic
The compacted earth roads are allowed to dry for a few days before opening to traffic.
1.2: Advantages of earthen road
Some advantages of earthen roads are listed below:
1) It is the cheapest type of road and can be constructed in a very low budget.
2) Earth materials are easily available.
3)Local people and materials are utilized during the construction.
1.3 Disadvantages of earthen road
1)Greater maintenance cost as compared to the other types of roads.
2)Earthen roads are closed for vehicle movement during the period of monsoon.