Function of Soil as a Road Material
The soil as Roads subgrade has the following function:
1. Soil is an essential component in the road construction which is used as subgrade material.
2. It acts as an integral part of the road pavement.
3. It ensures the stability and durability of the road under adverse conditions.
4. It facilitates proper drainage for rainwater percolating through the road pavement.
5. It helps to overcome some critical defects on roads like waves, corrugation, rutting in blacktop pavement and cracking of cement concrete pavement by providing proper subgrade stability and durability.
Properties of Soil as a Road Material
The properties of soil as a road material are as follows:
1. The soil subgrade should remain stable in adverse condition.
2. It should have permanent strength.
3. It should be incompressible.
4. It should have proper drainage properties to evade excessive retention of moisture.
5. It should be easily compatible which ensures higher dry density(dry density of soil) and strength under particular type and amount of compaction.
6. It should have minimum variation in volume under adverse conditions of weather and groundwater. The minimum change in volume will ensure minimum variation in differential strength and differential expansion.
Method of Providing Superelevation