Types of Pavement
Based on design consideration Pavements are classified into two types of pavement.
- Flexible Pavement
- Rigid Pavement
1. Flexible Pavement
Flexible pavements are those types of pavement which are surfaced with asphalt or bituminous materials.
These pavements are called flexible because the pavement structure bends due to traffic loads, the design consideration is taken based on load distribution characteristics of the component layer.
These are usually made up on number of layers such as Subbase,base course and surface course. Surface course or top layer must be strongest as it bares highest compressive test.
While the bottom layers is not in direct contact with traffic loads so there is less wear and tear, Hence low cost materials can be used in bottom layer.
The top layer of flexible pavement transmit the vertical or compressive stresses to the bottom or lower layers through grain transfer by contact points of granular structure.
Vertical compressive stress is maximum at the pavement surface or top layer which is directly under the wheel load and is equal to contact pressure under the wheels. Due to the ability to distribute the stress to large area in the shape of truncated cone the stresses get decreased in the lower layer.
2. Rigid Pavement
Rigid pavements are those types of pavement which are surfaced with cement concrete either with plain,reinforced or prestressed Concrete.
Rigid pavements are designed to provide strong cement concrete slab with sufficient strength to carry the traffic loads.
The rigid pavement has rigidity and high modulus of elasticity to distribute the load over a relatively wide area of soil.
Rigid pavements are designed based on elastic theory, Any variation in the subgrade strength has little impact on the structural capacity of the pavement.
Advantages of Rigid Pavement
- Rigid pavements are more durable(30+years) when compared to Flexible pavement(5-10 years)
- Due to more durability the maintenance and repair cost are less but initial cost are quite high.
- These types of pavement has high efficiency
Also Read – What are Spillways? Types of Spillways
Difference between Flexible and Rigid pavement
| Sl.No | Flexible pavement | Rigid pavement |
|---|---|---|
| 1 | The deformation of subgrade reflects the subsequent layers | The deformation of subgrade does not reflects the subsequent layers,instead bridge over the failures. |
| 2 | Flexible pavement has low flexural strength | Rigid pavement has high flexural strength |
| 3 | Surface must be rolled | No rolling of Surface |
| 4 | Road strength mainly depends on strength of the Subgrade | Road strength does not depend on strength of the Subgrade |
| 5 | Flexible pavements can self heal any deformations. | Rigid pavements cannot self heal any deformations. |
| 6 | Temperature variation does not produce any stress in flexible pavement. | Temperature variation produce any heavy stress in rigid pavement. |
| 7 | Initial cost is low but maintenance and repair cost is high | Initial cost is high but maintenance and repair cost is low. |
Also Read – Difference Between Backhoe vs Excavator