Flexible Pavement and Rigid Pavement - the major differences between them

The pavement on the road is the layered structure located directly above the subgrade as well as under the wearing surface of the road, which is responsible for transmitting the loads from the vehicles to the sub grade and underlying soil.

As a result of design considerations, there are two types of pavements, namely flexible pavements and rigid pavements. This article is going to cover a brief discussion of the differences between flexible pavement and rigid pavement in a nutshell.

What do you mean by Flexible Pavement?

There are very low flexural strengths associated with flexible pavements, and they are flexible in their structural action under the pressure applied by vehicles. Wheel load stresses are transferred from the higher layer of the pavement to the lower layer of the pavement when this pavement is constructed. There is an even distribution of the wheel load over a wider area, as well as a reduction in the stress as the depth increases.

Asphalt is one of the most common bituminous materials that is used to construct flexible pavements. The top layer is supposed to sustain maximum compressive stress whereas the lower layers will experience a lesser magnitude of stress.

There are three components to flexible pavements: a surface course made of bituminous material and underlying base and sub base courses made of granular material. It is more common for the bituminous material to be asphalt, because of its viscous nature, it is able to undergo considerable plastic deformation. There are some asphalt surfaces built directly on the sub grade, whereas some asphalt surfaces built on a gravel base are also called 'full depth asphalt surfaces.

What are the varieties of Flexible Pavement?

There are generally three varieties of Flexible Pavement, they are as follows:

1. Full depth asphalt pavement
2. Contained rock asphalt mat (CRAM)
3. Conventional layered flexible pavement

What do you mean by Rigid Pavements?

There is a great deal of flexural strength or flexural rigidity in rigid pavements. The load on this pavement is distributed by the slab action, and the pavement acts as an elastic plate that distributes the load evenly.

Concrete made of Portland cement and gypsum (PCC) is used to construct rigid pavements. In either case, the pavement materials are placed either directly over the prepared subgrade or on a single layer of granular or stabilized surface that has already been prepared. By means of slab action, the wheel load is transferred to the sub grade. There are joints involved in the process. The cost of construction is high at the beginning of the project. The rigid pavement has a high level of tensile strength.

What are the varieties of Flexible Pavement?

There are generally four varieties of Flexible Pavement, they are as follows:

1. Pre-stressed concrete pavement
2. Continuous reinforced concrete pavement
3. Jointed plain concrete pavement (JPCP)
4. Jointed reinforced concrete pavement (JRCP)

Rigid Pavement vs. Flexible Pavement

Flexible Pavement	Rigid Pavement
Grain to grain mechanism is used to transfer the wheel load from one wheel to another.	It is through the slab action mechanism that the load is distributed.
Flexible Pavement is much more less durable.	Rigid Pavement is very more durable in strength.
There is a low flexural strength in these materials.	A sufficient amount of flexural strength should be present.
Require frequent repairs in order to function properly.	It does not require frequent repairs and does not require much maintenance.
The Repair and maintenance costs are high due to the age of the equipment.	There are no maintenance or repair costs associated with this product.
It is a well known fact that deformations in the subsoil are transferred to the upper layers as a result.	Sub grade deformation is transmitted to the subsequence as a result of sub grade deformation layers.
It is generally thicker in width.	It has a very low thickness level.
It is possible to open the road to traffic shortly after construction has been completed.	This requires curing, which results in a delay in traffic opening due to the curing process.
It is easy to lay underground pipes under flexible pavements, find them, and repair them if necessary.	There is a difficulty in repairing underground pipes under rigid pavements.

The skills required are normal and supervision is not necessary.	A skilled workforce is needed in order to complete the project.
As a result of the asphalt's colour, it provides poor visibility at night.	The visibility of concrete at night is very good, but it is still not at par with Flexible pavement.
Flexible pavement can get damaged by chemicals and oils.	In Rigid pavement, there is no damage caused by any chemicals such as greece or oils.
An evaluation of the subgrade strength is used in the design process.	Flexural strength is taken into account when designing the structure.

To learn more, watch the following video tutorial.

Video Source: My Engineering Support

Stresses are not caused by temperature changes.	Heavy strains are brought on by temperature changes.
A bituminous material, such as asphalt, is used to construct this structure.	Portland cement was used in the construction of this structure.

Repair and maintenance costs are high due to the age of the equipment.	The cost of repairing and maintaining the system is low.
By using a grain-to-grain mechanism, the wheel load is transferred from one wheel to another	A slab action mechanism distributes the load on the slab in a uniform manner.
The creation of stages is practicable.	The creation of stages is not practicable.