What is Road Pavement
Pavement, also known as a road surface, is a long-lasting surface material that is laid down on an area to support vehicle traffic. Pavement is made up of various components and layers. Its primary function is to distribute the applied vehicular loads to the layers beneath.Ground-work, laying materials, and other steps are involved in the construction of a road pavement. Ground-work is done to prepare sub-surfaces for road construction to begin.
It is an important job that must be done correctly in order to make the road surface last longer. As a result, we should always hire a good groundwork specialist for this task.
Components Of Road Pavement Structure
The following are the various road structure components:- Sub-grade
- Sub-base
- Base course
- Surface course or wearing course
Sub-grade
Subgrade or formation refers to the finished and compacted earthwork surface on which a road pavement rests.Depending on the topography and finalized formation level, a road's subgrade may be provided on an embankment, in cutting, or on existing ground level. It is made up of well-compacted natural soil that has been shaped to the desired camber and gradient.
Because the entire load of the pavement, including the load of traffic transmitted through the pavement, is eventually taken up by the subgrade, the thickness and type of pavement structure are determined by the supporting power of the subgrade.
Sub-base
When the subgrade is of poor quality, it is provided as an additional layer. It is made up of a layer of less expensive material, such as burnt clinker, natural gravel, or slag.
Base Course
A base course, soling, or foundation course is a layer of boulders or bricks provided over the subbase or immediately over the subgrade in the absence of a subbase in road pavement.This course is regarded as the most important and significant component of road structure because it is responsible for absorbing the impact of traffic transferred through the wearing course.
It is made of a stable material such as boulders, gravel, one or two layers of well-burnt bricks, and so on. This course is not available if the subgrade is rocky.
Surface Course Or Wearing Course
The wearing course or surfacing is the topmost layer of the road pavement that is directly exposed to traffic. In the case of Flexible pavements, it may consist of one or more layers.A good wearing course should be impervious to water and weather. It must be able to withstand the abrasive action of traffic.
Purpose of Road Pavements
The following are the various functions of road pavement.- The primary function of road pavement is to transport heavy loads from vehicular traffic to the subsoil strata.
- To avoid the negative effects of weathering agencies on sub-grade soil.
- To provide a smooth surface for vehicle movement.
- To spread the load across a large area of the underlying soil strata.
Road Pavement Applications
Road pavement has a variety of applications, including the following.- The road pavements are built to withstand the heavy load of vehicular traffic movement.
- It offers a slick surface on which traffic can move.
- It prevents rainwater from building up on the surface.
- The pavement on the roads aids in the efficient movement of vehicles.
Types of Pavements (Road Pavement)
There are two main categories for road pavements, which are as follows.
- Flexible pavement
- Rigid pavement
1. Flexible Pavements
The loads generated by vehicle movement are transferred to the subgrade soil in the case of flexible pavement. The load is transferred to the subgrade grain by grain via the granular structure's point of contact.
Bituminous roads, water-bound macadam pavements, and gravel pavements are common examples of flexible pavements. Flexural strength is lower in flexible pavements.
The flexible pavement design is based on the layered system concept, in which the total load acting on the pavement is a transfer from grain to grain to the beneath strata.
The flexible pavement is classified into the following subtypes:
The conventional layered flexible pavement is built in a layered system that includes subgrade (the bottom layer of the pavement), subbase, base course, and base coat, among other things. During the construction of a conventional layered flexible pavement, high-quality materials are placed at the top layers and low-quality materials are placed at the bottom layers.
ii. Full-Depth Asphalt Pavement
Full-depth asphalt pavement is a flexible pavement type in which the bituminous layer is built directly on the subgrade layer. This type of layer is appropriate when the material is unavailable and the project's construction cost is low.
The contained rock asphalt mat is built by sandwiching dense and open-graded aggregate layers between two layers of asphalt. Over the subgrade, the asphalt concrete layer is designed and laid. The asphalt concrete reduces the compressive strain on the subgrade layers while also protecting them from water. The asphalt layer acts as a barrier, preventing water from entering the pavement's subgrade layers.
The flexible pavement design is based on the layered system concept, in which the total load acting on the pavement is a transfer from grain to grain to the beneath strata.
Types of Flexible Pavements
- Conventional layered flexible pavement
- Full-depth asphalt pavement, and
- Contained rock asphalt mat (CRAM).
i. Conventional Layered Flexible Pavement
Full-depth asphalt pavement is a flexible pavement type in which the bituminous layer is built directly on the subgrade layer. This type of layer is appropriate when the material is unavailable and the project's construction cost is low.
iii. Contained Rock Asphalt Mat
2. Rigid Pavements
Rigid pavement refers to road pavement that cannot change shape without rupturing. Rigid pavements are better able to transfer heavy loads of vehicular traffic to a larger area.
Rigid pavement is an example of cement concrete pavement. The flexural strength of the cement concrete road pavement is high. Rigid pavements can be built directly on top of a compacted subgrade or granular layer.
Because rigid pavements have high compressive strength, they are better suited for heavy-load traffic movement. The rigid pavements required less maintenance as well.
Types of Rigid Pavements
Rigid pavements are classified into four types.- JPCP (joined plain concrete pavement)
- JRCP (joined reinforced concrete pavement)
- CRCP stands for continuous reinforced concrete pavement.
- PCP stands for pre-stressed concrete pavement.
ii. Jointed Reinforced Concrete Road
The purpose of the dowel bars is only to transfer loads, and the reinforcement used in the slab helps to keep the road pavement together. The reinforcement has no effect on the road's structural stability.iii. Continuous Reinforced Concrete Road
There are no joints in the continuous reinforced concrete road pavement. The continuous reinforced concrete road pavement incorporates these reinforcements.
iv. Pre-Stressed Concrete Pavement
The stresses are induced in pre-stressed concrete road pavements to increase their properties so that they can withstand heavy loads caused by vehicular traffic movement.
Difference between Flexible Pavements and Rigid Pavements
