A pavement can be defined as a resistant surface that has been made with durable materials and whose construction objective is to allow the transport of vehicles, people and animals.
Physically and mechanically a pavement has the objective of distributing the loads applied to the ground through the use of different layers and that does not exceed the load capacity of the subgrade material.
The structure of a road pavement must have the capacity to provide sufficient slip resistance, adequate characteristics to reflect light, adequate resistance and quality, and low noise pollution.
Properties and characteristics of a good pavement
The following is a list of the properties and characteristics that a good pavement must have in the construction and engineering industry.
- In order to adequately distribute the loads and stresses generated in the soil and the pavement must have an adequate thickness.
- It must be structurally strong to withstand all kinds of stresses placed on it.
- In order to prevent vehicles from skidding, it must have a sufficient coefficient of friction.
- It must have a smooth and level surface that offers comfort to road users even at high speed.
- It ensures less noise when the vehicle moves on it.
- It must be dustproof so that there is no danger to traffic safety.
- It must provide an impervious surface, so that the subgrade soil is well protected, and
- It should offer minimal maintenance and a long service life.
Components and parts of the pavement
Despite the fact that the design and structure of the pavement will depend in many cases on the type of uses that it is intended to give, the truth is that it has a general structure in the form of layers. These layers are designed and calculated with geotechnical and civil engineering studies that give them high resistance and durability.
The main layers and components of the pavement are shown below.
- tread layer
- base layer
- sub-base layer
- compacted soil
- subgrade layer
The surface layer or also called asphalt coating is the one that is in charge of waterproofing the pavement structure with the objective of the lower layers retaining their load capacity. Also, on the surface it becomes an anti-slip coating that works well in wet conditions. Finally, it is in charge of reducing the vertical tensions and thus allows to control the plastic deformations in the layer and in the lower layers.
The base layer is the one that is responsible for reducing the effect of vertical loads and tensions towards the lower layers. In addition, it reduces deformations that can be caused by loads on the coating layer. Finally, it is a layer that allows the drainage of water that has managed to infiltrate the pavement through the use of lateral drains.
The sub-base layer is made with a material that has a load capacity much higher than that of compacted soil in order to avoid reducing the thickness of the base layer.
The subgrade layer is basically the soil that serves as the base to settle the entire pavement structure and the upper layers.
Types of pavements
Currently there are 3 types of pavements that are used in construction engineering. These are flexible pavements, rigid pavements Y mixed or semi-rigid pavements. However, depending on the needs, many other types have also been created. The properties and characteristics of each of them are described below.
Flexible pavement and its properties
Flexible pavement is one in which loads are transferred to the subgrade material with the theory of grain-to-grain transfer through contact points in the granular structure of the subgrade.
Highways and roads covered with the flexible pavement is characterized by having less resistance to bending, that is to say that it acts as a material similar to a flexible sheet. An example of this are the bituminous roads.
Another characteristic is that the load caused by the wheels on this material is distributed over a larger area and therefore the stress decreases with depth. Taking into account this charge distribution characteristic of the flexible pavements, has many layers.
Regarding its design, flexible pavements are built on the basis of a layer system, where the pavement as such is the one that must support the maximum compression stress and is the one that must have the highest quality between the layers. Thus, the lower layers can be tolerated to be of lower quality.
Finally, the materials that constitute this type of pavement are mainly bituminous materials.
Rigid flooring and its characteristics
This type of pavement is characterized by transferring the load to a larger area due to its excellent resistance to flexion. Unlike a flexible pavement, it is not made with many layers of materials.
Therefore, rigid pavement is placed directly over a subgrade material that is either compacted or over a single layer of granular material. Since there is only one layer between the concrete and the subgrade, this layer can be referred to as the base layer or subbase.
On rigid pavement, the load related to vehicular traffic causes the road to behave like an elastic layer resting on a viscous medium. For this, it is built using simple portland cement.
Regarding its design, it is done by applying the plate theory instead of the layer theory as it is done with flexible pavement, assuming an elastic plate supported on a viscous base layer.
Semi-rigid flooring
This type of pavement is also called combined, mixed or semi-rigid. It is basically a type of pavement that is built when a thin flexible pavement layer is laid on a rigid pavement base.
Although it can have many advantages, it is rarely executed because it requires detailed and complex analysis and because its cost is usually higher.
Porous or permeable pavement
This type of paving is one that allows water to penetrate the material from the surface and be channeled into the ground instead of being directed directly into a culvert. The advantage is that water does not accumulate on the surface.
It is mainly used in places with light vehicular traffic such as parking lots where long-term heavy loads cannot damage its structure.
Hot mix flooring
It is also known as asphalt or bitumen pavement. This material is characterized by being durable and very economical, its use is very popular in cities but it can be used for almost all types of objectives.
In addition, it has the advantage that it can be manufactured with recycled asphalt material. It is basically hot mixed at intermediate temperatures of 150°C.
Concrete pavement
This material is often used in local low traffic areas and is generally classified as JPCP, JRCP, or CRCP depending on its joining systems. Joint systems are there to help prevent cracking and concrete tends to be a long-lasting solution, requiring little maintenance, albeit its high cost. it can be prohibitive.
Pavement uses
Despite each type of pavement can be used for a specific or more appropriate activity, the truth is that in general the pavement is used on roads, highways, roads, parking lots, tunnels and even for the patio of houses, buildings, factories and industries.
They are also used on roads in the mining industry, in the oil industries, quarries, etc.