A modern economy cannot operate without the mass movement of people and goods. To move people and goods fast and comfortably, private and public entities have deployed capital to build paved roadways. But what is considered a paved roadway?
A paved roadway is a road built using durable surface materials such as asphalt and concrete to facilitate frequent vehicular and foot traffic. Such a road has a sub-base under the top asphalt or concrete layer to provide stability and prevent deterioration.
Ever since we moved to Delaware, I have seen many types of roads. From very well-paved roadways to very poor dirt roads that barely qualify as roads. This experience made me ask what is considered a paved roadway.
Paved roadways have improved significantly since they first appeared in ancient Mesopotamia in 4,000 BC. In most of the world today, paved road construction has been standardized and follows specific best practices. Let’s go over the main characteristics of a paved roadway.
Three Defining Characteristics of a Paved Roadway
For longevity and functionality, there are specific standards that construction companies must meet when building paved roadways. While climate, soil conditions, and geography may require specific variations, a paved roadway will typically have the following three characteristics.
Paved Roadways Are Built Using Durable Materials
Modern paved roads use durable materials such as concrete and asphalt. Concrete on paved roads is created using a mix of aggregate, sand, and portland cement. On the other hand, asphalt is made using a composite of aggregate and bitumen.
These materials are durable enough to sustain paved roads for the required service life of about 18 to 25 years. With timely repairs and maintenance, local authorities can significantly extend the service life of a paved road. To last this long, paved roads should be durable enough to handle temperature extremes, rainwater drainage, and consistent vehicular traffic.
Paved Roadways Are Skid Resistant
Paved roads are skid resistant to reduce the chances of a crash due to skidding. The aggregate used in the concrete or asphalt mix helps increase friction between tires and the road, thereby improving skid resistance.
Skid resistance disappears over time as the road surface gets worn out under constant vehicular traffic. Maintenance crews can maintain the skid resistance by doing the following:
- Retexturing: this involves restoring the frictional ability of a road surface by removal of deposits using bush hammering and high-pressure water jetting.
- Resurfacing: this involves recarpeting the road using a surface treatment to restore the surface texture to almost new. Some roads have high-friction surfacing (HFS), an aggregate that causes more friction, thereby increasing skid resistance.
Modern Paved Roadways Have Acoustic Absorption Properties
Besides the noise generated by car engines, vehicles also generate noise because of the tires rolling on the pavement. Road builders can reduce noise by engineering paved roads with acoustic absorption properties.
Texture and porosity determine the noise reduction capabilities of paved roadways. Currently, existing solutions for reducing road noise take advantage of porous asphalt. Porous Asphalt concrete has more voids because it uses aggregates of different textures and homogeneity.
The tread-on-surface noise on the road results from the air vibrating as the tire compresses it on the road. Porous asphalt has voids that allow the air to escape, reducing noise.
The Five Key Steps Involved in Building a Modern Paved Road
For a paved road to last for its expected service life, the construction from the ground up has to follow industry best practices. Besides the road being able to carry vehicles, the builders must consider other factors such as rainwater drainage and road noise reduction. Below are the five critical steps involved in building a modern paved roadway.
1. Planning and Design
The planning phase involves evaluating the expected traffic volume, routing considerations, geographical and environmental factors, and the funding available for the project. After considering the route, budget, utility, and geographical limitations, the builders design the road with those constraints in mind.
A good road design should account for the following:
- Expected traffic volume
- Geographical terrain
- Floodwater and rainwater drainage
- Current and future utility lines
- Future expansion plans
- Ease of maintenance
- Harmonious coexistence with people and animals by limiting noise pollution and making it easy for people and animals to cross the road
With the final plan and design in hand, the company or government building the road can estimate how much the project will cost and allocate funds accordingly.
2. Earthwork and Building the Sub-Base
This phase involves clearing the area the road is supposed to pass of trees and other vegetation, excavating the site, smoothening the surface, and building the sub-base in the excavated area. The sub-base is built using aggregate, limestone, and concrete composite. It gives the road stability and provides a solid base upon which the top asphalt or concrete paving layer can sit.
3. Paving the Road Using Asphalt or Concrete
After constructing the sub-base, the builders pave the road using asphalt or concrete. When using asphalt, they consider the weather conditions and expected traffic volume to determine how many layers of asphalt to lay. Usually, up to three layers of asphalt are ideal.
4. Joining the New Road to Adjacent Roadways
At this stage, the builders join the road to the rest of the road network in the area, including pavements, driveways, and parking lots. Repaving the joints between two roads ensures smooth transitions. Further, the builders put up new drainage infrastructure where necessary.
5. Testing the Road Before Opening It to the Public
Before the local authority opens the road to the public, it must test it for utility and safety. The road should be smooth while providing adequate skid resistance to prevent skidding accidents.
To evaluate the smoothness of the road, the people testing the road drive a vehicle carrying seismology equipment over the road. The equipment measures the level of vibration when driving over the road. The builders will smoothen the road further if the vibration is beyond the recommended level.
Paved roadways have durable surface treatments that make them ideal for the modern world with heavy vehicular transportation. Modern paved roads consider several factors, including the need to reduce noise pollution, ease of maintenance, and harmonious coexistence with people and animals.