You see it everywhere. When you’re driving around town, when you’re walking through the park, on the roofs of your buildings, and even on the bridges in your city. Asphalt paving is one of the most widely used construction materials out there, but how is it made? In this article, you’ll learn all about asphalt and what goes into making it.
Where is Asphalt Paving Used?
Asphalt is a very versatile material that is used in industrial and recreational settings alike! Some of the most common uses of asphalt paving are:
- Roads
- Parking Lots
- Airport Runways
- Walking Trails
- Biking Trails
- Tennis Courts
- Roofing Materials
- Bridges
- Ramps
Why is Asphalt Paving Used?
Asphalt is a popular option in the construction industry for many, many reasons including its environmentally-friendly and economically-friendly benefits! Asphalt is one of the most recyclable materials out there. According to the Federal Highway Administration, around 80% of all asphalt paving projects use recycled materials! The reuse of this much asphalt saves American taxpayers over $2,000,000,000 (yep, that’s two billion dollars) annually. Not to mention that asphalt’s ingredients can be recycled over and over and over.
Asphalt paving is a very safe option for making roads and trails. It creates a safe surface for vehicles to travel on at high speeds, and it decreases the chance of automotive accidents by reducing puddling in wet weather.
Asphalt is low-cost and low-maintenance! An asphalt surface can last up to 20 years with the proper care, and after that the materials can be recycled and renewed on site. Not to mention that recycled asphalt is often stronger and more durable than virgin materials.
How Asphalt Paving is Made
The making of asphalt pavement starts with the distillation of crude oils. The oil goes through the process of distillation, which separates all of its different components. After most of those components are removed, there are heavy deposits left over – one of these is asphalt! Asphalt is made up of hydrocarbons (or bitumen, the scientific name for the solid petroleum deposits). This deposit material is resistant to extreme weather and temperatures!
Technically, asphalt is only one ingredient in asphalt pavements. The other main ingredient is called aggregate – a mix of different hard minerals (like sand or rocks) that give pavement its strength and durability.
There are two different types of asphalt – hot and cold mixes (HMAs and CMAs). HMAs are used in high-traffic areas like interstates and main roads. To make this type of asphalt pavement, the asphalt is heated to a liquid form (requiring temperatures of about 300°F).
The hot asphalt and the aggregate are then mixed together, usually in a large mixing drum ( you know, those spinning trucks you see at construction sites) while being transported promptly to the project location. While still hot, the pavement mixture is poured. Before it cools, multiple compaction roller machines pass over the pavement to ensure it becomes as densely packed as possible. Then, the project is left to cool and harden.
Another way of “making” asphalt pavement is to recycle it! There are two main methods of renewing asphalt materials. The first is milling, in which the top layer of asphalt is scraped away, leaving the sub-base layer undisturbed. The scrapings are then taken to an asphalt plant, where they can be recycled for future projects.
The second, most popular asphalt pavement recycling method is pulverization! Pulverizing equipment can be used onsite to grind up the layers of asphalt and create an entirely new material that can renew the road to a stronger, more durable version than before! This method saves time, resources, and money.
Overall, asphalt is one of the most durable, most universally-applicable, and most renewable resources in the construction industry!
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