Last Updated on December, 2024
Whether we’re walking, driving, or taking off on an aeroplane, we see and interact with asphalt surfaces daily. They are vital to urban life, but most people know little about them.
Understanding this material is vital to ensuring proper installation and repairs, especially if you plan to add an asphalt driveway to your property.
This article will explore how asphalt is made, its pros and cons, its typical applications, and more. Let’s dive in!
Quick Summary
- Asphalt is a composite material made from aggregates like sand, gravel, and bitumen (a binding agent). It can include recycled materials for sustainability and is produced by heating and mixing these components in asphalt plants.
- There are three primary types, Hot Mix Asphalt (HMA), Warm Mix Asphalt (WMA), and Cold Mix Asphalt (CMA). Each differing in production temperature and application suitability, with HMA being the strongest and most durable.
- Asphalt is widely used for roads, driveways, parking lots, and roofing. It is durable, sustainable, and requires low maintenance but has higher upfront costs and a shorter lifespan compared to concrete.
Asphalt: What is it and How is it Produced?
Asphalt (asphalt concrete) is a composite material made of aggregates such as sand, gravel, crushed stone, and more. Recycled materials like slag, waste plastic, and tyre rubber are also used to make asphalt sustainable and reduce environmental impact.
The aggregates are combined with a binding agent called bitumen. Commonly known as tar, bitumen is a dark, viscous liquid that contains polycyclic hydrocarbons. Its adhesive properties help hold the asphalt mixture together.
The aggregates are heated and dried to remove moisture. The bitumen is heated in a separate tank to make it thinner and suitable for asphalt production. Afterwards, the materials are mixed in a stationary asphalt plant or a mobile mixing plant.
New materials may be added to the mixture to achieve specific properties and improve performance characteristics. Asphalt mixes are then stored in heated storage tanks and prepped for transportation.
While the production process for different asphalt mixtures can vary, using aggregates (sand, gravel, crushed rock) and bitumen is standard.
Types of Asphalt
Asphalt is a predominant material in road construction, but the properties of specific mixtures will change depending on project requirements.
There are three main asphalt types. Let’s have a look!
Hot Mix Asphalt (HMA)
Hot mix asphalt requires extreme heat to produce (150 to 180 ℃) and is the strongest asphalt type. Its flexible and waterproof properties make it the top choice for heavy-traffic applications like parking lots, highways, and driveways.
Warm Mix Asphalt (WMA)
Warm mix asphalt is made at much lower temperatures. As such, WMA production uses significantly less energy and reduces greenhouse gas emissions. While not as durable as HMA, it is still commonly used as asphalt paving for parking lots, walkways, and driveways.
Cold Mix Asphalt (CMA)
Cold-mix asphalt (CMA) is made by emulsifying the bitumen content in water instead of adding heat. The water evaporates during the curing process and strengthens the mixture, resulting in a hard surface. CMA is mainy used for patching or sealing small cracks in pavements.
Common Uses and Applications of Asphalt
Here are some common uses and applications of asphalt.
Highways and roads: Asphalt is the most popular road surface material worldwide. Its strength, flexibility, and longevity allow it to bear the weight of heavy vehicles without cracking.
Driveways: Asphalt is an excellent driveway paving option. It can withstand harsh weather conditions and requires minimal maintenance.
Parking lots and playgrounds: Porous asphalt has excellent drainage and removes the risk of surface water, making it ideal for parking lots and playgrounds.
Bicycle lanes: Warm mix asphalt can provide a smooth surface for bike traffic.
Airport runways: Most airports use asphalt concrete for their runways due to its load-bearing and skid-resistant properties.
Roofing: Mastic asphalt is an affordable option for flat or low-slope roofs. It is waterproof and can last more than 50 years with proper maintenance.
Crack filling: Asphalt can be used as crack filler to seal pavements and for other repairs, such as patching.
Pros and Cons of Asphalt
Though this material has many positives, there are also some negatives.
Pros
Here are the advantages of asphalt.
Durability: With the proper aggregates and installation, it can tolerate temperature fluctuations and large traffic volumes without compromising the pavement structure.
Sustainability: Old materialscan be recycled to create new asphalt. Modern technology has also optimised asphalt production by reducing fuel consumption, making the process more environmentally friendly.
Low maintenance: When properly installed, these surfaces require little maintenance and will save you money in the long run.
Safety: Asphalt is one of the safest pavement options due to its skid resistance and ability to tolerate high temperatures.
Cons
Now, let’s look at the drawbacks.
More expensive upfront: Alternatives like concrete may be more cost-effective upfront.
Shorter lifespan than concrete: Depending on its installation and wear and tear, asphalt pavement may not last as long as concrete pavement.
Installation and Maintenance Tips for Asphalt Pavement
During installation, it’s important to consider the different layers of your pavement: the base course, binder course, and surface course (or top layer).
Asphalt maintenance is also necessary to ensure a long life for your pavement. You can stay ahead of repairs by filling cracks and sealing the asphalt surface every two to three years.
Relevant guides:
Conclusion
Asphalt is a versatile and durable material with many applications. We hope this article has helped you better understand whether it’s the right material for your project.
Although it may be more costly upfront, it will provide a robust and resilient surface that will last for years.
