Asphalt is one of the most commonly used pavements for driveways, roads and parking lots. Despite its prevalence in our cities and neighborhoods, many people don’t know what asphalt is made of or how it’s manufactured. Asphalt pavement may be a mysterious mixture—until you need to resurface a driveway or repair a pothole.
Learn asphalt paving basics below, including its ingredients and how manufacturers make the mixture you drive on every day.
What Is Asphalt Paving?
Asphalt is a semi-solid form of petroleum. It has a few basic ingredients, including a mixture of crushed stone, gravel, sand and a material called bitumen. Bitumen is a sticky, black byproduct of petroleum that holds the aggregate together. Asphalt is typically modified and mixed in batches at special processing plants.
How Is Asphalt Paving Manufactured?
Before asphalt is mixed at the manufacturing facility, plant operators identify which type of asphalt they need to create. They measure ingredients based on the project and climate at the project site. For example, different asphalt must be mixed for a project in Alaska compared to a project in Arizona.
Hot liquid asphalt is combined with heated aggregate in an asphalt plant to produce a paving mix typical called hot mix asphalt (HMA). Hot mix asphalt (HMA) is loaded directly into a truck or stored in heated silos until it’s ready to be applied to roads, interstates and parking lots.
What Are Uses of Asphalt Paving?
There are several common uses of asphalt on the market, depending on the type of asphalt you need. Asphalt types include:
- Hot mix asphalt
- Warm mix asphalt
- Cold mix asphalt
Hot mix asphalt is flexible, water repellant and used on highways and city streets. It’s heated and poured at temperatures up to 350° Fahrenheit. Warm mix asphalt is manufactured at lower temperatures and cools more slowly than hot mix. Additionally, warm mix asphalt can be shipped more easily than hot mix and is more environmentally friendly. Finally, cold mix asphalt is an affordable, user-friendly mix for pothole repairs and winter projects. Cold mix asphalt can be packed into bags for retail sale.