How Is Asphalt Made?

October 9, 2019

Asphalt is essentially ubiquitous—you see it everywhere you go on the roads you drive on, the sidewalks you walk on and the parking lots at businesses, schools and more. You see it so much that you probably don’t spend a whole lot of time thinking about where it comes from or how it’s made.

Understanding how asphalt is made can give you a bit more of an appreciation for how it’s used. Here’s some information about the process of making asphalt, from an asphalt contractor in Montgomery County, MD.

Developing asphalt

Most of the asphalt you see used to day gets processed from petroleum. Oil wells send up crude oil to refineries, where that crude gets separated into several parts as part of the refining process. The heaviest part of the petroleum that gets separated is used to make asphalt.

That material can get modified in several ways. Manufacturers can add a cutting agent that makes the material more malleable, or it can be pulverized or emulsified until it achieves the right consistency to be worked with. If the asphalt will be used for paving projects, it will be put through a mixing process in a batch plant (used for smaller outputs in batches) or a drum mix plant (a continuously operating facility that creates large asphalt outputs).

There are several different methods that can then be used to mix the asphalt until it’s in the proper state. There are hot-mix and cold-mix methods, which are the two most popular methods used for mixing.

Hot-mix asphalt is made by heating up aggregates to decrease binding agent viscosity and make it more fluid. The material then gets dried out to remove moisture. It gets mixed while it’s between 200 and 350 degrees Fahrenheit, and is called hot-mix not just because it’s mixed while it’s quite hot, but also because it must stay hot during the paving and compaction process. This is why you tend to see most asphalt paving and compaction jobs taking place during the summer—it’s much easier to keep the asphalt hot while the outdoor temperatures ares also warm.

Cold-mix asphalt, meanwhile, is made up of a quarter-inch chip and oil, which keeps the asphalt soft and impermeable to water. Cold-mix asphalt does not need to be warm when used for the asphalt repair process. Instead, the additives found in the mixture help it to stay soft all year long, which makes it ideal for patching potholes, regardless of the temperature outside. This is especially beneficial for road repair jobs in winter and early spring, when the roads tend to be in their worst condition. The patch remains flexible all year long, and also helps to keep water out of the hole underneath.

For more information about the processes associated with manufacturing asphalt and the benefits of these different approaches to creating and mixing the material, we encourage you to contact a trusted asphalt contractor in Montgomery County, MD at Maryland Asphalt LLC. We look forward to working with you soon!

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