How is Asphalt Made?

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Photo of Laying Asphalt
  • Asphalt is used to pave roads, construct roofing materials, and pave parking lots, but many people are unaware of the steps required to make this popular material.
  • The most common sources of the raw materials for asphalt are natural deposits or petroleum industry byproducts.
  • Neyra Paving offers industry-leading paving services and high-quality asphalt for residential or commercial applications that are built to last.

How Is Asphalt Made?

It provides a durable surface for our streets and has been used for millennia in civil engineering, but this black material remains a mystery to most individuals. How is asphalt made? Explore the manufacturing steps, common materials, and benefits of purity in the process today. Turn to a leading asphalt paving team in the Cincinnati, OH, area to learn more and schedule a paving project.

What is asphalt made of? It all starts deep in the ground. Asphalt is made using products from one of two sources:

  1. Natural deposits
  2. Byproducts of petroleum industry production, such as petroleum asphalt

This heavy, dark brown, or black material is removed from deep in the earth and used as a binding material. History tells us ancient Sumerians and Egyptians used it in shipbuilding, road construction, and other building projects.

Combined with aggregate, asphalt can create a durable and cost-effective road. It’s also commonly used to create shingles and other roofing materials. Find out how the production process transforms raw materials into these useful construction products for roadways and other applications.

Distill Crude Petroleum

The most common asphalt is a byproduct of the oil refining process. As refineries distill oil, they separate crude petroleum into a range of products. It starts with crude petroleum delivered into a storage tank with a tube heater or heat exchanger. An atmospheric distillation tower separates products. Here are just a few byproducts of the refining process:

  • Diesel oil
  • Kerosene
  • Gasoline
  • Paraffin
  • Asphalt

Topped crude is one of the heavier residues from this process. Removed at this point in the process, it becomes fuel oil. Further refining transformed it into asphalt and other products.

Blend Products

Asphalt at this stage is hard and difficult to work with unless at high temperatures. Most asphalt is blended with a volatile substance at this point to create a more workable product for commercial and residential construction projects. This volatile substance evaporates over time when exposed to air, which causes the asphalt to harden unless exposed to extreme heat levels.

This is an ideal feature for paving. It allows expert contractors in the Cincinnati area and elsewhere to pour and work asphalt into the desired shape. The evaporation process solidifies the shape and creates a reliable roadway. The amount and type of volatile substance determine whether the asphalt is considered rapid, medium, or slow curing.

Emulsify the Asphalt

Roads aren’t made with pure asphalt. It needs to combine with stone and gravel, or aggregate, to create a durable surface. This is achieved by emulsifying the asphalt. The first step is to thoroughly grind it into globules no more than 10 microns large.

These tiny globules are mixed with water and an emulsifying agent. Typical agents used include sulfonated vegetable oils, silicates, soap, or colloidal clay. Emulsifying agents prevent the water and asphalt from separating, allowing the product to mix easily with aggregate and be pumped through pipes.

Pulverize It Into Powder

An alternative to emulsifying, pulverizing is another way to prepare asphalt for construction projects. This strategy creates powdered asphalt. It can then be mixed with road aggregate and road oil to create pavement. Binding these materials together with heat and pressure creates a surface similar to typical asphalt.

Optional Air Blowing

Another option for asphalt construction projects is air blowing. This process creates asphalt that remains soft at higher temperatures. It’s heated to temperatures around 500 degrees Fahrenheit and bubbled for several hours. Air-blown asphalt isn’t usually used for paving but is used in waterproofing, sealing, roofing, and pipe-coating applications.

Why Asphalt Quality Matters

A number of products are mixed together and processed to create paving asphalt. Because of the many steps involved, there are many opportunities for errors and inconsistencies in the process. Find out why Neyra Paving in Cincinnati, OH, is committed to the highest levels of asphalt quality in every paving project.


Pure asphalt is safe asphalt. Precision in the manufacturing and application processes is critical to ensure the proper durability ratings are reached. A pothole in the surface or sudden crack in the foundation of an asphalt surface can be dangerous for drivers or pedestrians.

Safety becomes even more critical if you’re using asphalt in a complex installation project. Asphalt on a bridge, roof or other elevated surface requires dependable durability features. Failure to create efficient asphalt that meets safety standards could risk serious injuries and costly property damage. From a short driveway to a serious civil engineering project, be sure you’re working with a pavement team that only uses the highest quality pavement.


Inconsistent asphalt may create weak spots in the road’s surface or parking area being constructed. Even minor inefficiencies can remove years from the expected lifetime of an asphalt structure. Don’t let inferior quality materials create a dangerous or inefficient structure, but turn to a leader in paving services for peace of mind.

Choose high-quality asphalt for an improved investment. Pouring, compacting, and finishing an asphalt surface requires professional expertise and heavy machinery. When you cut corners and choose a low-grade asphalt product, you significantly reduce the time between installation processes. It’s usually more expensive, over time, to choose a low-grade asphalt product.

Asphalt Mixture Types

Pure asphalt can be made in multiple ways to achieve different construction goals. In paving, there are two typical mixture options. Compare hot-mix and cold-mix asphalt and ask your construction team which option they plan to use for your parking area, driveway, or commercial road.

Hot Mix

Hot mix is the more common type of asphalt used for commercial purposes. Manufacturers heat the aggregate and asphalt before they’re mixed. This step removes excess moisture to create a more efficient product. The mix needs to be compacted at the job site while still hot to ensure a good spread over the work surface.


Cold-mix skips this step and uses cut-back or emulsified asphalt. Typical cold-mix applications include lightly used roads, maintenance purposes, and remote use. Asphalt that is cold-mixed is typically more affordable but doesn’t offer the same longevity or weight rating as hot mix asphalt.

Choose Industry-Leading Asphalt With Neyra Paving

Now that you understand the various asphalt materials available to you and the steps required to create them, it’s time to prepare for a quality asphalt project. Request an estimate from Neyra Paving for any pavement installation, repair, or maintenance project in the Cincinnati area. Turn a cracked surface or a dirt driveway into a smooth, safe, and durable driving surface that adds value to your commercial or residential property. Reach out by phone by calling (513) 733-1001 today.

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