The Process of Making and Mixing Asphalt

Top view of builders in orange shirt pouring concrete works on the construction site

Asphalt is a material used to bind crushed stone and gravel (aggregate) to create a solid hard surface. It’s a dark heavy mixture of hydrocarbons (bitumen) obtained from petroleum distillation or natural deposits. Asphalt is used in construction jobs, such as building dams and bridges.

Asphalt making process

Several steps are involved in making asphalt, including distillation, cutting back, emulsifying, pulverizing, and air blowing.

In the distillation process, crude oil is heated rapidly to raise the temperature for initial distillation. More volatile and lighter components are removed from the heated crude oil through condensers and coolers. The crude is refined into diesel, kerosene, gasoline, fuel, and other petroleum products.

Asphalt is then blended, called cutting back, with a volatile substance, resulting in a product that’s malleable enough for use. It can also be emulsified to create a product that can easily mix with aggregates, pumped through pipes, or sprayed through nozzles.

Hardened asphalt is pulverized and passed through fine-mesh sieves to produce uniform-sized granules. Heat and pressure are applied to the asphalt to amalgamate the powder with aggregate and binding oil, resulting in a hardened substance. It is heated to 500 ⁇ F; then air is bubbled through it for a few hours. The asphalt remains in a liquid state when cooled.

Asphalt mixtures

Asphalt mixtures can be categorized either as a hot or cold mix. The hot-mix asphalt (HMA) involves heating asphalt and the aggregate to dry the aggregate and obtain adequate fluidity of the asphalt cement for proper mixing and spreading. It’s commonly used for high-traffic areas, such as highways and roads.

As the name suggests, cold-mix asphalt (CMA) requires less heating and is made of quarter-inch chip and proprietary oil that keeps the asphalt soft and enables it to repel water, allowing for pothole patching in different types of weather. This makes it suitable for paving secondary roads.


As one of the oldest engineering materials, asphalt is widely used in various construction jobs and small or large projects requiring a smooth flat surface. Kilgore companies are experts in multiple projects, from local to large-scale projects. Contact Kilgore companies to learn more about asphalt and help you with your next project.