6 Types of Asphalt For Residential Projects

As you’re driving down a residential street or freeway, you don’t typically consider the smooth, durable surface underneath your tires. Though, believe it or not, there’s much more to asphalt pavement than meets the eye. Aside from being one of the most widely used paving material in the world, there are numerous types of asphalt out there that can be tailored to different situations.

Not all asphalt mixes are the same, as they serve individual purposes and come in varying levels of quality. Generally speaking, the three main types of asphalt mixes include hot, warm, and cold. However, these types can be specifically manufactured as distinct mixtures to more perfectly meet the needs of a project.

Whether you’re planning on resurfacing your driveway or you work in construction and you’re taking on a much larger project, it’s important to be aware of the different types of asphalt that you may come across. That way, you can determine which product is best for your specific needs.

Asphalt technically refers to a sticky, black, highly viscous liquid or semi-solid form of petroleum. Though, since roughly 70% of the material is used in road construction, the term “asphalt” is often used to describe asphalt concrete. Asphalt concrete goes by many names, including asphalt, pavement, or blacktop in the United States, and rolled asphalt, tarmac, or bitumen macadam in the United Kingdom.

Though, all of these different terms refer to the same thing: A composite material commonly used for surfacing everything from roads and parking lots to airports and even dams. Asphalt serves as a sustainable paving solution that is made with a combination of aggregates, binder, and a filler.

In fact, asphalt is the most versatile, recycled, and reused pavement material out there. It is used on roughly 94% of the about 2.6 million roads across North America. Though, asphalt mixtures have been used as pavement since the beginning of the twentieth century.

Asphalt pavement is made by combining aggregate, such as crushed rocks, gravel, or sand, along with asphalt cement as the black sticky adhesive that binds everything together. The asphalt itself serves as a binder for the mineral aggregate, which is then laid in layers and compacted. Asphalt pavement is typically composed of about 95% aggregate and 5% asphalt.

In the lower levels of the pavement layer, the aggregate particles are larger and less angular, while the surface levels feature particles that are smaller and more angular. Oftentimes, very fine aggregate particles referred to as “fines” are added into the mixture to extend the life of the pavement.

Asphalt pavement is usually created at a plant, where all ingredients are strictly measured to match the project type and climate of the site. The asphalt cement is thinned so that it can be combined with aggregate. There are several methods for thinning the asphalt, with heating being the most common.

The aggregate has to be cleaned, dried, and heated and when both the aggregate and asphalt reach the proper temperature, they are combined in a mixing machine – either a drum or pugmill.

Of all the different types of asphalt out there, hot mix asphalt is currently the most common form used for roads and pavements. It is a flexible mixture of both fine and coarse aggregate and an asphalt binder, resulting in a pavement that is durable, highly weather-resistant, and easy to apply.

This asphalt mix is created by heating the asphalt binder to lower its viscosity, and also drying the aggregate to eliminate moisture prior to mixing. The mixing process is usually performed with the aggregate at approximately 300 degrees Fahrenheit for virgin asphalt, around 330 degrees Fahrenheit for polymer modified asphalt, and 200 degrees Fahrenheit for asphalt cement.

Both the paving and compaction must be done with the asphalt is incredibly hot, so that it stays malleable enough to extend across the grade. Although it’s relatively easy to work with while hot, it cools down fast. Therefore, professional expertise is often required when applying hot mix asphalt. When dried, the mixture is hard as rock.

There are several different types of hot mix asphalt pavement, including:

Warm mix asphalt is made similarly to hot-mix asphalt, except at lower temperatures. In fact, it is created, mixed, and applied at temperatures about 50 to 100 degrees cooler. Reducing the temperature comes with a number of advantages, including a reduction in fuel consumption and a decrease in greenhouse gases during both the manufacturing and mixing processes. This makes it safer for the environment and more cost-effective.

Other benefits of warm mix asphalt include an increased paving season, enhanced production, improved long-term durability, and the capability to include reclaimed asphalt pavement (RAP). It can also be transported for longer distances without compromising quality and installed more effectively as it is somewhat easier and safer to apply.

Cold mix asphalt is produced by emulsifying the asphalt in water using emulsifying agent, prior to mixing it with the aggregate. When in this emulsified state, the asphalt has a lower viscosity and the mixture is much easier to use and compact. After the water evaporates, the emulsion breaks and the cold mix will, ultimately, take on the properties of hot mix asphalt pavement.

This type of asphalt is usually reserved for smaller-scale projects, such as patching jobs, and repairing potholes on rural roads. As the mix is not permanent, it is not recommended for use on heavy-traffic surfaces. Though, the two main advantages of cold mix asphalt are that it can be mixed on site with just soap and water, and can be applied in the winter time.

It comes in handy when repairs on needed on roads outside of paving season and/or if there isn’t a hot mix plant nearby. When applied and maintained properly, cold mix asphalt will last about a year.

Porous asphalt is typically used for paving parking lots as it limits standing water after heavy rainfall. As such, it is ideal for rainy areas of the world. When water collects on the surface of asphalt, it can cause damage, including potholes, which can prove dangerous for pedestrians and vehicles.

Though, porous asphalt resists pot holes and other damage by providing somewhere for standing water to go. To apply, a layer of porous asphalt is installed over a reservoir of open-graded stone. Then, when it rains, the water goes through the pavement and into the bed of stone, eventually permeating the soil underneath. If appropriately maintained, porous asphalt can last 20 years or more.

As the name suggests, quiet pavement is a form of asphalt that helps reduce traffic noise. By paving an especially noisy road with stone-matrix asphalt or open-grade friction, noise levels can be reduced by up to seven decibels.

Both open-graded and porous asphalt are commonly used as quiet pavement mixtures since they help to disperse the sound energy created by tires contacting the surface of the asphalt. Asphalt mixtures that are finely graded can also substantially reduce noise as they help to minimize the contact between tire and pavement.

Perpetual pavement combines several durable layers to yield a surface that is smooth, safe, and long-lasting. This is a style of paving that begins with applying a strong, flexible, and crack-resistant base layer. Then, the layer in the middle helps provide structural integrity and the top layer forms a rut-resistant surface that is responsible for the asphalt’s durability.

When perpetual pavement is consistently maintained and restored as needed, it can last at least 50 years.

Knowing which type of asphalt should be used for a specific project could mean the difference between the success and failure of your entire endeavor. By understanding all the types of asphalt, their specific uses, and their benefits, you should not be able to determine which is best for your property.

Though, regardless of which type of asphalt may be ideal for your situation, it is highly recommended that you work with a professional paving contractor. That way, you can ensure that you are getting the most out of your asphalt driveway, walkway, or parking lot.