Asphalt is the pavement of choice for roads in North America: it covers over 90% of our streets. Asphalt is quick to pave, easy to maintain, and highly versatile. It can even be recycled using portable plants for increased cost savings on future paving projects! Let’s dig into how this recycling process works and the portable plants that make it happen.
What Is Asphalt?
Before we dive into the recycling process, there is something we need to clear up. The term “asphalt” is often used ambiguously, similar to the way many people use the term “cement” when they really mean concrete.
Technically speaking, asphalt is a sticky, black, and highly viscous liquid or semi-solid form of petroleum. This liquid is the heaviest part of petroleum crude oil. It’s the material left over after all the other petroleum-based products, like gasoline, are distilled off. Mixing asphalt with aggregate turns it into asphalt concrete, the material used to pave our roads.
People use the term asphalt to identify both the liquid and the concrete mixture. To avoid any confusion here, we will be using both the terms “liquid asphalt” and “asphalt concrete” to properly identify the relevant materials.
How Is Asphalt Recycled?
There are a number of ways through which asphalt can be recycled, the most common being a hot mix asphalt (HMA) recycling process.
The first step in the process is ripping up and crushing old roads or asphalt concrete material. This new aggregate product is then screened for sizing. This step is crucial as the amount of material below ¼” is where most of the liquid asphalt can be recovered. Effective crushing and screening of fine asphalt material can double the amount of liquid asphalt recovery from 5 to 10%.
The recovered asphalt material is then mixed with new stone and fresh liquid asphalt to make new asphalt concrete for paving. Up to 50% of recycled asphalt material can be used in this mixture.
The recycled asphalt concrete that isn’t used for making new asphalt concrete can be repurposed for use as a road base or creating well-draining gravel parking lots, access roads, and driveways. This is similar to how recycled concrete can be used.
At Carminex, we’ve built portable impactor plants to crush and screen asphalt concrete on-site to eliminate expensive transportation costs. These plants have quick set-up and tear-down times to allow frequent movement between yards, and function as a complete plant on a single road portable chassis.
What Are The Benefits Of Recycling Asphalt?
The major benefits of recycling asphalt are the cost savings and environmental advantages. Recycled asphalt is cheaper to produce, and more readily available versus new asphalt mixtures.
In places like Ontario, the cost savings come from reusing the liquid asphalt since aggregate is readily available. In other areas like the southern US, the cost savings are driven by reusing the asphalt stones since aggregate material isn’t locally available and transport costs for new aggregate are very high.
Proper crushing and screening are critical to producing valuable recycled asphalt material. That’s why we only carry the best Sepro aggregate equipment along with quality Hewitt Robins™ parts. We also have experience building a wide variety of portable plants to deliver excellent cost-saving solutions to our customers. To find out how we can help with your next aggregate recycling project, give our experts a call at +1.450.922.0900.