Asphalt is the most recycled material in the world, measured by weight — approximately 75 million tons per year (or about twice as much as paper, glass, aluminum, and plastics combined.)
Despite this, there is a tremendous oversupply of recycled asphalt that is removed from roads, parking lots, and driveways when it’s repaired or replaced. Current technology allows a maximum of about 20% recycled asphalt to go back into new hot asphalt mix (pilot projects are trying to push it to 40%). So what happens with the other 80%?
We have been working with our suppliers to think of some creative ideas, both from a functional perspective and from an environmentally-conscious perspective, of how we can find end-of-life uses for this material that are not currently commonplace.
The potential applications for recycled asphalt to add value are vast. Any area that’s currently dirt or gravel that’s either a mud pit or full of potholes is a candidate for recycled asphalt — dirt parking lots, private roads or driveways, alleys, or pathways. It also greatly reduces the consumption of scarce resources such as fuel, equipment, hauling, and labor when compared with producing virgin materials for the same end-use applications.
There are sometimes misconceptions about what exactly recycled asphalt is. It’s appropriate to think of it more like gravel than like traditional asphalt. It’s a soft surface, not a hard surface. The excavated materials are ground up and reprocessed so there’s an appropriate mixture of large aggregates and small aggregates (or fines). This helps the material to bind together better. The presence of liquid asphalt from the old pavement (usually about 4-6%) also provides an element of cohesiveness that gravel is not going to have, especially when it’s applied in the hotter months and the oils can soften up a little, and then re-harden.
Fortunately, recycled asphalt can be applied using the same trucks, tools, equipment, and employees as traditional asphalt, so large quantities can be placed efficiently. Moreover, the material is much cheaper than virgin aggregates, so the end user can get a nice product very inexpensively.
An interesting side note is that placing recycled asphalt over large surface areas actually allows nature to continue running it’s course. Over time, tiny microbes will begin to eat away at the liquid asphalt materials and return it naturally back into the environment.
According to the Asphalt Institute, “the results of leachability tests show very low levels of leachable compounds, well below any current Environmental Protection Agency guidelines.” In fact, Washington and Oregon have more than 35 fish hatcheries with ponds that contain asphalt linings — an asphalt surface, plus an asphalt emulsion sealer. What’s more, many of the world’s water reservoirs built in the last century contain asphalt surfaces or linings.
The possibilities of recycled asphalt are also good for our company and our employees. We’re not bashful to announce that. As a seasonal business, we’re always looking for ways to extend our season as long as possible. This material can be placed in almost any kind of weather, as long as it’s not snowing. Our employees and their families certainly appreciate how this allows them to get solid paychecks throughout the winter.
Rainier Asphalt & Concrete strives to be an industry leader in trying to find creative ways to manage this product at the end of it’s life.