Every year, local highway departments throughout the USA replace an estimated 100.1 million tons of asphalt.
80% of removed asphalt is recycled for roadbeds, shoulders and embankments, saving state and local transportation departments millions of dollars and keeping 80.3 million tons of undegradable asphalt from our nation’s landfills.
In this article, we’ll explain how you can get on the savings and feel good about your small contribution to the environment.
What exactly is a recycled asphalt driveway?
A recycled asphalt driveway is a driveway paved with removed paving materials comprised primarily of asphalt and aggregates. The crushed and milled asphalt is often further blended with a small percentage of virgin asphalt to aid binding.
The recycled asphalt comes primarily from our nation’s roads and highways but may also come from old commercial parking lots or airport runways.
The asphalt may be removed either by milling in place using specialized equipment or, more commonly, full-depth removal.
Milling in place uses specialized equipment that removes the existing asphalt in layers of about 2 inches. In-place milling is most common in situations where the recycled asphalt is intended for reuse on-site.
If you are redoing an existing driveway, milling in place is a possibility. Still, most often, you’ll receive recycled asphalt that’s been removed full-depth from another location. Full-depth removal is done using a bulldozer equipped with a rhino horn and pneumatic breakers. Milling companies load the removed asphalt into dump trucks and deliver it to nearby milling plants.
The milling plant crushed the asphalt into smaller pieces and sifted to remove the fine particles inappropriate for recycling.
The milled asphalt varies in quality and composition depending on the source material. It may or may not need to be blended with additives before reuse.
We’ll go into more depth about the process later in this article. In short, the milled asphalt is spread on a driveway and then pressed using a steam roller or hand-roller. The semi-soft bitumen in the asphalt acts as a binder.
The loose asphalt aggregate compresses into a semi-solid surface that looks similar to the original asphalt and grows harder over time.
Advantages of recycled asphalt
If you decide to go with a recycled asphalt driveway, you’ll definitely get green bragging rights over your neighbors.
Neither concrete nor asphalt are sustainable paving choices. New materials require significant energy use, mining and or drilling.
On the other hand, recycling asphalt uses only the energy burned by the equipment required to remove it and the milling process.
You are also helping prevent old asphalt from being dumped in a landfill where it will not degrade for centuries.
You’ll also save money with a recycled asphalt driveway. A recycled driveway’s labor cost is similar to a virgin asphalt driveway, but the materials costs are roughly 1/4.
Depending on the size of your driveway, this may result in hundreds or even thousands of dollars in savings.
Recycled asphalt is usually sold by the ton. One ton covers about 80 square feet of driveway. The cost of recycled asphalt can vary enormously depending on your geographic area and ranges anywhere from $7/ton to $60/ton.
The average driveway is about 600 square feet and would need a little of 7 tons of recycled asphalt.
Once your recycled asphalt driveway is in place, you’ll have almost no maintenance. Unlike gravel or oil and stone, the asphalt aggregate does not come loose or wash away. You may want to power spray your driveway annually, and that’s about it for maintenance of a recycled asphalt driveway.
Some homeowners may opt to seal their recycled asphalt driveway, in which case the sealant will need replacing every 2 years.
If you live in an area with substantial rainfall or drainage problems, recycled asphalt is a smart choice.
Unlike asphalt or concrete, recycled asphalt is porous. You won’t have to deal with puddles or runoff issues.
You also won’t need to connect your driveway drains to the local sewer system, as is often the case with other paving options.
Gets Stronger Over Time
When you first lay down your new recycled asphalt driveway, you may notice it feels a bit soft underfoot. You may also have some loose asphalt kick up on your car’s undercarriage and fender wells.
This is a temporary condition. Each time you use your driveway, your car’s weight further compacts the recycled asphalt, making the asphalt just a little bit stronger each time.
Eventually, the material reaches maximum compaction, and you will have a hard, long-lasting driveway surface.
Recycled asphalt also results in one of the most durable driveway surfaces. A good quality recycled asphalt driveway will last about 20 – 30 years with minimal maintenance or hassles of any kind.
Compare that to gravel (and equally low-maintenance option) with a predicted life of just 10 years.
Only concrete driveways last longer but with considerably more annual maintenance.
When you finally do need to replace your Recycled asphalt driveway, you can recycle it again!
Disadvantages of recycled asphalt
Before you call a paving contractor, there are some downsides of recycled asphalt driveways you should consider.
If you’ve ever seen an old country backroad paved with recycled asphalt, then you understand the appearance of recycled asphalt.
Recycled asphalt driveways look similar to regular black asphalt but are rough and a bit patchy looking. This can give a more industrial look to a driveway than some homeowners would prefer while missing out on the “sleek” look of virgin asphalt.
Over time, recycled asphalt fades to a nondescript grey color, which is often not an excellent match for many home exteriors and landscaping choices. While it remains just as usable, it may not be as appealing as when it was first completed.
Cracks and Potholes
You must take great care in selecting your contractor when doing a recycled asphalt driveway.
While recycled asphalt has the advantage of becoming harder with time, increased hardness comes with a price. As the asphalt hardens, it becomes more brittle.
If there are any problems with the underlying soil or gravel, those problems are likely to present as cracks or potholes.
Such cracks and potholes are relatively easy to fix. But if you’ve ever noticed the seemly endless presence of road crews repairing potholes on roads made of recycled asphalt, you may already understand that these cracks and potholes do not stay fixed for long.
Consequently, once cracks and potholes appear, you will likely face annual or bi-annual maintenance to keep them from reappearing.
This is caused by traffic consistently on the same line, as is common in a residential driveway.
The problem of rutting is especially common in hot climates.
In contrast, they suffer from a completely different problem in cold climes.
Recycled asphalt driveways are porous. Without excellent drainage, rain and snowmelt can become trapped between the driveway surface and the bed.
When this water freezes and expands, it can lift large sections of the recycled asphalt. This process is called heaving.
Widespread heaving will destroy a recycled asphalt driveway requiring a complete replacement.
We noted earlier that recycled asphalt has a favorable environmental impact rating compared to other surfacing options.
This favorable assessment is based on the impact of sourcing the raw materials, carbon footprint during installation and the Albedo effect of reflected sunlight.
However, there are environmental downsides of recycled asphalt driveways.
Remember, your recycled asphalt can come from just about anywhere. You won’t know where it came from. Most asphalt mills pay no attention to this at all, and there are unlikely to be records of the source location. Materials from various source locations are mixed freely.
This means you could be potentially importing polluted materials and contaminants, including pesticides, heavy metals, plastics and more.
Recycled asphalt leeches into the underlying bed, and these contaminants can migrate to surrounding landscaping and lawns.
Furthermore, the relatively loose structure of recycled asphalt can, especially in warm climates, result in driveway materials adhering to shoes and tires. This foreign material is then tracked in the house and garage areas.
The bitumen in recycled asphalt driveways can contain high concentrations of polycyclic aromatic hydrocarbons (PAHs). PAHs are considered a targeted pollutant by the US Environmental Protection Agency.
The PAHs in recycled asphalt driveways are easily blown off or washed off the surface. This wash-off contributes to the pollution of nearby groundwaters, and the blow-off contributes to air pollution.
Difficult To Replace
Eventually, your new recycled asphalt driveway will need replacing. With luck and a quality installation, that day may be 20 -30 years in the future.
On the other hand, if you experience any of the problems mentioned above, the day of reckoning could be much sooner.
Recycled asphalt cannot be paved over using any technology we currently have. This means you are looking at a 100% removal.
That removal process can be messy and release even more potentially hazardous PAHs into your home and the surrounding environment.
On the plus side, your removed asphalt will be eligible for milling and recycled yet again.
What to expect when installing a recycled asphalt driveway?
- Check your local regulations and community bylaws.
Many communities in the United States do not allow either asphalt or recycled asphalt driveways. Check with your local regulators or read your homeowner’s association’s bylaws before proceeding further down this path.
Remember, just because your neighbor is doing it doesn’t mean it’s regulatorily approved. Do your homework.
- Find a qualified contractor.
Theoretically, a recycled asphalt driveway can be a DIY project, but most homeowners opt to hire a pro.
Look for a local contractor who specializes in recycled asphalt driveways or, at a minimum, has a substantial portfolio of work to show you.
Be sure to ask for references from other projects. Again, do your homework and actually talk to the references. If possible, visit the project and see it for yourself.
Talk to the contractor about where they get the recycled asphalt. Are they milling themselves, or are they working with a largescale mill? Large scale asphalt recyclers will have better quality control and produce a more consistent product.
Small-scale milling can be hit or miss.
Of course, price is always a consideration. Be sure to get multiple quotations to ensure you are being treated fairly. Beware of any bid significantly less expensive than the other proposals you receive. A low-ball bid is probably cutting corners or is a sign of inexperience.
- Prepare the Bed
Your contractor will spend anywhere from two days to a week preparing your driveway. They will grade the soil and design drainage.
They will then use a roller drum to compact the soil, followed by a loose gravel layer.
- Spread the Asphalt Millings
Dump trucks will deliver the asphalt millings to your driveway. Your contractor will spread the milling using a bulldozer or (for smaller projects) by hand.
Expect about a 4-inch layer of milled asphalt. Be sure to inspect yourself to ensure the asphalt is spread evenly, adequately sloped for drainage and precisely edged to accommodate your landscaping.
Your contractor will initially compact the recycled asphalt using a 25-ton pneumatic-tired roller. This should be followed by a second compacting using a 12-ton or larger vibrating drum roller.
The drums will be kept wet to avoid sticking.
- Cure & Seal
Technically, your new drive is ready to use right away; however, in the interest of your car’s paint job. You should wait 1 to 3 days to let the new asphalt cure.
Your contractor may recommend a layer of sealant after curing, depending on local conditions.
For the environmentally-conscious homeowner, a recycled asphalt driveway may be a perfect choice.
- It is greener than most paving options, including asphalt and concrete
- One of the least expensive paving options
- One of the most durable options.
However, they do come with some tradeoffs. The most obvious is they may not be the most aesthetic choice.
As always, do your homework. Your choice of driveway paving is a decision you will live with for literally decades, and you will see the results every time you drive your car up or down the drive!