Recycled asphalt is old asphalt paving that has been removed, crushed, and mixed with new aggregates. The mixture is then reused for highway construction, residential driveways and parking lots. It is 100% renewable and durable with long life span.
Over the years, recycled asphalt has cemented its identity as the United States most recycled material. It has become the preferred choice for highway construction, road rehabilitation, and residential construction. Boasting high quality and saving about 59 cubic yards of landfill space, it’s no wonder why it is the country’s favorite. Renewed asphalt is a highly beneficial material. Its benefits span from cost savings to environmental friendly, better quality, and waste reduction.
Are you unfamiliar with asphalt recycling and heard diverse rumours? Or do you want to know if RAP is better than virgin asphalt? This expert guides covers all the benefits of recycled asphalt, the cost, the pros and cons. Here is everything you need to know about asphalt recycling.
What Is Recycled Asphalt?
Recycled Asphalt is reused asphalt paving, grounded, and reprocessed for highway construction, like recycled cold and hot mix asphalt pavements. It is also used for residential driveways and parking lots. Asphalt pavement recycling makes asphalt the most recycled material in the United States till date.
Pros and Cons of Recycled Asphalt
Renewing asphalt has great benefits, but like most things, it also has its disadvantages. Luckily, the benefits outweighs the risks. Let’s take a look at both sides
Pros of Recycled Asphalt
There are many benefits of using recycled asphalt for your next hardscape project, some of them include:
Cost Effectiveness
Asphalt pavement recycling is very cost-effective.The National Asphalt Paving Association says nearly $2 billion in taxpayers’ dollars are saved annually by using recycled asphalt pavement in construction. This figure was achievable because recycling requires less transportation and reduces the cost of production materials. The recycling process is not only cost-effective for America’s economy, it is also affordable for individuals who want to use asphalt for their driveway.
Environmental Benefits
Asphalt renewal contributes immensely toward making the environment friendlier. Asphalt itself is non-degradable, and dumping it in landfills is not eco-friendly. But you can reuse asphalt several times thanks to recycling. According to the National Asphalt Pavement Association, 99% of asphalt reclaimed pavement is used in new pavement. Also, in 2019, 97 million tons of RAP and 1 million tons of RAS were collected for reuse, saving nearly 60 million cubic yards of landfill space.
Another environmental benefit is that recycling old asphalt decreases material waste and reduces the use of non-renewable resources, like gravel and sand, used in production. Also, the diminished use of new oil automatically reduces carbon footprint during the mining and processing stages.
High-Quality Material
Recycled asphalt is commonly called high-quality asphalt. Additives like Nano-lime, Nano-Alumina, and Nano-clay are used to improve the mechanical properties of asphalt, which makes it win against traditional asphalt in areas, like durability, stiffness, and crack resistance.
It Reduces Waste in Other Industries
The benefits of recycling asphalt also extend to other industries since their waste materials are also beneficial to asphalt reprocessing. Materials from glass, plastic, asphalt shingles, tire rubber, slags, and foundry sand that would have landed in landfill are salvaged as adjunct for recycled asphalt. Thereby reducing waste and combating climate change.
Good Bonding Qualities
Another advantage recycled asphalt has over virgin asphalt is its bonding quality. After recycling, the asphalt material still has tar, allowing it to bond better when wet and compacted. On the other hand, new asphalt is more of a loose-filled aggregate, it needs extra additive for bonding.
It Supports Percolation
Reclaimed asphalt allows water to pass through it more easily. It prevents snow piles, flooding, and water pools in your parking lot. If you live in an area with heavy rainfall or snow, renewed asphalt is your best bet.
Cons of Recycled Asphalt
While recycling asphalt offers many exciting advantages,it also has its disadvantages, which includes:
Varying Quality
The major problem with using recycled asphalt is quality. The quality of reusable asphalt may vary, depending on how and where it was processed. Other factors that can affect the quality include the number of times the pavement has been resurfaced, the quantity of debris that mixed with the asphalt while it was stored, and the recycler’s reputation.
Durability
Reused asphalt material is more durable than virgin asphalt. But low-quality ones may experience early cracking, rutting, and ineffective bonding, which means your recycled asphalt driveway or pavement won’t last long.
Difference in Color
Recycled asphalt has a different look and color from the deep black conventional asphalt. Some people find this more attractive than the original look, but some homeowners think otherwise. Generally speaking, this is a matter of preference. So, this isn’t the right option if you prefer the rich black of virgin asphalt.
The Possibility of Contamination
When reusing asphalt, it can get contaminated. Poor maintenance can cause your paving to degrade over time. This is because prolong exposure to oil residues, heavy traffic and chemicals affect the bonding materials in your asphalt driveway, thereby reducing the quality and contaminating your asphalt with debris and dirts.
How To Recycle Asphalt in 5 Steps
There are five primary steps involved in recycling pavement asphalt. In this section, we will give a detailed description of each step without leaving any stone unturn.
1. Asphalt Milling
Asphalt milling is simply the process of removing the top surface of an existing asphalt pavement. This is done by a milling machine before reconstructing the pavement. The milling machine has a teeth that digs up the pavement about two to four inches deep before crushing it.
2. Crushing Of Asphalt Pavement
Next, the material will pass through the grinding unit that crushes it. The miller will then sieve the crushed asphalt and move it to an outlet conveyor attached to the machine. The final result is a glossy recycled asphalt pavement.
3. Mixing RAP with New Materials
For RAP to be reusable, it has to be mixed with new materials. The materials include, virgin aggregate, virgin asphalt binder, and, sometimes, a recycling agent This gives RAP the durability to compete with traditional asphalt.
4. Quality Check
A quality check is necessary to ensure the RAP meets the required quality before use. Usually, reusable asphalt ought to meet or surpass the quality of virgin asphalt. If the retrieved asphalt doesn’t pass the quality check, it won’t produce the desired high-quality, durable pavement. Neither will it save cost. The quality check includes checking the RAP source, particle sizes, field moisture content, moisture damage, and rotting susceptibility.
5. Application of Recycled Asphalt Pavement
Of course, once the recycled asphalt has been certified for use, the next step is applying it. It can be used in various applications, including highway roads, road rehabilitation, and residential pavings. Typically, you will lay down the reusable asphalt and tamp it down. To finish up, use a steam roller to harden the layer, then apply a seal coat.
The Best Techniques to Recycle Asphalt
There are several techniques for recycling asphalt. Despite the method used, the end product is reusable asphalt. Below are the best techniques to consider for asphalt recycling:
Cold Recycling
Cold recycling is a method of recycling asphalt that doesn’t involve using heat. There are two types:
- Cold in-place recycling (CIR)
- and cold central plant recycling (CCPR)
Hot Recycling
The hot recycling method uses RAP as an aggregate in hot mix asphalt. The reclaimed pavement is mixed with new materials to produce hot-mix asphalt. There are also two methods of hot recycling:
- Recycled hot mix (RHM)
- Hot in-place recycling (HIR)
In-Situ Recycling
In-situ recycling is an on-site recycling process. That is, the asphalt recycling will be done on the existing asphalt pavement site before laying down the recycled asphalt. This method eliminates the need for transporting the existing asphalt and reduces cost. This method works for both hot and cold mix asphalt.
Cold in-place recycling (CIR) involves removing the existing asphalt surface and mixing it with a recycling agent or binder. Sometimes, they add an aggregate to correct deficiencies in the old asphalt material.
On the other hand, hot in-place recycling (HIR) involves softening the asphalt pavement surface with heat and scarification or mechanical removal of the surface. Next, the recycled asphalt material will be mixed with other materials, like binder, and then they will lay the pavement surface.
Milling Recycling
In the milling recycling process, the existing pavement must be milled first using a milling machine. It’s at the milling stage they retrieve the old asphalt. The milled material gets mixed with a binder and sometimes aggregates using the cold in-place method. And, of course, the last step is to lay it back on the road for construction.
Foam Bitumen Recycling
Cold recycling can be done using foamed bitumen as a binder. Foamed bitumen is obtained by mixing hot bitumen with water. The benefit of using foamed bitumen is that the asphalt material can be fully recycled. It also reduces the cost of binder as asphalt pavement recycled with foamed bitumen needs less binder and water than other cold mixing methods. Bitumen can easily be obtained and used immediately without further processing, saving time during construction.
The Federal Highway Administration Policy On Recycled Asphalt
The Federal Highway Administration (FHWA) support the use of recycled asphalt in the construction of highways. They know that recycling preserves the natural environment, reduces waste, and is cost-effective. To show their support, the FHWA set goals towards encouraging asphalt pavement recycling. Their objectives includes:
- Encouraging the use of recycled material in the construction of highways to the maximum economical and practical extent possible with equal or improved performance;
- Promoting the use of Reclaimed Asphalt Pavement (RAP) because the utilization of RAP can have the greatest economical, environmental, and engineering impact on pavement recycling.
Where To Buy Recycled Asphalt
You can’t buy a recycled asphalt from any company because there is low-quality asphalt out there. If you are in search of a reputable company to buy from, we are here to ease you of your stress. Our directory contains the contact of top paving contractors in the U.S. You only need to run through the list to find the one closest to you. Below are some quick tips to help you find the right contractor:
- Ask your family and friends for recommendations
- Read online reviews by previous clients
- Check their website to learn more about them and go through the gallery to view their past projects,
- And lastly, consult with the company if you have any questions about their services
FAQs About Recycled Asphalt
Here are the top three FAQs every homeowner ask before buying recycled asphalt.
What is the Difference between Asphalt and Recycled Asphalt?
The simple difference between asphalt and recycled asphalt is in the word “recycled”. Asphalt is a mixture of mineral aggregates bound together by an asphalt liquid. On the other hand, RAP is an asphalt material recycled from old asphalt and repurposed for reuse.
Is Recycled Asphalt Environmentally Friendly?
Reclaimed asphalt is environmentally friendly. It salvages non-biodegradable materials into new asphalt, thereby reducing waste materials and greenhouse gases. The recycling process also saves natural resource and reduces the energy needed to produce virgin asphalt. Reclaimed asphalt pavement can survive surface cracks, minimize rutting and improve sustainability. It protects our environment and reduces America’s carbon footprint.
Is Asphalt Better for the Environment than Concrete?
Concrete is a more sustainable and eco-friendly option compared to asphalt. It is lighter and has a high albedo meaning that it absorbs less heat, although it requires more energy for production. Asphalt on the other hand is black and generates more heat. It has a reflective coating that contain energy intensive polymer which release harmful gases during processing. But with recycled asphalt the environmental benefits of asphalt paving overshadows that of concrete which is not often recycled.
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