Asphalt is one of the most often recycled materials globally, and the roads you are traveling on have likely been resurfaced many times using recycled asphalt. Using recycled asphalt makes the cost of laying an asphalt driveway at your home cost significantly less than using freshly made hot asphalt driveways.
As is the case with freshly laid asphalt, recycled asphalt needs to be repaired and resealed every two to three years. Recycled asphalt is an excellent option in areas with high rainfall, snowfall, and temperature extremes. If well installed and maintained, it can last for more than ten years.
The recycling of old asphalt does not detract from the quality and durability of the driveway when correctly milled and reinstalled. Let’s look at why recycled asphalt is as good as newly laid asphalt.
How Is Asphalt Made And Why Is It Recyclable?
Asphalt is the residue of the process of refining crude oil. This blackish-brown sticky substance is also known as bitumen and can be mixed with stone aggregate, fillers, and stabilizers to yield asphalt or Tarmacadam (Tarmac). Asphalt is ideal for laying roadway surfaces.
The asphalt is heated up to be pliable and workable when laying fresh or recycled roadways. The material can be shaped and compacted on top of a well-prepared surface to provide an ideal surface to provide vehicle tires with optimal grip and not generate road noise.
The weathering effects cause the asphalt to lose the organic volatiles and cause it to become brittle and crack. If the surface is not repaired and resealed with regular maintenance, the top layer of aggregate will become loose and cause the roadway to become slippery.
Special machines are then required to strip off the asphalt top layer to a depth where the substructure is stable. The stripped-off asphalt can be milled to a fine aggregate and mixed with fresh hot bitumen before being laid and compacted again. The laying of recycled asphalt is significantly less expensive than laying fresh asphalt.
How Is Recycled Asphalt Hardened?
Once the old brittle asphalt has been stripped off-road surface and milled to a consistent size, it is mixed with hot bitumen and other recycled filler materials such as rubber to form a freshly mixed batch of asphalt. The surface preparation of where the asphalt is to be laid is critically important.
If the sub-surface is not stable and well compacted, putting on a fresh layer of asphalt is a waste of time. The warm asphalt is laid down to fill the roadway’s surface and is compacted using a combination of light and heavy rollers. Once the asphalt has been shaped and compacted, a dusting of Calcium Carbonate powder will help to harden the surface.
The Calcium Carbonate powder reacts with the bitumen in the asphalt due to a spontaneous (exothermic) reaction, causing the bitumen to heat up and fill in all the micro-fissures and voids in the asphalt. When the asphalt cools down, it becomes a hard and compact structure.
On very hot days, the asphalt will absorb the sun’s heat and become soft and pliable. Heavy trucks will cause the asphalt surface to distort and form ruts and unevenness of the asphalt surface. The asphalt is mixed with stabilizer fillers to minimize the effect of heat distortion.
Water will penetrate the asphalt into every void or fissure and freeze and expand in the cold, wet, and snowy weather. The effect is that the cold, brittle asphalt will develop cracks and start to break up under heavy traffic. Maintenance crews sprinkle coarse salt onto the asphalt to suppress the freezing point of water and prevent it from freezing and forming black ice.
Required Maintenance To Maximize The Lifespan Of Recycled Asphalt
Laying recycled asphalt on the driveway on your property is a far more cost-effective way of surfacing your roadway when compared to paving or laying fresh asphalt. The surface preparation is critical to make the installed recycled asphalt last for as long as possible.
Make use of a professional installer to lay the recycled asphalt for you. You can do some of the maintenance yourself to prolong the life of the roadway. Using a seed sprinkler, sprinkling of Calcium Carbonate powder to allow the surface to harden. Fill the seed sprinkler with powder and push the sprinkler over the tarred surface, ensuring even coverage over the entire surface.
How Often Should A Recycled Asphalt Surface Be Resealed?
A recycled asphalt surface should be resealed every two to three years, and all cracks must be opened up and repaired with freshly mixed asphalt and compacted. Remove all weeds growing into the surface to prevent their root system from damaging the substructure of the tarmac.
The preparation of the sub-surface and the quality of the installation of the recycled asphalt will be the determining factor as to how long the interval between subsequent resealing. If the soil layers beneath the driveway have a high clay content, additional coarse aggregate must be compacted to stabilize the sub-surface layer.
What Are The Pros and Cons Of Using Recycled Asphalt
Advantages of Recycled Asphalt
- Recycled asphalt is significantly more affordable when compared to virgin asphalt. The cost of preparing virgin asphalt is significantly more than recycled asphalt – up to 5 times as much, in-fact. Virgin asphalt requires aggregate to be purchased from a quarry and transport costs to the point of use. The preparation of virgin asphalt also requires more oil, bitumen, labor, fillers, and stabilizers.
- Recycled asphalt is friendly to the environment. Asphalt is the most recycled material on the planet, and it can be recycled for an indefinite number of cycles. The asphalt can be stripped off the road surface, milled to achieve a uniform grain size mixed on-site, and be laid after mixing with bitumen and other compounds without the need for long-distance transport.
- The bonding qualities of recycled asphalt are good as it already contains a high level of tar. The mixture with recycled asphalt with additional stone aggregate and bitumen produces a better bonding compound that requires less oil and heat to become pliable. The improved bonding and pliability of recycled asphalt are likely to result in a better material to work with than virgin asphalt.
- Recycled asphalt is ideal for roadways with a high level of rainfall and snowfall. As the recycled asphalt is more coarse, it will allow water to pass through the surface and be less prone to cracking due to expansion and contraction due to temperature extremes.
- A recycled asphalt driveway is authentically more pleasing than a gravel roadway, and costs less than twenty percent of what a virgin asphalt driveway will cost. Although the recycled asphalt driveway will require maintenance and resealing to maintain its optimal appearance and function, the cost will be similar to that of a virgin asphalt surface.
Disadvantages of Recycled Asphalt
The cons of recycled asphalt are not that serious, and easily justified due to the cost differential.
- The color of recycled asphalt is not as deep black as virgin asphalt. For most homeowners, this color difference is not a significant issue. If you want the deep black appearance of freshly laid virgin asphalt, be prepared to pay a significant premium.
- The quality of recycled asphalt may vary greater than virgin mixed asphalt. Ensure to assess the quality of the recycled asphalt and correct the level of expectation of what the finished surface will look like. Use a reputable contractor with good references who can provide a quality warranty.
- You are making a compromise when installing recycled asphalt, but it is a very slight one. Do not attempt laying recycled asphalt yourself. It is not a DIY task. The job requires specialized equipment and mixing in the bitumen and other hardening compounds. Laying and compacting is also a specialized skill that is worth paying for.
Conclusion
As far as recycled asphalt is concerned, it is a fallacy to say that recycled asphalt will not last as long as freshly mixed virgin asphalt. Asphalt consists of uniformly sized aggregate stones mixed with hot bitumen and some hardening compounds. When a roadway surface is lifted and reprocessed, the resultant material is in no way inferior.
You can select the option of having recycled asphalt installed at your property with the confidence that it will look good and last for many years. As is the case with virgin asphalt, recycled asphalt needs to be resealed and maintained every two to three years to get the maximum life expectancy.