Last Updated on February 22, 2022 by Grow with Bovees
What is Asphalt Milling?
Asphalt milling, also known as pavement milling, is the process by which old existing asphalt surfaces are milled and ground up into smaller chunks of asphalt.
This happens when old asphalt surfaces have reached the end of their life cycle, usually because of excessive cracking and damage or sometimes because the space is being repurposed.
Traditional asphalt is removed and crushed into what is known as RAP (recycled asphalt pavement), or asphalt millings, and you can use this inexpensive material to make your own asphalt millings driveway!
These millings are reused as recycled material and have many applications that are often cheaper and more environmentally friendly than traditional paving materials.
The asphalt milling process is relatively new to the industry and has been around since the 70’s to get rid of old asphalt.
In the following, we will be discussing possible benefits and drawbacks of using a mixture of milled asphalt and what makes asphalt millings popular for several different applications.
What Would You Use Asphalt Millings For?
Anything from filling some areas for concreting to building an asphalt millings driveway. With proper installation, this material can be a great and robust alternative for traditional crushed gravel materials and paved asphalt.
In addition to that, these recycled asphalt materials are usually more affordable and much better for the environment.
Recycled asphalt millings also have huge industrial applications, but we will be focusing more on why it is good for use in small projects such as asphalt milling driveways, for instance.
Is Milled Asphalt Better Than Gravel or Traditional Asphalt?
The biggest advantage of using milled asphalt as opposed to conventional gravel or your normal asphalt paver, is that it has been recycled and does not take up yards of landfill space.
It is eco-friendly and should be made use of as an alternative. Also, it is much more pleasant than jagged gravel. Apart from the environmental advantages, here are some other plus points:
Asphalt Millings Cost Benefits
Recycling is usually a lot cheaper than manufacturing new materials. As it is in this case, gravel is the more expensive option. Even fresh asphalt will be more expensive than milled asphalt.
Asphalt Durability
Recycled asphalt mixture holds up very well under most weather conditions, even heavy snow and rainfall are not a problem here. Upkeep against wear and tear is where milled asphalt trumps regular gravel.
Asphalt Maintenance
The time-consuming upkeep that surrounds any gravel road, is what makes them generally less desired. Resurfacing is constantly necessary and loose gravel can be a nightmare to keep well compacted.
Asphalt millings generally tend to bond stronger and produce much smaller amounts of dust, reducing the time you will need to spend washing your truck. Expensive maintenance is mitigated and the road surface is more pleasant and drivable.
Seasonality
Come hail or shine, heat or extreme cold, recycled asphalt can take it. If you live in a place where you experience cold winters with loads of snow and ice, an asphalt surface is much better.
It produces less formation of ice on the surface and also allows for snow to melt faster than on a gravel driveway or road.
What Is the Average Lifespan of Recycled Asphalt Pavement?
The lifespan of any material usually depends heavily on factors such as general maintenance, exposure to weather and the application of the material.
However, if all these conditions are regularly maintained and the material is properly installed and used for regular application and traffic, then a driveway or milled asphalt pavement should last just as long as fresh asphalt. Which is usually in the region of around 15 plus years.
Are Asphalt Millings Good for Driveways?
Milled asphalt driveways are becoming more popular than using gravel or fresh asphalt. The question is why is this preferable to regular asphalt?
Once this material has got a solid base and good compaction, preferably by a drum roller compactor, asphalt milling becomes very strong and robust. Along with it being cheaper and more environmentally beneficial, it is a fantastic option for use in the construction of driveways and home paving.
For streets and larger projects, this option is not as viable and the preferred method of hot mix asphalt is usually used. So, if you are planning on building a new driveway, head over to a local asphalt millings supplier or ask your contractor about this option.
How Do You Harden Asphalt Millings?
Fresh asphalt is usually applied using a hot asphalt mix that requires special equipment and production processes. This hot asphalt spread is then applied to a surface creating a fresh non-recycled asphalt road.
Millings, however, can be applied without the application of heat and with less complicated paving equipment and therefore provide a good alternative to regular paved asphalt.
Cold mixture asphalt millings are much more suitable for small home or business paving projects and are good for the carbon footprint. Generally, the millings are spread out at the proper thickness, compacted by a compactor roller, left to cure for 24 hours and then sealed with a specialized sealing liquid.
It is imperative to harden asphalt millings correctly. If hardening asphalt millings has not been done correctly, it may lead to damage later down the line.
If you are looking to redo your driveway, we suggest speaking to a milled asphalt contractor. However, if you wish to make it a DIY project, be sure to find out exactly how it is done.
Here Is a Basic Guideline on the Steps That Need To Be Followed:
Site Preparation
Preparing your ground is extremely important here. Installing a crushed stone sub base layer, and grading it to the proper standard, taking into account an appropriate gradient to ensure good water runoff and allowing for a stable base to be compacted is very important.
If you do not do this correctly, it may affect the quality and call for more frequent asphalt resurfacing or frequent patching, as your asphalt driveway will not be of sufficient quality.
Compacted Soil
Compacting your base soil is the next step. Your initial compaction will prepare the site for the application of even asphalt in layers that will be coming on later. Usually a hired 25-Ton pneumatic-tired roller will work great here. This double drum vibratory steel-wheeled roller offers great compaction, making your base stronger.
Inspect millings closely
When you are procuring your millings from your supplier, be sure to inspect them to make sure that the average recycled asphalt chunk is not bigger than about 2 inches in diameter. If there are bigger pieces in the load, they need to be crushed down into smaller pieces of asphalt.
Add emulsion
Emulsion is needed when the ground-up recycled asphalt is not the correct consistency, either because of a lack of fine material or otherwise. It is generally a combination of asphalt in water, the water droplets of asphalt that is extremely fine, helps the mixture to bond together correctly.
This is called combined emulsion. If this has not been accounted for, it may be a potential issue, so be sure to ask your recycled asphalt manufacturers about it when using asphalt millings for your paving project.
Distribute the Millings
You might have a tough time distributing the millings by hand, so we suggest using a bobcat or backhoe loader to do this work for you. Using a smooth edged rack bucket will make it easier to level and spread your asphalt product.
It is a lot faster and a lot less physically exhausting than shoveling asphalt millings until you have the desired level. Getting the mix level and even is very important as it may cause issues during surface compaction as your milled asphalt driveway will end up with hollow spots and inconsistent densities.
How Thick Should Asphalt Millings for a Driveway Be?
The thickness of your asphalt millings should be around 2 to 3 inches for driveways and for parking areas.
- Compact the millings
This usually works best with a roller compactor that has two heavy steel drums that make the compaction task fairly simple. Keeping the edges at about a 45 degrees gradient, will ensure good water runoff and will add curb appeal to the project.
- Wait 24 hours
Leave your asphalt milling road for a day, so that proper bonding can take place. Do not drive on it during this period of time.
- Seal
Speak to a certified asphalt specialist to find the correct sealant to use. Usually, a chip-seal mix is appropriate. The correct seal-coat and application process are also very important for the quality of your work.
- Rules to remember
There are a few rules and regulations surrounding asphalt and asphalt millings that may limit you in your capability. It’s always a good idea to check at your local municipality or council or inquire at the Homeowner Association to find out what you are allowed to do.
Before you start working on your project, it is important that you know exactly what you are permitted to do, and what standards and applicable regulations need to be followed when using asphalt millings. Asphalt millings requirements will be something you’ll need to find out about first.
What are the Advantages of Asphalt Millings?
As compared to conventional gravel products and traditional paving products, milled asphalt offers an alternative that is more resistant to extreme weather elements and is a more cost effective solution for many projects.
The many benefits of asphalt millings also include cost effectiveness and increased durability and less need for asphalt repair or patching.
So long as the initial installation has been done accordingly, and proper hardening has been done, and it has been properly compacted under normal traffic and damage conditions, the lifespan of asphalt driveways and roads will be a solid 15 years or more with very little maintenance.
Recycling asphalt millings gives us environmentally friendly asphalt paving material, eliminating the need for old pavement installations that have been demolished to go to the landfill.
These are just some of the multitude of advantages of asphalt millings and their use in opposition to traditional gravel and other types of stone gravel and paving material that property owners should take advantage of.
References:
https://ucanr.edu/sites/forestry/files/168246.pdf
https://www.fhwa.dot.gov/publications/research/infrastructure/structures/97148/rap134.cfm