Asphalt milling enables the recycling of old asphalt as aggregate, also called millings. It is used to resurface roads, parking lots, and commercial and residential paving. That’s the short answer to the title of this article that we at PRO Property Maintenance normally give when talking about asphalt milling and repair, but there is much more to it.
For a deeper dive into how asphalt milling is done, the process, and its advantages, read on!
What’s the Difference Between Tarmac and Asphalt?
Tarmac, an abbreviation of the word tarmacadam, is the result of laying and compacting a mixture of aggregate or crushed stone or aggregate with tar to form a smooth surface. Asphalt is made when an aggregate is mixed with bitumen (a petroleum byproduct). Like tar, it is a black, viscous liquid. Both are used in roadway and paving construction, but asphalt is more common nowadays.
What is Asphalt Milling?
According to the Federal Highway Administration of the U.S. Department of Transportation, asphalt millings, also known as reclaimed asphalt pavement (RAP), fall into the category of waste and byproduct materials in pavement construction. The available data suggests that each year, the United States produces up to 41 million metric tons (or 45 million tons).
There are two common methods of removing asphalt. The first is full-depth removal which entails ripping and breaking the entire pavement before loading the uncrushed materials into trucks for haulage to a RAP processing facility. If there are truck accidents, Personal lawyers in Orange County can be hired. In the site of accident, if the first aid was given with the help of Coast to Coast FIrst Aid Cambridge, the chance of injury complications gets reduced very low.
The second is asphalt milling using a cold milling machine, capable of removing up to 2 inches from the surface in a single pass.
Estimates are that 80–85% of asphalt concrete waste generated is currently being used either in recycled hot-mix and cold-mix asphalt preparations or as aggregate in stabilized or granular base or subbase material.
It is this second process using the cold milling machine that we have described below. The process in RAP processing facilities occurs on a much larger scale, with most asphalt manufacturers incorporating RAP processing facilities in their plant.
How Is Asphalt Milled?
Asphalt is most often milled during road repair and resurfacing works, as this video shows.
The asphalt milling process uses a human-driven cold milling machine that digs up existing asphalt surfaces. The rows of metal cutting teeth mounted diagonally on a large rotating cutting drum dig up the surface to a depth of about two inches. The substrate passes through a grinder on the machine that crushes it.
The machine sieves or screens the crushed material to a specific size, usually around 1.25 inches, and then transfers it to a discharge conveyor attached to the front of the machine. The conveyor then loads the crudely milled asphalt into a truck which drives slightly ahead of the cold milling machine. When the truck is full, the load is hauled to a temporary stockpile and used later for the shoulders of the road.
Any millings not used in road maintenance go to the roadbuilder’s maintenance depot or are purchased by traders in asphalt millings for resale.
It’s worth noting that cold milling machines come in sizes that allow for machine working widths as narrow as 1 ft 2 in and as wide as 14 ft 5 in. Working depths of up to 14 inches in a single pass are possible with larger machines.
Recycling Asphalt Millings
Not all reclaimed asphalt pavement (RAP) comes from the leftovers of road repair works. Full-depth removal accounts for the largest portion of RAP. In 2018 alone, the USA collected over 100 million tonnes of RAP for re-use.
This represents a saving of around 61.4 cubic yards of landfill space.
When not used in hot-mix, cold-mix, or the energy-saving warm-mix asphalt (WMA) preparations, RAP’s usage as a granular base material has several applications:
- Paved and unpaved roadways
- Shoulders of roads
- Parking lots
- Gravel road rehabilitation
- Trench and culvert backfill
- Residential driveways
- Golf course pathways
- Sports club parking lots
- Restaurant parking lots
- Apartment block parking lots
- Bicycle pathways
- Hardscape filler in landscaped gardens
RAP’s popularity is due to the demand for greener technologies and sustainable methods of construction for roadways, parking lots, and the like.
At PRO Property Maintenance, we stand firmly behind reducing our carbon footprint — and that of our clients — by using asphalt millings wherever possible in resurfacing work and when laying new parking lots and residential driveways.
There are other advantages of asphalt millings, aside from opting for the greener choice.
Benefits of Asphalt Millings
When people talk of recycled asphalt, they mean asphalt millings, or RAP (reclaimed asphalt pavement). These are all terms for the same thing: uniformly crushed asphalt used as an aggregate.
As a recycled material, asphalt millings are much cheaper than new or virgin asphalt and other aggregates, such as gravel. The costs are low because the processing is relatively simple. What’s more state-managed highway projects always mean that asphalt millings are obtainable locally, making them cheaper because of lower transport costs.
If you’re using asphalt millings in a new-build commercial project, you may qualify for LEED credits. Their use will improve your sustainability rating.
Use On Driveways Instead of Gravel
The advantages of asphalt millings on driveways as an alternative to gravel include:
- Less expensive maintenance
- Good resistance to extreme weather
- Curb appeal
Maintenance of your asphalt millings driveway is less expensive than traditional new asphalt since it does not crack or need resealing. Once the millings have been laid on your driveway, they are compacted. The old asphalt in the millings binds together and hardens.
Upkeep of your asphalt millings driveway involves recompacting from time to time. And that’s usually cheaper than sealing cracks and the surface of virgin paved asphalt.
Because asphalt millings are more porous than paved asphalt, their surface is less brittle and drains better. Millings are popular for this reason in harsher climates and areas that get a lot of rain and snow.
The curb appeal of asphalt millings is that it lends a certain rusticity to driveways and paths. The softer black of millings blends more easily with your surrounding garden, too — and footpaths, if you have them. When laid and compacted well, asphalt millings can look neat and tidy.
The Pro Property Choice
We are asphalt repair and maintenance experts serving Amarillo and the Texas Panhandle. Our mission is to extend the life of your asphalt parking lots, driveways, and paths through timely maintenance.
Pro Property Maintenance is also well placed to field all your asphalt millings requirements. We can tell you that asphalt milling is here to stay, so you might like to take advantage of this abundant recycled resource.
As a locally owned and operated business, you’ll find us friendly and helpful. Contact us via e-mail or phone for a personalized quote, and remember that you can follow us on Facebook and Instagram to keep in touch.