If you’re using recycled asphalt millings to repave your driveway (or to complete another construction project), you’ll most likely need to compact and melt them with a steamroller for them to harden completely and properly. Once the asphalt has cured, you’ll need to apply an asphalt sealant to help protect the new surface. Find more details on how to harden asphalt millings below.
How to Make Recycled Asphalt Hard
Recycled asphalt paving, also known as RAP, can be a cost-effective and eco-friendly way to repave a driveway. RAP can also stand up to harsh weather conditions like excessive rain, ice, and snow, which can be especially beneficial if you live in an area with harsh winters.
However, the specific steps for how to lay asphalt millings — including the proper way to harden the recycled asphalt — vary depending on what type of mix you get. According to the Federal Highway Administration (FHWA), there are two main categories: “hot mix” and “cold mix” asphalt.
Hot mix asphalt is, as the name suggests, hot, and must be placed with an asphalt spreader. After laying hot mix asphalt, it takes about 30 days to cure. After curing, it should be sealed with an asphalt sealer.
DIYers are much more likely to use cold mix asphalt — a mixture of asphalt millings placed, spread, and compacted at “ambient air temperature,” as the FHWA puts it. In other words, cold mix asphalt is laid and cured without first being heated. This type of asphalt may harden by itself over time, according to several DIY sources and forums. However, expert asphalt layers like Dykes Paving and Asphalt Recyclers Australia advise that the correct way to finish it is to compact it with a steamroller. After steamrolling, the asphalt must be allowed to cure for at least 24 hours and then finished with an asphalt sealer.
It is possible to rent a ride-on steamroller to compact cold mix asphalt. Rates vary depending on your location, the type of roller, and the size of the roller. Typically, rental prices range from about $100 to $350 per day from national equipment rental companies like Sunbelt Rentals and BigRentz Equipment Rentals but may be higher. It’s also possible to complete most of the project yourself and hire a construction professional to finish your driveway.
The exact procedure for how to make recycled asphalt hard depends on the type of asphalt you use for your project. If using cold mix asphalt for a DIY driveway repair or similar projects, a steamroller is the best way to harden your new recycled asphalt surface, although it may also harden by itself over time.
Wondering how much this project is going to cost you? Check out our article on the prices of asphalt millings and crushed concrete for a pricing guide, as well as some tips, tricks, and specific contacts to help you get started.