One question we often hear at Calvac Paving is about asphalt cure times. This is a great question because understanding how the asphalt curing process works helps you understand when you can safely stripe, park, walk, and drive on the new asphalt parking lot and what sort of performance you can expect from your asphalt long-term. Let’s take a closer look at how the asphalt installation process works and how this affects the asphalt curing process!
Asphalt Surface Installation
Most asphalt paving companies prefer not to place a fresh asphalt surface if the ambient temperature is outside the range of 50°F-90°F. If it’s too hot, asphalt will not cure quickly enough. Paving when it’s too cold can cause the asphalt crack as it rapidly cools. Weather conditions can make a difference as well. If you watch carefully, you’ll notice paving companies rarely place asphalt in heavy rain. While it is possible to pave asphalt outside these parameters, it requires special preparation and oversight.
The rules for hot asphalt patch, resurfaced asphalt sealcoating and cold patch asphalt placement are a little different, so for purposes of this discussion, we’re going to focus on a clean installation on grade for commercial or residential paving like parking lots or a driveway.
How Long Does Asphalt Take to Cure?
The curing time for asphalt depends on the asphalt mix design, the oil content, the temperature of the mix, the thickness of the paved asphalt layers after compaction, and the temperature and weather conditions when the mix was placed. Generally, you can open new asphalt to public foot and vehicle traffic 48-72 hours after it is placed because this allows time for the asphalt to harden, but you may need to allow a bit more time during hot weather. Asphalt doesn’t fully cure for 6-12 months, so it’s important to keep a close eye on it during this time because it will be less resistant to damage.
The reason we stress the difference between “curing time” and “asphalt drying time,” even though they’re often used interchangeably is that asphalt is designed to be flexible. For it to remain flexible, it has to retain a certain amount of moisture. Water infiltration in paved asphalt driveways, parking lots, roadways, speed bumps, and other asphalt surfaces is the primary factor leading to a blacktop drying out. The water washes away the oil which keeps the asphalt overlay flexible and resilient. You can tell when asphalt dries because you’ll notice cracking, warping, raveling, and loose aggregate appearing on the surface of the matrix, especially sand and other fine aggregates. Fortunately, it takes months to years of asphalt drying time to start noticing signs other than cracking.
What Can I Do to Not Allow My Asphalt to Dry Out?
Good roadway and parking lot maintenance programs can help prevent a lot of problems. Putting down asphalt seal coating on a regular basis, especially when you freshen up your street or parking lot striping, can help prevent more costly asphalt repairs down the line. This is also a great time to do any basin repairs and crack filling, as catching these problems early, when they’re small, can keep your asphalt fresher and more flexible for a lot longer.
Asphalt sealer drying times vary, but 4-8 hours to dry is usually enough for your sealer to ensure it will keep water out. However, the full drying process for the sealer takes around 24 hours, and it’s important to allow your sealcoating to dry completely before line striping for maximum resiliency and effectiveness. As with any other kind of asphalt sealant, you want to allow crack sealer to cure for at least 24 hours in perfect conditions, and add a day for cool, cloudy, or high-humidity conditions just to be on the safe side.
Final Thoughts About How Long It Takes Asphalt to Dry
Of course, the best mix design in the world won’t do you any good if it’s improperly placed, if your striping doesn’t meet the latest ADA criteria or if you don’t take proper care of it. For the best possible results and the greatest confidence in your paving job from breaking ground to the final walkthrough and for years of use beyond, click here to contact Calvac Paving. We’ve been proudly serving the Bay Area since 1972 on residential, commercial, and government projects of all types. Our track record for consistent quality, service, and excellence in every aspect of our operations speaks for itself. Put our experience to work for your paving refurbishment, repair, or new construction needs and see why Calvac Paving is the contractor you need for paving that works the first time, every time!