New asphalt needs time to cool before you allow traffic on it, which is known as “asphalt curing time.” Unlike concrete which “cures” in the first few days of installation, new asphalt can be driven on as soon as it’s rolled and cool.
Too many variables exist to give an exact amount of time your parking lot or road will be closed. Some of the variables that impact asphalt curing time are:
- the type of asphalt repair
- the ground temperature
- the air temperature
- the size of the rollers used
However, if there is any practical way to keep your new asphalt from being driven on the day it’s laid, it’s best to wait until the next morning.
What Happens During Asphalt Curing?
The curing involves the asphalt oil. When asphalt is first placed, it is black in color. As the new asphalt ages, it slowly turns from a black color to more of a gray color. This is because your new asphalt is slowly losing its oils due to the sun, a process called “oxidation.” This oxidation is actually a good thing as new asphalt has too much oil in it when first placed.
Due to this excess of oil in the asphalt, a vehicle that stops cold on new asphalt and then turns their power steering from a dead stop can make what is known as a “power steering tear,” actually scraping up portions of your new asphalt surface. This is especially true on residential driveways as cars maneuver to go into garages.
Allowing Asphalt Curing Before Sealing
After laying asphalt, it’s recommended to wait 30 days before sealing a commercial parking lot and 90 days before sealing a residential driveway. You don’t want to seal your new asphalt until the asphalt is hard enough to withstand power steering.
Sealing new asphalt will stop the oxidation process and, if done too early, cause a pavement to retain too much of its asphalt oils. However, once new pavement has oxidized enough to lose the asphalt oils necessary to withstand power steering, it’s time to seal your new asphalt.
If the new asphalt is never sealed the oxidation process never stops, causing the pavement to lose too much oil. Since the asphalt oil in your pavement is the glue holding the asphalt material together, losing too much of your pavement’s oil will cause the rock and sand material from your pavement to unravel.
As you can see, ensuring proper asphalt curing time is a pretty important step in the paving process. If you have any questions about asphalt curing time given your particular situation, let us know.
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