Asphalt Paving Season

Is There a Best Time to Install Driveway Asphalt? Yes.  Read on…

You’ve seen highway road crews laying down asphalt in the worst of conditions. So you might think: how hard can it be to lay down asphalt on my driveway?

Hot-mix asphalt is finicky and its installation depends mainly on the temperature of the air and of the surface. The National Asphalt Pavement Association recommends that contractors stay away from laying down “low lifts” of asphalt in very cold temperatures. A “low lift” is basically the height of the layer of asphalt. A low lift is 1.5 inches; a high lift is 3 inches.

Remember that depth does matter in the case of laying down overlay versus full-depth asphalt paving.

The worst-case scenario would be a low lift of 1.5 inches laid in 40 degrees F. Asphalt workers need time to manipulate the hot-but-cooling-rapidly asphalt mixture. Think of when you spread out hot food on your plate to cool it down. Spreading a thin layer of, say, mashed potatoes hastens the cooling process. But cooling, while good for food, is fatal for hot-mix asphalt.

The same 1.5 inches of hot-mix asphalt is still a dicey proposition up to 60 degrees F. Only above 60 degrees does this 1.5 inch lift become workable.

See our chart showing the “window of opportunity” for laying hot-mix asphalt.

Now let’s double the lift from 1.5 inches to 3 inches. The 3 inch lift is perfectly capable of being worked at 40 degrees F. It’s not the best temperature, but it can be done. The paving crew has a full 46 minutes to work with this higher lift, as opposed to only 16 minutes with the lower lift at the same temperature.

And 16 minutes is such a short time to work the asphalt that most contractors will refuse to take on such a job. If it’s too cold for asphalt and you’re desperate, consider laying a concrete driveway.