Cycling in Waterloo Region

[Bytor]

The depth of the freezing is clearly different but we do get frost on the ground some days.

But I’d never heard that it is about frost heaving in winter. Like, that’s usually something that affects subsurface structures mostly. The leaving of asphalt I’ve always been told was about letting the first layer settle and compress under loads before doing the final lift.

Frost on the pavement is not a problem.

Frozen ground absolutely can cause unevenness in the pavement. Not terrible in SW Ontario, but still there, depending on the winter and the location. Not paving the final coat until the following summer is a very logical thing to reduce the risk of frost damage to new pavement.

To elaborate, if you put the second layer of asphalt on too soon before enough settling has occurred, not only can you get the uneven pavement I was talking about, but the layers of asphalt can also potentially decouple, or the bottom layer can decouple from the stones and sand below.

It's not very much, millimetres, but that is now a gap that water can get into. As we all know, water expands when it freezes. That freezing causes the asphalt to buckle and crack, letting in more water.Also, if the water can drain fast enough from the gap it will carry some of the sand and smaller stones with it, leaving a bigger gap for more ice to freeze inside and cause a great amount of frost heave. Multiple cycles of that is what causes potholes.

It's going to happen eventually, but putting on the top coat too soon can make it happen in only a few years rather than 20 years.