Preheating of existing pavement

[mitchelon]

Is it common to preheat the existing asphalt before an overlaying job? I’m not a paving expert, but I have been involved in a lot a paving jobs before. It made sense when I saw this the other day for the first time – preheat the existing to create a better bond with the new asphalt – it’s only that I have never seen it before. Any comments?

 

[Ron]

Rarely done, except perhaps in colder climates. Don't let the contractor substitute preheat for proper tack coat.

 

[ACtrafficengr]

Sometimes thay will preheat the asphalt to make it easier to scarify or mill off the top inch or so. Top course asphalt is more susceptable to rutting than binder or base, especially if you have several layers of it.

Heating the asphalt oxidizes the pavement, which makes it more brittle. If you aren't scarifying or hot-in-place recycling, you are better off with a properly applied tack coat, as Ron said.

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