Is milling prior to bituminous overlay required?

[mweng]

Is it absolutely necessary to mill prior to a bituminous surface course overlay? Are there other reliable methods to ensure long-term viability of the overlay aside from milling?

 

[bigmaxic]

Oh sure, milling is mostly done for reclamation or when you have too thick of a pavement. Often (depending on a condition of existing pavement) you can clean it up, put a layer of tack coat (asphalt emulsion), and pave right then.

 

[mweng]

I thought milling was performed to also provide better binding between existing and new bituminous courses. Do you see any of these overlays peeling up (that is when you don't mill)?

 

[bigmaxic]

As I said before, milling is done for two main reasons: you need to reclaim a very bad surface (patched, crack sealed, change of grade etc), or reduce thickness of existing pavement.

For example, you have an old road which was paved over several times without change of curb. The curb became from 12 in tall to 2 in tall. Another paving will make curb invisible, so you mill to allow more top to be put down.

Milling, specifically, for a better binding action is a waste of money (unless you really wanna do it), most of the time it is not done. Besides, you will still need to put tack coat on a milled surface before top course.

I mean, a price of milling is about $2/SY these days. Do you want to charge/pay $12000 for 0.5 mile stretch of 2-lane road if it's not worth it?!

No peeling, unless it is poorly paved (tack coat)