Milling and resurfacing are often spoken about as competing options. On many jobs, they are two parts of the same plan.
Milling removes existing asphalt to a controlled depth. Resurfacing places a new asphalt layer. The question is not always which one to choose. It is how much needs to come out before new pavement goes down.
What milling accomplishes
A milling machine removes the upper portion of asphalt and loads the reclaimed material for transport. Depending on the scope, milling can:
- remove distressed surface material;
- correct bumps, shallow ruts, or an uneven profile;
- create room for a new layer without raising the final elevation too much;
- preserve curb, drain, threshold, and bridge clearances; and
- provide a textured surface for the next course.
FHWA describes cold milling as controlled removal to a desired depth and restoration of the surface to a specified grade and slope. That precision is the point.
What resurfacing accomplishes
Resurfacing installs a new wearing course over prepared pavement. It can restore ride quality, surface texture, and appearance when the pavement below remains capable of supporting traffic.
It does not automatically fix failed base, active movement, drainage problems, or deep structural distress. Those areas may need full-depth repair before the overlay.
Why elevation matters
Adding asphalt without removing any can create trouble at curbs, gutters, doors, drains, utility covers, accessible routes, and adjacent concrete. Milling can preserve those relationships.
Ask the contractor for the planned milling depth and the compacted thickness of the new asphalt. Those are different measurements and should both appear in the proposal.
Look below the surface
Before choosing a scope, map the failures. Isolated soft spots may need undercutting or full-depth patching. Widespread alligator cracking or movement can indicate a broader support problem. Water entering through cracks or collecting at low spots needs its own plan.
A core sample or other investigation may be reasonable on a large project. The goal is to avoid placing a new surface over a failure that will quickly reflect through.
Questions for the quote
- Which areas will be milled, and to what depth?
- Which areas need full-depth repair?
- How will transitions and utility structures be handled?
- What is the compacted thickness and mix for the new course?
- How will the milled surface be cleaned and bonded?
- How will drainage and final elevations be verified?
- Where will the reclaimed material go?
Milling is removal. Resurfacing is replacement of the wearing surface. A good paving plan connects them to the actual condition underneath.