For commercial parking lots, streets, or industrial roadways in the Twin Cities, an asphalt mill and overlay is the most cost-effective asphalt repair and rehab method. At Bituminous Roadways, we have spent more than 80 years paving and protecting the Twin Cities' infrastructure. To help you maximize your pavement management budget, our engineering experts have answered the five most common questions you have about the mill and overlay process. 

Quick Summary: Asphalt Mill & Overlay

  • The Process: A specialized milling machine grinds off the damaged top layer of asphalt, which is replaced with a brand-new, smooth layer of hot-mix asphalt. 

  • The Cost Benefit: It restores the structure integrity and appearance of your surface for a fraction of the cost of a full-depth replacement. 

  • The Lifespan: A professionally installed overlay typically adds 10 to 15+ years of service life to an existing pavement structure. 

  • The Eco Factor: Removed asphalt is completely recycled and repurposed into new mixes at local asphalt production plants. 

1. What is a Mill and Overlay? How Do Mill and Overlays Work?

A mill and overlay is a two-part pavement rehab process designed to correct surface defects in asphalt without disturbing the underlying aggregate base. 

  • Step 1: Mechanical milling removes the top 1.5 to 2.5 inches of damaged asphalt. 

  • Step 2: Prepping the surface involves sweeping away debris and applying a bonding tack coat. 

  • Step 3: New asphalt is overlaid to create a fresh, smooth, and compact surface layer. 

2. How to Tell if My Twin Cities Surface Needs a Mill and Overlay vs. Total Reconstruction?

The determining factor of whether you can schedule a mill and overlay or if you need a total reconstruction comes down to the health of your subgrade base. 

  • When to Mill and Overlay: If your asphalt exhibits widespread surface cracking, minor potholes, or a structurally raveled, textured surface, but the underlying stone foundation is firm and structurally sound, a mill and overlay is ideal. 

  • When a Full Reconstruction is Needed: If your pavement has severe structural depressions, deep rutting, or extensive “alligator cracking” accompanied by shifting ground, it indicates subgrade failure. In these instances, capping the failure with a new layer will only cause the old defects to rapidly push to the surface. 

3. Can Milling Fix Standing Water or Drainage Issues?

Yes, to some extent. One of the greatest technical advantages of a mechanical mill and overlay is the ability to adjust the milling depth across different areas of the pavement. By altering the slope profile during the grinding phase, a skilled operator can smooth out the contours of your lot or surface. This allows the technician to re-establish proper grading, eliminate low spots where rainwater pools, and successfully direct storm runoff toward your catch basins and drainage systems. 

4. What Happens to Old Asphalt?

A mill and overlay is a sustainable option for repairing the surface of your parking lot or road. When Bituminous Roadways mills a road or parking lot, 100% of the scraped material–known as asphalt millings–is collected and hauled directly to one of our three strategically located Twin Cities asphalt plants. 

At our facilities, these millings are crushed, screened, and recycled back into eco-friendly asphalt mixtures. This value-engineering approach keeps tons of construction waste out of Minnesota landfills and lowers overall material costs for our clients. 

5. How Much Operational Downtime is Expected for a Mill and Overlay?

We understand that closing your commercial parking lot means disrupted business operations. Fortunately, a mill-and-overlay project is significantly faster than a total reconstruction. 

While a full tear-out can take weeks, a mill-and-overlay can often be completed in phases or in a single weekend. Vehicles can often drive on a milled surface temporarily if necessary, and a newly paved asphalt overlay can accept heavy traffic within just a few hours after final compaction. 

Consult Bituminous Roadways for Twin Cities Asphalt Projects

Weathered parking lots and roadway damage can affect your property’s curb appeal or invite liability claims. Instead, invest early in pavement maintenance with a trusted contractor like Bituminous Roadways. Our three local plants and over seven decades of experience make us the best choice for your Twin Cities mill and overlay project. 

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