These days, asphalt resurfacing is commonly preceded by cold planing (milling).  While the history of asphalt and concrete pavements goes back to antiquity, the milling machine only came on the scene in the 1970s.  As such, pavement milling is a dynamic part of the field and we owe it to ourselves to keep up with evolutions in milling machines, related technologies, and best practices.

We recently filmed a milling project with the goal of de-mystifying the operation for the un-initiated.  On one level, milling is fairly straightforward, but because most people don’t get the opportunity to see it up close (it’s loud and occasionally throws something at you, so keep your distance), it takes on that “black box” quality.  Our brief video was intended to present the basics, so you have a better understanding of what is going on.  The Pavement Preservation & Recycling Alliance (PPRA) provides an excellent overview of cold planing, breaking down equipment, calibration, quality assurance, and other aspects.

On the other hand, cold planers (milling machines) are highly complex equipment, enabling a remarkable amount of control of grade, profile, and smoothness.  Like other aspects of our field, you can stumble across some informative milling nerds, and they will have you quickly convinced there is a lot more than meets the eye, particularly as we get into things like micro milling.  One such group of milling aficionados are the Asphalt Recycling & Reclaiming Association (ARRA), who teamed up with the Federal Highway Administration (FHWA) for a webinar on Milling Best Practices, which provides a deeper dive into what is exactly going on around that cutting drum and the kind of quality control considerations that can make a real difference as you prepare the road for resurfacing.

Pavement milling deserves a closer attention than some of us give it, because the advancements in what an experienced contractor with a well-maintained machine can produce for us can make a real difference in the ultimate quality of the resurfacing project.  In addition, the advancements are likely to continue, since milling machines are the adolescents among much more mature aspects of the roadway maintenance field.

The Delaware T2/LTAP Center’s Municipal Engineering Circuit Rider is intended to provide technical assistance and training to local agencies, so if you have pavement management questions or other transportation issues, contact Matt Carter at matheu@udel.edu or (302) 831-7236.

Link to Pdf