In March 2002, the Executive Director of the Federal Highway Administration, Frederick Wright, Jr., wrote in a memo:
The same materials used to build the original highway system can be reused to repair, reconstruct, and maintain it. Where appropriate, recycling of aggregates and other highway construction materials makes sound economic, environmental, and engineering sense. The economic benefits from the reuse of nonrenewable highway materials can provide a great boost to the highway industry. Recycling highway construction materials can be a cost-saving measure, freeing funds for additional highway construction, rehabilitation, preservation, or maintenance…
In Part Two of this editorial series, focusing on the financial challenges faced by the Archuleta Board of County Commissioners and their Road & Bridge Department, I mentioned four common factors that can cause asphalt roads to disintegrate.
1. Poor drainage. Water is an enemy of asphalt pavement.
2. Badly installed road-base and sub-base — the thick layers of larger rocks underneath the asphalt layer that support the repeated weight of the vehicles. Many Archuleta County roads were built, back in the 1970s, without optimal road-base or sub-base.
3. Insufficient thickness of the asphalt layer. In the case of some paved County roads, asphalt that is thick enough in some sections, and too thin in other sections.
4. Lack of maintenance. Asphalt pavement needs to be properly maintained to have the best possible lifespan. Historically, Archuleta County has neglected to maintain certain paved roads.
There’s a fifth factor.
5. Traffic. A paved road — well engineered and properly constructed — might last 30 years if adequately maintained. But heavy traffic and heavy vehicles — garbage trucks and dump trucks and construction equipment — can shorten the life of a paved surface.
40 miles of our County roads are paved. About 300 miles are ‘gravel’.
At the April 2 BOCC work session, Public Works Director Mike Torres told the commissioners he planned to have a Kansas-based company called Dustrol recycle the asphalt on about 8 miles of paved County roads. Dustrol’s method is to mill up about 2 inches of the road surface, heat the ground-up asphalt to a proper temperature, and lay it back down on the same roadway.
Mr. Torres noted that this technique has been used by the state of New Mexico to resurface Highway 84 immediately south of the Colorado-New Mexico border. He also suggested that the ‘Hot In-place Recycling’ (HIR) method will provide a new road surface at a much lower cost than full reconstruction. A full reconstruction of 8 miles of failing roadway would cost the County around $8 million; the HIR recycling will cost perhaps $800,000.
A good deal, for the taxpayers?
Milling and replacing 2 inches of a road surface will make everything look and feel new. But, as I understand the process, it does not address certain underlying problems, if they exist: drainage problems, nor badly laid sub-base, nor insufficient or uneven thickness of the asphalt.
One of our Daily Post readers sent me an email yesterday, indicating a concern about asphalt paving, where underlying problems are not addressed. He was writing about a different town, but a similar issue…
The road in front of my house was paved with asphalt when the subdivision was originally platted in the late 1970s. We built our house in 1989, and I don’t know if the road had been repaved in the interim. We had potholes, cracks, and the edges were crumbling.
About 10 years ago the County repaved our road for the first and only time since we’ve lived here. At the time, the neighbor across the street (a civil engineer) was a manager in a company that did major road re-surfacing — the project he was supervising at the time ran the length of the county (72 miles). He knew a thing or two about the subject.
The morning of our re-surfacing, I saw my neighbor talking to a member of the road-surfacing crew preparing the area in front of our homes. (Turned out to be the crew supervisor.) I was on my way to work, so I didn’t hear the conversation, but that evening my neighbor was standing in his yard looking at the completed work.
We spoke. He said the re-paving was complete, but that he’d be surprised if it lasted 5 years. He said he had told the crew supervisor that they were not properly repairing the sub-surface before repaving, and the potholes would return after just a couple of rainy seasons. The supervisor had said they were following the specs the County road department had given them.
My neighbor then pointed out to me, specific places in the road where pot holes would develop — one being at the edge of my driveway.
That neighbor has since moved away, but sure enough, within 5 years, a depression in the road began to appear just where he said it would, near my driveway. Now, 10 years post-resurfacing, that depression is well on its way to being a pot hole.
Of course, this is an anecdotal story — about one particular repaving job in one particular neighborhood, that appears unlikely to last 30 years.
What can we learn about the success and longevity of Hot In-place Recycling projects? Is the Dustrol ‘MARS’ (Mobile Asphalt Recycling System) truly a feasible approach to fixing our paved County roads?
To learn more about Dustrol, I watched a 30-minute video shared by the National Center for Pavement Preservation, established by Michigan State University in 2003 to lead collaborative efforts among government, industry, and academia to improve the art of pavement preservation. You can watch the video here… it’s fairly technical. The fly-over of the process begins at about 12 minutes.
One thing I learned from watching this video. Dustrol can sometimes re-surface two miles of paved road in a single day. At that rate, the 8.2 miles of road specified by County Public Works Director Mike Torres could, theoretically, be completed in a single week… if it were not broken up into various segments in different parts of the county.
Apparently, following the ‘recycling’ process, the road needs to then have a chipseal or asphalt overlay applied. As I recall, Director Torres had mentioned chipsealing as part of the 2024 recycling project.
Finally, I learned that Dustrol’s recycling system is not appropriate for all roads, and thorough inspection and investigation is necessary to determine whether the technique can be beneficial. Past Archuleta County Public Works directors have indicated that some County roads were poorly engineered and poorly constructed back in the 1970s. We’ll see…
The Federal Highway Administration’s ‘FHWA Recycled Materials Policy’ was updated in September 2015. You can read it on their website.
Bill Hudson began sharing his opinions in the Pagosa Daily Post in 2004 and can’t seem to break the habit. He claims that, in Pagosa Springs, opinions are like pickup trucks: everybody has one.