What happened to I-440? It simply wore out, despite the grooves cut into the roadway to extend its life.

“The existing concrete has really lived its service life for us,” says Clayton Markham, TDOT operations district manager and I-440 project manager.

“It wasn’t designed for the traffic that it has on it now, and with the potholes and everything, it’s lived it’s service life. It’s done well for us but it’s time to replace it.”

The existing concrete that makes up 440 is being reduced to rubble, a process that involves digging it up, breaking it up and recycling it into a base for the asphalt that will replace it. It’s a process that saves time and money and reduces the amount of time the project will be under construction.

“The department’s chosen to go with asphalt paving for several different reasons,” Markham says. “One of them being maintenance. A lot of times maintenance on asphalt pavement is a little bit quicker than it would be on concrete pavement. You can get in, you can do work in an isolated area and get it done pretty quickly, whereas concrete takes a little bit of time for the concrete to set up.”

Will Reid, assistant chief engineer at TDOT, says that when it came to deciding exactly how to go about redoing 440, the agency had to take into consideration how to keep cars moving while still doing repairs in a reasonable amount of time.

“The way that you build it is important as far as the impacts to the public. Asphalt gave us a little bit more flexibility with the pacing of building it,” Reid explains. “With concrete, there is not the ability to come in there and resurface as easily as with an asphalt pavement.

“Now concrete can last 30 years. In the past, the concrete that was used at the time 440 was built, the technology was such that concrete was a better product when it came to track traffic. But the technology in asphalt pavements has evolved to the point where they are very close in performance.”

Still, today’s asphalt is not forever.

“We design our projects to be perpetual pavements, meaning that we will build a base structure within pavements that we intend to stay for 30, 40 years and then we resurface on a cycle, depending on the nature of the facility,” Reid says.

For instance, interstate highways are resurfaced on an eight-year cycle. On major state routes, the resurfacing happens on a 12-year cycle.