Benefits of in-place recycling.

In-place recycling can reuse all the old pavement back into the highway. The hot-mix asphalt (HMA) plant recycling process can reuse 25 to 35 percent of the old, reclaimed asphalt pavement effectively, by blending it back in with new HMA for a highway project. Overall, about 80 percent of all asphalt materials removed are reused in some type of highway application.

In addition to preserving aggregate resources, other benefits of in-place recycling are the lower cost of construction, reduced fuel use, and lower greenhouse gas emissions. Further, Harrington says, reports from States are showing lower costs for long-term maintenance and improved ride quality over the lifetime of the pavement compared with the conventional mill-and-fill process.

"With the rising costs of asphalt and fuel, the dollar savings for in-place recycling, when compared with the cost for various other rehabilitation options, will really surprise a program manager working with a tight budget," Harrington says. In fact, the cost for in-place recycling can be about 30 percent less then milling and hauling off 5 to 10 centimeters (2 to 4 inches) of pavement and then bringing new HMA pavement (containing at least 20 percent reclaimed asphalt pavement) back onsite. The cost of hauling materials to and from the jobsite greatly increases the overall cost.

In-place recycling also can slow roadway deterioration, facilitate preserving and upgrading a higher proportion of pavements, and avoid costly reconstruction. By reusing existing materials, this cost-effective strategy enables public works officials to spread available funds over a much greater area.

Stacy Stottmeister is a contractor for NHI.