Over the years, our city streets deteriorate, and they often are plagued with potholes and uneven surfaces. When slated for resurfacing, the process typically involves bringing in new material and hauling the old asphalt to the landfill.
However, a new method termed "cold in-place recycling" is available. It removes and reuses the existing asphalt surface at the same site. Thus, the materials are mixed in place without the application of heat.
Cold in-place recycling involves grinding off the top 2 to 5 inches of asphalt surface and mixing the crushed asphalt with an asphalt-recycling agent.
The resulting material is applied back to the original road with a paver.
The cold in-place process often is performed using a "train" of equipment, which includes an emulsion tanker, a milling machine, an asphalt paver and a combination of pneumatic and vibratory rollers.
Some of the advantages of using cold in-place recycling are a higher production rate, reduced cost, minimum traffic disruption, reduced use of petroleum resources and little if any material sent to the landfill.
Hilliard estimates that roughly 210 tons of asphaltic material will not be sent to the landfill for disposal.
Disadvantages include an increased curing time needed to attain the needed strength and restrictions on applying during low temperatures and rainfall.
The cold in-place recycling paving process soon will be employed by Hilliard's service department when a section of Scioto Darby Road between Heywood and Reed Point drives is resurfaced as part of the city's annual street-maintenance and rehabilitation program. This year, approximately $1.4 million will be spent on road repairs.
The Scioto Darby project will be the first time the cold-in-place process has been used in the city, so we will be watching it very carefully and evaluating the viability of the process for future projects.
The resurfacing will take several weeks to complete and will cost approximately 15% to 20% less than using the older conventional method of bringing in new material and sending the old asphalt to the landfill. This process also should add a few inches to the shoulder of the road so that it is safer and more comfortable to drive.
This project is another way the city of Hilliard is working hard to become a model community for sustainable practices.
Greg Smith is a member of the Hilliard Environmental Sustainability Commission.