Better Roads Staff
“This is the Cadillac fix in the prevention tool box,” says Galehouse. “You mill off a thickness of deteriorated pavement and overlay with new asphalt to restore the ride quality. It’s a lot cheaper than waiting until you have to do a total structural rehabilitation, but for stretching budget dollars, you want to work as far up the deterioration curve as possible.”
In-place recycling technologies can also be very effective in treating aging pavements, says Galehouse. “It’s important to make sure the project you have in mind is a good fit for the technology, whether it’s hot-in-place or cold-in-place,” says Galehouse. “The best procedure is to get a good, reputable contractor to evaluate the project in terms of its appropriateness for (either).”
When in-place recycling technologies are viable, they bring a cost advantage to the project as well as environmental advantages, such as less energy consumption, lower CO2 emissions, and a 100-percent recycling of the existing resource.
Concrete Pavement Interventions
Contractors and pavement managers have developed an elaborate toolbox for concrete pavement prevention, notes Galehouse.
Joint resealing lies at the low end of the cost spectrum, followed by diamond grinding and partial and full-depth repairs.
“Cost analysis is key, especially with the more-expensive interventions” says Galehouse. “You have to weigh the cost of repair against the cost of replacement. So, for example, if you had to replace every other panel on a stretch of road, it would probably make much more sense to just replace that stretch of road.”
In many cases, says Galehouse, concrete pavements just need diamond grinding to remove surface imperfections and improve smoothness. Over a period of time, concrete slabs can settle due to movement of the road’s subbase. Most of the imperfections occur where the panels abut.
“If you have vertical displacement – called faulting – of the slabs, you might consider retrofitting dowel bars to stabilize the joint and improve the transfer of loading between slabs,” says Galehouse. “If they are tied together, just diamond grind it and seal the joint.”
While some pavement managers aren’t convinced that joint sealing improves concrete pavement performance, Galehouse does advocate the practice.
“The important thing is to keep the incompressibles out of the joint,” he says. Incompressibles include foreign objects that can clog joints and prevent the slabs from flexing as temperatures change and cause the panels to expand and contract. “By keeping joints sealed, you keep out the material that can cause blow-ups,” says Galehouse. “Seals also help protect the pavement from water seeping into the base and creating a ‘pumping’ action that forms voids in the subbase and cause cracks and even breaks in the panel.”
Joint seals typically last 10 to 12 years before leaks appear, says Galehouse.
Does prevention pay off with concrete roads? “If we take good care of our concrete roads with the tools we have today,” says Galehouse, “they will last far beyond what we have come to expect — over 50 years for good concrete.”
Coping with Our Times
There are still pavement managers in America who give their worst pavements first priority in budgeting, Galehouse notes, and their systems are suffering the most from the diminished budgets of the Great Recession.
“In good times or bad, the strategy that makes the most sense is to first keep your good pavements good — your dollars go further and your system stays stronger,” says Galehouse. “Then you keep your marginal pavements from deteriorating any further — to minimize safety concerns and the cost of the ultimate repair. And then you rehabilitate bad pavements as dollars allow, starting with safety concerns.”
Galehouse concedes that today’s tight budgets constrict everyone, but those pursuing sound management strategies that stress prevention will outperform the others, he says.
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