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Repairing rather than replacing a stretch
of Gratiot Avenue saves dollars
By Dave Morningstar
The Capital Preventive Maintenance (CPM) program
is a deceptively simple idea with potentially enormous
benefits for both the motoring public and cash-strapped
state highway authorities. Where conventional maintenance
is purely reactive — such as fixing a pothole after it appears
— preventive maintenance is designed to keep a section of
roadway that is already usable in that condition.
A good example is the recently completed CPM project on 6 miles
of Gratiot Avenue in Michigan’s Macomb County from 8-Mile
Road to 14-Mile Road. The existing roadway consists of a 4.5-inch asphalt overlay on 10 inches of original concrete pavement.
The Repair Plan
The asphalt was moderately rutted, but overall, the road was
in acceptable condition and would probably remain so for
another few years. But after milling off the existing 1.5-inch
wearing course, repairing the base where necessary, and
installing a new 5E30 high-stress Superpave wearing course,
the roadway was returned to top condition at a fraction of the
cost of replacing it.
“The road was in reasonably good shape,” explains Bob Farina,
Estimating Manager at Ajax Paving Industries, Inc. “But it
was showing some signs of wear. The preventive maintenance
work will extend the road’s life by 10 years or more and save
the state the cost of a total rebuild during that time.”
According to Ajax Project Manager Tim Hay, the 5E30 Superpave
wearing course that was installed is a high-performance
material. “It should be essentially rut-free for the whole life of
the upgrade,” he says. “Nobody knows for sure just how long
this new pavement will last, but it will postpone the need for
reconstruction for a number of years and free up the money
for more critical projects.”
For Each, As Needed
For most of the project, Ajax cold milled the existing wearing
course and replaced it with the high-performance Superpave
material directly over the remaining asphalt surface. In areas
with significant damage, the leveling course was also removed
so the underlying concrete could be patched or, in the worst
cases, replaced.
“We’re just filling small cracks with asphalt,” Hay explains.
“For bigger cracks and bad joints, we’re using a minimill to
get down to the concrete and then removing any rotten concrete
with a backhoe. After vacuuming out the debris, we fill
it with hot-mix asphalt and move on. Only the extremely bad
areas get a complete concrete replacement.”
Once that part of the job was complete, Ajax placed the 1.5-inch Superpave wearing course. “It’s a bit more complicated
than an ordinary paving job because you have to carefully
control both the mix and the compaction,” says Farina.
“Fortunately, Ajax has a lot of experience with Superpave
materials, and we have the high-frequency vibratory rollers we
need to place this kind of material effectively.”
All the way through, the job itself went smoothly. The only
unusual challenge Ajax faced was the need to complete the
first phase of the project in time for the annual Cruisin’
Gratiot car event in the city of East Pointe.
“There was some concern about that,” Hay says. “But we finished
that phase of the project with two days to spare. Some
folks thought that was cutting it a bit close, but we weren’t
worried about it; and the cruisers got to ride on some very
smooth pavement.”
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