Engineers at the National Center for Asphalt Technology (NCAT) located in Auburn, AL, evaluated nominations from across the county and validated the results for the Perpetual Pavement Award winners and selected 9.27 miles of roadway in Gainesville, FL to receive the award.
To qualify for this prestigious award, a pavement must be at least 35 years old and never had a structural failure. The average interval between resurfacing of each winning pavement must be no less than 13 years. The pavement must demonstrate the characteristics expected from a long-life perpetual pavement design: excellence in design, quality in construction and value to taxpayers.
The award-winning section of I-75 is a six-lane, divided interstate near Gainesville, running from milepost 0.0 to 9.270. The Florida DOT (FDOT) built the road in 1962 using 12 inches of stabilized subgrade, a 10.5-inch limerock base, a 2.5-inch binder course and 1.5 inches of asphalt as a surface course. FDOT resurfaced the road in 1969 with 1 inch of leveling course and 2 inches of surface course.
In 1981, FDOT again resurfaced the road with 5 inches of asphalt and a .625-inch open graded friction course. From 1992 through 1995 FDOT widened the road to meet the need for additional capacity; at that time it resurfaced the road. Work included milling 3.5 inches from the pavement, adding a .5-inch crack relief layer, adding 3 inches of structural course and .625 inches of open grade friction course. In 2002 FDOT milled .625 inches from the road and replaced it with another surface course.
Despite the continuing increase in truck traffic, the road has not required any additional major maintenance. It carries approximately 60,000 vehicles per day with about 16 percent truck traffic.
Atypical from other Perpetual Pavement Award Winners, this section of I-75 added 7 inches of structural mix during its first 19 years of use; however, it is evident that this was due to the original road being underdesigned for its traffic loading. Since then, it has gone for longer than 13 years, on average, between resurfacing despite carrying 103 million equivalent single axle loads (ESALs) since its initial construction.
Since the last significant structural layers were added in 1981 only the road’s open graded friction course layer has been removed and replaced; FDOT has added only .1 inch of actual structure in the last 34 years. Considering the extremely heavy traffic and the hot, humid Florida environment, the pavement performance has been exemplary.
“The department is honored to receive the Perpetual Pavement Award for the sixth time,” says Brian Blanchard, FDOT’s assistant secretary for engineering and operations. “State Road 93 (I-75) near Gainesville is a 9.27 mile, six-lane section of divided highway originally constructed in 1962. Its last major maintenance occurred in 1995. Since then, with a current annual average daily traffic count of 60,000 vehicles, this pavement has provided excellent service even after facing three hurricanes, 47 inches of annual rainfall and a copious amount of Florida sunshine.”
As a winner of a 2015 Perpetual Award, FDOT will receive an engraved crystal obelisk, and its name and project will be added to a plaque on permanent display at the NCAT Research Center at Auburn University.
Since 2001, the Asphalt Pavement Alliance's (APA) Perpetual Pavement Award program has recognized 100 long-life pavements in 30 U.S. states and one Canadian province. These roads were all at least 35 years old when honored, and had never experienced a structural failure. To qualify, a road could not have had more than 4 inches of new material added over the previous 35 years, and it could not have been resurfaced more frequently than once every 13 years. The winning pavements range in age from 35 years to 75 years, and the average age was 44 years at the time the award was won.
