The South Carolina Department of Transportation (SCDOT) has won a 2005 Perpetual Pavement Award for a section of I-20 in Aiken County.
The award will be presented at a ceremony during the International Conference on Perpetual Pavement in Columbus, OH, Sept. 14. SCDOT will receive an engraved crystal obelisk and a plaque and will have its name and project added to a permanent plaque which is kept at the National Center for Asphalt Technology (NCAT) in Auburn, AL.
To qualify for this prestigious award, a pavement must meet strict criteria and demonstrate hot-mix asphalt’s (HMA’s) long-life characteristics, excellence in design, quality in construction, and value to the traveling public. It also must have been constructed at least 35 years ago. Engineers at NCAT evaluated the nominations and a panel of industry experts validated the winners.
South Carolina’s award-winning pavement is a 10.4-mi. stretch of I-20 from the Lexington City Line to U.S. Route 1. Paving on the highway started in November 1969, and it was opened in December 1970. Its structure included 10 in. of a subbase course, 7 in. of asphalt stabilized base, 2.4 in. of a hot-mix asphalt intermediate course and 1.4 in. of an HMA surface course.
Since its opening, the road has been resurfaced only once, from 1983-1985, with two, 1-in. layers of HMA. In all that time, it has carried more than 13 million ESALS (equivalent single axle loads). That is almost 15 times more than the number of ESALS it was originally designed to carry before failure. Even though today’s truck traffic is nine times higher than when it opened, SCDOT remains confident about the pavement’s future performance.
Andrew Johnson, SCDOT pavement design engineer, said that the road’s thick, asphalt stabilized base has been an important factor in its longevity.
“SCDOT built what would today be called a Perpetual Pavement design,” he explained. “Our DOT was very cost-conscious, and wanted to build something that would last a long time but be economical. You could say that this road was unintentionally built to a higher strength than what it was designed for and as a result we ended up with quite a bit of capacity. It’s been a good investment for the people in South Carolina .”