Raleigh, N.C. — Inspectors testing an 18-mile stretch of Interstate 795 from Wilson to Goldsboro followed all state standards and policies but the standards themselves were inadequate in making sure the roadway would be able to handle traffic.

That's according to final findings released Thursday from the North Carolina Department of Transportation that a combination of "extremely dry" pavement mix and "marginal asphalt pavement thickness" caused premature cracking on a 2.5-mile stretch of the highway's pavement.

The $120 million I-795 opened in December 2005, but within the first 16 months of being opened to the public, the pavement began failing, leaving large cracks and numerous potholes on part of the interstate.

The DOT said that marginal thickness of the pavement made it more susceptible to the damaging effects of traffic along the route and that the low amount of binding cement material may have contributed to the poor performance of the pavement.

Even without any issues with the mixture, testing would have predicted a shorter pavement life than the DOT wanted.

"The fact that this pavement began to exhibit signs of distress soon after the project was completed has been a matter of great concern," the DOT's chief operating officer, Jim Trogdon, said. "Since this problem was first discovered, we have been working to determine its underlying cause, correct the issue and prevent it from happening again."

As a result of its findings, the DOT has changed its standards and is reviewing its process and criteria for certain mixtures.

"The goal is to keep this from happening again in North Carolina," Trogdon said.

In January, the Federal Highway Administration recommended removing existing surface layers of the pavement and repaving the entire 18-mile stretch with 3 inches of surface.

The DOT said Thursday that it will repave by the end of the winter, the entire 18-mile stretch with 3 inches of surface at a cost of an estimated $13 million.

Because the DOT discovered the issue four months after its 12-month warranty on the highway had expired – an administrator said an extended warranty was purchased because of the cost increase – it will have to pay for the project.

Officials are still determining how, Trogdon said. The cost comes at a time when the department has limited funds and one of the worst budget crises in state history.

"We're still working on, not only on when to schedule repairs but the funding source," he said. "Utimately, the DOT will pay. Ultimately, the taxpayer."

The problem has already cost the state $1.8 million to repair some of the larger cracks and potholes. Those repairs were complete last fall.

This is not the first time the DOT has had problems with crumbling pavement along a major roadway.

In 2007, it spent about $22 million to repave a 10.6-mile stretch of Interstate 40 in Durham after finding that expansion joints were improperly constructed when new concrete was laid on top of the old during a widening project.