Construction crews recently embarked on the total reconstruction of the original Pennsylvania Turnpike — the first-ever, complete restoration of the toll road since it was built nearly 60 years ago.

When it opened for business on Oct. 1, 1940, the Turnpike linked southcentral and southwestern Pennsylvania with 160 miles of roadway running between Carlisle and Irwin. Although numerous improvements have been made to the road since then, never before has such a major upgrade been undertaken.

The roadway improvement initiative will take place in phases. Eventually, the entire 160-miles of original road — recognized as "America’s First Superhighway" — will be entirely renewed.

The first three reconstruction projects are currently under way (see the accompanying chart). An additional four projects are in the "design" phase. Construction is scheduled to begin on these four projects in the next 2-3 years.

"The reconstruction of the Turnpike is one of the Commission’s most important, long-term initiatives," said Executive Director John Durbin. "Over the next decade, we expect to spend more than $1 billion to rebuild the Turnpike at an approximate cost of $5 million per mile. Compare that to the $450,000 per mile to construct the first roadway, and you can see tremendous amount of resources it now takes to operate a highway system like ours."

According to Turnpike officials, the rebuild is much different than the original highway. Road-making technology has made significant advances in the ensuing years, and today, engineers must design the roadway for much heavier gross vehicle weights and a substantially higher traffic volumes than was the case in 1940. In its first full year of operation, 2.4 million vehicles traveled the Turnpike; in 1998, almost 156 million cars and trucks used the road.

The rebuilt section is also structurally and materially improved. Designers have taken several measures to make sure that this road will stand up to the rigors of Pennsylvania’s brutal wintertime weather and the stresses of the millions of vehicles that annually pass over the Turnpike.

"Water is a roadway’s worst enemy," said Gene C. Mattson, the Turnpike’s materials management supervisor. Engineers are especially concerned about the sub-surface water that cracks the roadway when it freezes and expands. This is particularly a problem in Pennsylvania, with its drastic freeze-and-thaw cycles that often take place in the course of 24 hours or less.

"Therefore, we’ve gone to great lengths to protect the rebuilt roadway from water infiltration and resultant surface damage," said Mattson. An asphalt-treated permeable base allows runoff to seep down through the road, and a multifaceted sub-base drainage system carries that water away from the roadway.

Innovation lies not only beneath the roadway’s surface, but on the top as well. Instead of using concrete to build the new road, constructors are using a newly developed process known as Superpave. Superpave — which gives the new roadway a 15 year life span — creates an asphalt surface that is more resilient to weather and that resists rutting caused by today’s hefty trucks that weigh as much as 125,000 pounds. Superpave does this not only with its special formulation of aggregate and asphalt, but how the material is tested, mixed and applied at the work site.

Another innovative aspect of the total reconstruction project is the use of recycled materials. A subcontractor has set up a crushing plant near the reconstruction site. Large slabs of the original highway are excavated and hauled in giant dump trucks to the plant, which crushes the slabs into an aggregate material and removes the steel reinforcing rods. The recycled aggregate — a gray, pebbly material seen in huge heaps near the reconstruction zone — is hauled back onto the roadway to be used as a sub-base.

"Recycling the old concrete roadway minimizes the amount of waste that we have to contend with," said Brad J. Heigel, P.E., project manager for the current rebuild project at milepost 187-197 in Franklin County. "In addition to the obvious environmental benefits, recycling helps keep costs down because we do not have to ship the material away."

It seems somehow poetic that the original Turnpike — that has been serving motorists for almost six decades — will continue to be an integral part of the new, advanced roadway system (albeit buried beneath layers of ultra-modern blacktop). Still, as Heigel pointed out, the original road has endured quite well.

"Actually, the 60-year-old concrete slabs are not in bad shape," said Heigel. "It’s really only the joints that have deteriorated. That’s what you feel — that bump, bump, bump — going down the road."

He attributes the Turnpike’s longevity to ongoing resurfacing and maintenance efforts. "We have been extremely vigilant in resealing the roadway," said Heigel.

In 1954, the original concrete road began to show signs of wear due to a meteoric increase in traffic volume, and so the first re-paving project was begun on a 21-mile stretch east of the Laurel Mountain Tunnel. By the fall of 1962, the entire 160-mile original turnpike had been resurfaced.

Since then, a continuous maintenance program has been in place across the Turnpike in which approximately 10 percent of the roadway is rebuilt each year – and the road is completely renewed every decade.