MoDOT tests concrete panel construction

CHARLESTON -- To motorists driving across it at 60 miles per hour, it is just another stretch of pavement, but to the Missouri Department of Transportation it is an experiment in speeding construction.

"It's approximately 1,000 feet long and it's made up of roughly 100 precast concrete panels," said Eric Krapf, project manager for MoDOT, of the experimental stretch of pavement.

It is comprised of 38-by-10-foot concrete panels that are precast offsite, according to Krapf. In this particular instance, they were cast in Memphis, Tenn.

To construct a road with these panels, a crane at the construction site picks the panels up and positions them on the waiting road bed. "The panels are then tied together with steel cables," Krapf said.

These tensioning strands are run through conduits in the panels to pull them together tightly "so that you have them acting as one unit instead of a bunch of different panels," he explained.

This process allows road reconstruction to be completed and ready for traffic much faster than grading, pouring concrete, and then letting the wet concrete cure, Krapf said.

"The technology is being developed for use in heavily urbanized areas where it becomes uneconomical to go in and have long periods of time where you have lane closures," he said.

This experimental section of road was finished at the end of last year.

"There's only one in the state of Missouri, and it's just west of the Route 105 interchange in Charleston in the northbound lanes of I-57," Krapf said. "It was a pilot project, a research project that we did in conjunction with the Federal Highway Administration, University of Missouri and a consultant."

The project is the third of its kind in the nation with the other two projects having been completed in Texas and California.

This particular location was selected by MoDOT because the pavement needed replacement and that section of highway carries a substantial amount traffic which will allow MoDOT to see how the road section performs.

So far, it is holding up well, Krapf said. "We're going to continue to monitor this," he said.

Monitoring devices were installed by the University of Missouri. "They are also going to continue to monitor these things, see how they perform," Krapf said.

In August, a conference on the process was held which was attended by officials from 11 different transportation departments from New York, Florida, California, Texas and Arkansas along with contractors, representatives from three universities, industry consultants and even representatives from Japan, Krapf said.

"It went very well -- it was very well attended," he said. "I would call it a great success."

Using precast concrete panels is "an innovative way to meet the needs of the taxpayers of Missouri," Krapf said. "I think it went very well."