Recently, a road crew from the University of Kentucky’s Transportation Center spent two days testing the strength of the concrete between the 45 and 65-mile markers on I-24. Keith Todd, the public information officer for districts one and two of the Kentucky Department of Highways, said the tests were being conducted because of damage to concrete slabs on the interstate. There have been significant cracks near the 48-mile marker, so the department decided they needed to know the conditions of the longer stretch of roads in order to plan more effectively for future construction.
To collect the necessary data, the Transportation Center’s Tim Scully and Jamie Creech drove slowly down the westbound right lane in a truck with their equipment. Although the typical signs advised drivers to slow, most of did not seem to follow the warning. This was probably because, instead of a construction site, people just saw trucks creeping down the road. Todd said one crewmember told him it was the most dangerous project he had worked on.
In the truck, Scully and Creech operated their equipment independently of each other. Scully was testing the stiffness of the concrete with a device called a falling weight deflectometer, or an FWD, as “most people in the business call it.” The FWD is raised up and hits the concrete at a force anywhere from 4,000 to 27,000 pounds, depending on what number is dialed into the computer. Scully said he set the machine that day at 18 kips, or 18,000 pounds. He administered this test twice every tenth of a mile: once for the midpanel of the slabs and once for the load transfer, where steel joints hold the slabs together. Scully said there are rectangular metal objects known as “baskets” underneath the joints that are meant to push back on the weight of traffic, making the transfer of the load easier on the concrete.
For the rest of this story, read this week's Cadiz Record.