With summer comes road construction: warm weather makes it the best season to resurface and repair roadways. All a motorist can do is obey the signs: stop and wait.
But if an innovative researcher named Eric Bescher has his way, the length of closures due to road repairs could be reduced by at least 20%. Drivers would save time, and road construction crews would save a significant amount of money.
Materials science professor Bescher and his team of students from the UCLA Henry Samueli School of Engineering and Applied Science are working to test out a new combination of rapid-hardening cement and embedded computer sensors that monitor the strength of the concrete as it hardens.
The first step in getting traffic up to speed, says Bescher, is using an improved type of rapid-hardening cement that reaches high strength in about twenty minutes. Though the cement has been around for some time, its use on roadways is not yet widespread. The second step, adds Bescher, is ousting antiquated testing methods. That's where Bescher's research comes in. By embedding probes at different levels into the concrete as it is poured, teams can continuously monitor the temperature of the cement at key points as it hardens. The resulting data is downloaded directly into a computer, which monitors the actual temperature and time needed for the cement to harden enough to be safely driven on.
Currently, most road crews use a method called maturity testing that includes making thick sample bars of the concrete and then using special machinery to break the samples mechanically at varying time intervals. The method compares the strength of the concrete to strict standards set by the transportation department. The time required by this method can take hours, delaying the opening of the newly paved area to traffic, which means increased traffic congestion and added irritation for drivers.
According to several studies, including one released recently by the Texas Transportation Institute, based on a conservative estimate of traffic on LA roadways, Bescher's time-saving methods could ultimately save the public as much as $60,000 or more per hour, a figure that does not include the costs incurred by the state for lengthy road closures. If Bescher's method is adopted, the potential financial savings for cities could also be considerable — road crews could complete a larger number of repairs in less time.
The time saved by using the new technology, says Bescher, is startling. "Instead of shutting down freeways for a day or even several days to make repairs, we're talking about only needing to shut down a stretch of roadway for a few hours at night. We believe we can get the appropriate strength and confirm the safety of the roadway within about 30 minutes versus the several hours it now takes."
Bescher and his team are currently working at night throughout the next few months to test their sensor temperature technology on targeted area roadways.
"In future, I hope this technology will be widely available," says Bescher. "It's ultimately a quality of life issue. Motorists will have more time to do more important things than sit in traffic."