Carbon Nanotubes at Work

Carbon nanotubes also will figure into two research projects announced in early April by FHWA. The project, under way at Florida State University, seeks to develop technologies to inhibit corrosion for new in-situ materials, and methods to repair or retrofit structures located both above and underwater. The research will utilize carbon nanotubes to develop an on-site spray-based method to develop both a structural capacity enhancement, and a barrier layer for corrosion resistance.

FHWA also issued a cooperative agreement for the University of Minnesota-Duluth to develop new, intelligent, self-sensing concrete pavement that can monitor its own structural health by continuously detecting internal stress level changes of the pavement. In the proposed pavement structure, the concrete will be mixed with carbon nanotubes, the piezoressitive property of which will enable the concrete to detect the changes in the mechanical stress.

Phase I of the proposed work will develop and test a prototype of self-sensing CNT concrete in a lab environment, and Phase II, which will be conducted in partnership of the Minnesota DOT, will fabricate and test the self-sensing concrete in a real but controlled road environment at the Minnesota Road Research Facility just north of Minneapolis.

Commercial Implementation

In the meantime, tried-and-true technologies like GPR are continuing to make their way into the field, but it’s only possible through improved technology.

“There are companies that will conduct a commercial GPR survey, and provide you with information that is based on more than just looking at echoes,” Chase said. “The work on phased array, on synthetic aperture, computer-aided tomography, and storing all this data on a computer and processing it to get information about what’s going on under the surface, all has evolved significantly in the last 15 years. A number of commercially-available systems have the capability of doing this type of signal processing, where it was not the case 15 years ago.”

And much more has transpired over the last decade-and-a-half. “The great thing is that simultaneous technological advances are making things possible today that weren’t possible just 15 years ago,” Chase said. “There have been tremendous advances in battery technology driven by the cell phone and wireless community that are now making it possible to have battery lives that are much longer than before. There also has been a focus on the development of low-power components, again, driven by the wireless technology industry, and they all have benefits for the bridge monitoring community.” v