04 June 2004
04 June 2004
University of Dayton’s (UD) engineering students recently fabricated and tested their "HOT-SPAN" model bridge containing an electrically conductive road surface.
The Hot Span bridge was tested at the SAMPE Super Light-Weight Composite Bridge Building Contest, which is currently in its seventh year. A 110-volt, alternating current was applied to the ends of the bridge to demonstrate the ability to light up a 75-watt light bulb and heat the road surface for winter time de-icing.
The bridge was comprised entirely of glass fibre composite materials, with the exception of carbon nanofibres that were incorporated into the fibre glass road surface, termed "NANO-Sphalt".
The demonstration was performed while the bridge was tested to initial stages of mechanical failure in a three-point bending test. The light bulb remained illuminated throughout the test, thus illustrating the mechanical robustness of carbon nanofibre technology for imparting electrical conductivity to materials that are inherently nonconductive.
The goal of the project was to demonstrate the potential of currently available, affordable nanomaterials and process technologies for fabricating multifunctional composite structures. The project was conducted by University of Dayton electrical engineering student Jon Engelsman and recent chemical engineering graduate Nick Gagliardi. UD-SAMPE Student Chapter Advisor Dr. Don Klosterman served as project advisor. The bridge was constructed at the University of Dayton Research Institute (UDRI).
A key to the success of the project was the ability to uniformly disperse highly conductive carbon nanofibres in the polymer resin used in the composite road surface. Affordable carbon nanofibres, obtained from Applied Science of Cedarville, Ohio, were dispersed in epoxy resin using a nanoparticle dispersion process developed by UDRI and Air Force Research Laboratory researchers at Wright-Patterson Air Force Base (U.S. Patent Application 2003/0039816). This dispersion process is currently being scaled up by UDRI to 10 to 50 pound batch sizes. The process and resulting nanomaterials are currently commercially available from Nanosperse LLC of Akron, Ohio, the exclusive licensee of the dispersion technology.
The SAMPE Super Light-Weight Composite Bridge Building Contest is organized by Dr. Howard Kliger (H.S. Kliger & Associates Inc, Somerset, N.J.), and is a regular annual SAMPE event, growing in popularity and participation since its inception. The goal is to build a lightweight "bridge" that maximizes the ratio of bending strength to bridge weight. The bridges are 24 inches long and have a 4-inch-wide "road surface."
There are different categories based on the types of composite materials used. The HOT-SPAN bridge demonstration was the first of its kind in the SAMPE bridge contest history. This builds on last year's project by UD students, "World's First Carbon Nanofibre Bridge", which targeted structural property improvements.