Nov 12, 2009
Smart concrete detects traffic flow
One day in the future, thanks to nanotechnology, a concrete road surface will be "smart" enough to detect vehicle speed, vehicle weight and even its own structural health. Supported by the US National Science Foundation (NSF), researchers from the University of Minnesota Duluth are busy working on the concept and have reported their latest results in the journal Nanotechnology.
To prepare the smart material, the group uses piezoresistive multi-walled carbon nanotubes (CNTs) as an admixture in cement concrete. The electrical resistance of the self-sensing CNT/cement composite is remarkably sensitive to compressive stress, and expresses a linear and reversible piezoresistive response. These findings indicate that this self-sensing nanocomposite cement has great potential for traffic-monitoring applications such as vehicle detection, weighing and speed measurement.
In addition, the team believes that self-sensing concrete could also be used to monitor the stress or deformation of bridges and other civil structures.
There are still some issues that need to be examined before any real-world applications could occur. An important one is to find out the influence of environmental parameters such as temperature and moisture, on the composite's sensing functions.
About the author
Dr Xun Yu is an assistant professor in the Department of Mechanical and Industrial Engineering at the University of Minnesota Duluth. Dr Baoguo Han is a research associate working with Dr Yu, and Dr Eil Kwon is a professor of civil engineering at the same institute. Dr Xun Yu's research group is exploring nanotechnology-based smart materials and structures, sensors, controls and biomedical systems.