self sensing concrete, page-2

G'day riccus.

Good subject. See below for an explanation to help the ball get rolling on this thread.

Normal concrete is not sensitive to applied loads because of its low electrical conductivity. This weakness can be overcome by adding carbon nanotubes, which have a high conductivity (102-104 S/cm). Therefore, if concrete is submitted to compressive forces this will increase the number of contact points between the nanotubes and thus, will lead to a decrease in the resistance of the material. This will then confer to concrete a stress-sensitivity that will enable a stress monitoring of the structures through the measurement of the variations of electrical resistivity. This feature of the carbon nanotubes reinforced structures will be used to continuously monitor normal stresses during service life as well as, exceptional events such as seism, shocks and explosions that generate plastic deformations [11]. Experimental results [12] showed that the fabricated self-sensing CNT/cement composites present sensitive and stable responses to repeated compressive loadings and impulsive loadings, and also have remarkable responses to vehicular loadings. These findings indicate that self-sensing CNT/cement composites have great potential for traffic monitoring.