In this study, electrical characteristics of pressure-sensitive carboxyl multi-walled carbon nanotube (MWNT)/cement composites with and without compressive loading were investigated. Experimental results indicate that the carboxyl MWNT/cement composites have both resistance and capacitance characteristics. Capacitance is insensitive to compressive loading, but the charging of the capacitor causes a linear increase in the measured resistance during DC measurement. The reversible pressure-sensitive responses of resistance to compressive loading can be extracted by removing the linear increase component. An AC measurement method can also be used to eliminate the effect of capacitor charging and discharging on the pressure-sensitive responses of carboxyl MWNT/cement composites.
Bibliographical noteFunding Information:
The authors thank the funding supported from the US National Science Foundation (CMMI-0856477), Federal Highway Administration (FHWA) of US Department of Transportation (DTFH61-10-C-00011), the Northland Advanced Transportation Systems Research Laboratory (NATSRL) of the University of Minnesota Duluth, and ITS of the University of Minnesota. This work is also partially supported by National Science Foundation of China (Grant Nos. 50808055 , 51178148 ), the Ministry of Science and Technology of China (Grant No. 2006BAJ03B05 ) and Natural Scientific Research Innovation Foundation in Harbin Institute of Technology (Grant No. HIT. NSRIF. 2009096 ).
- Carboxyl multi-walled carbon nanotube
- Cement-based composites