Self-heating and electrical performance of carbon nanotube-enhanced cement composites

Abstract

This work hypothesizes that mixing carbon nanotubes with cement improves the thermal and electrical properties of bulk cement composites. To test this, two different methods of combining cement and dispersed multi-walled carbon nanotubes (MWCNTs) were considered. In the first method, cement composites were produced by adding a dispersion of MWCNTs to cement. In the second, MWCNT-based thin films were spray-coated and integrated with cement to produce cement composites. A third group of specimens was produced using both MWCNT dispersions and MWCNT thin films. The experimental parameters considered were the mixing method, MWCNT concentrations, number of curing days, and voltages applied. Furthermore, field emission scanning electron microscopy revealed that the MWCNTs were evenly dispersed within the composites and formed a percolated network. In addition, X-ray diffraction analysis confirmed that the products formed during hydration of the composites (i.e., C-H and C-S-H) were the same as those generated using ordinary mortar. Upon testing these mortar-based specimens, it was found that the cement composites formed using a combination of MWCNT dispersions and MWCNT-based films exhibited the highest heating performance and lowest electrical resistance. Finally, thermal imaging showed that increased MWCNT concentrations during specimen casting led to a corresponding increase in their surface temperature upon voltage application.