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 combined with cement to produce cement composites. A third group of specimens was produced using both MWCNT dispersions and MWCNT film-coated. 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. Additionally, 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 dispersion 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.

Damage Detection of Carbon Nanotube Cementitious Composites Using Thermal and Electrical Resistance Properties

“…As shown in Figure 4a, this was achieved by connecting the positive and negative poles of a DC power supply (EX-200) to the stainless-steel meshes inserted in the composites. A voltage of 60 V was supplied to each specimen for 60 min, which was selected because the highest temperature variation occurred at 60 V in the composites mixed with MWCNTs [34]. The temperatures of the composites generated by the applied voltage were measured by connecting the thermocouple to a static data logger (TDS-303).…”

Developments and Applications of Carbon Nanotube Reinforced Cement-Based Composites as Functional Building Materials

“…The self-sensing ability of concrete is achieved by a change in the conductive network of the conductive material inside the concrete (Al-Dahawi et al, 2016a;Al-Dahawi et al, 2016b;Al-Dahawi et al, 2017;Yıldırım et al, 2018;Demircilioğlu et al, 2019;Yıldırım et al, 2020). Smart concrete is developed by adding carbon nanotube (Xing et al, 2016;Al-Dahawi et al, 2017;Gupta et al, 2017;Yoo et al, 2017;Yıldırım et al, 2018;Lee et al, 2020;Yıldırım et al, 2020), carbon fibers (Al-Dahawi et al, 2017;Yıldırım et al, 2018;Yıldırım et al, 2020), steel fibers (Le and Kim, 2017;Demircilioglu et al, 2020;Le and Kim, 2020), graphite nanofibers (Yoo et al, 2017), graphene (Al-Dahawi et al, 2016a;Al-Dahawi et al, 2016b;Al-Dahawi et al, 2017;Yoo et al, 2017;Birgin et al, 2020;Wang et al, 2020), nickel or hybrid materials (Azhari and Banthia, 2012;Konsta-Gdoutos and Aza, 2014) and other functional fillers. The research on CNT reinforced self-sensing cement-based materials is the most concentrated.…”

Effect of Carbon Nanotube Size on Electrical Properties of Cement Mortar under Different Temperatures and Water Content

“…Yoo et al [23] found that MWCNTs had a better enhancement effect on the electrical conductivity of cement paste than graphite nanofibers (GNF) and graphene (G), and the fluidity of the composite had an effect on the resistivity of the material. Lee et al [24] found that the simultaneous addition of dispersed MWCNTs solution and MWCNTs base film to cement composites was able to better enhance the heating properties of the cement paste and obtain the lowest resistance. Cerro-Prada et al [25] studied the effect of four different mass fractions of MWCNTs on the strength and electrical properties of cement mortars.…”