## 1 Introduction
[PERSON] et al. [20] analyzed the heating properties of cement composites with the CNT concentration as a parameter. The CNT concentrations applied were 0.3, 0.6, 1.0, and 2.0 wt% of the cement weight, and the composite dimensions were 50 \(\times\) 50 \(\times\) 50 mm. For the composite with 2.0 wt% CNT, the heating value increased by 67.8 \({}^{\circ}\)C when 10 V was applied, and the heating property improved as the CNT concentration increased. [PERSON] et al. [21] evaluated the electrical conductivities of various cement composites mixed with MWCNTs. The types of cement composites included cement paste, mortar, and concrete, and the MWCNT concentration was within the range of 0.0-1.0 wt% with respect to the cement weight. The experimental results showed that when the same concentration was applied, the cement paste showed the highest electrical conductivity, followed by mortar and concrete. [PERSON] et al. [22] investigated the thermal properties of cement composites using MWCNTs, with the MWCNT mixing method and the MWCNT concentration as parameters. The MWCNT mixing methods included sand coating and aqueous solution mixing. The MWCNT concentrations were 0.125 wt% and 0.25 wt% of the cement weight. The experimental results showed that the sand-coating method exhibited a heating characteristic that was twice as high as that of the aqueous-solution-mixing method, and it increased with increasing MWCNT concentration. Consequently, CNT networks were formed inside the composites, thereby improving their thermal properties. [PERSON] et al. [23] studied the filling rate of grout in which different CNTs were mixed. The specimen dimensions were 40 \(\times\) 40 \(\times\) 160 mm, and the parameters were CNT type, CNT concentration, and grout filling rate. The experiments were conducted using CNT types of single-walled carbon nanotubes (SWCNTs) and MWCNTs, concentrations of 0.1 wt% and 0.2 wt% with respect to the cement weight, and filling rates of 50% and 100%. The results showed that the mixing of SWCNTs produced better heating properties than those obtained when MWCNTs were mixed at the same concentration. When MWCNTs were mixed, the heating property declined with the filling rate, and the positions of the pores were confirmed visually through thermal imaging analysis. However, when SWCNTs were mixed, it was difficult to confirm the position of the pores visually because the current tended to concentrate at the positive (+) pole. Regarding damage detection research, [PERSON] et al. [24] fabricated MWCNT-cement composites with water content as a parameter and examined the piezoresistivity. The piezoresistivity increased with the water content but decreased when the water content exceeded 3.3%. [PERSON] et al. [25] examined strain-sensing properties by mixing carbon nanofibers (CNFs) with cement. The specimen dimensions were 40 \(\times\) 40 \(\times\) 160 mm, and the parameters were the CNF concentration with respect to the cement weight and curing time. The test results showed that the strain-sensing properties increased with increasing CNF concentration. The strain-sensing properties were not observed after 7 d of curing; however, the strain-sensing properties could be verified after 28 d of curing. [PERSON] and [PERSON] et al. [26] fabricated composites in which MWCNTs and CNFs were mixed and examined their electrical properties and piezoresistive sensitivity. For the resistance property experiment, four electrodes were used with a water-cement ratio of 30%. The experimental parameters were the MWCNT CNF concentrations with respect to the cement weight. According to the experimental results, the composite mixed with 0.1 wt% CNT and CNF showed the lowest resistance and the highest piezoresistive sensitivity, respectively. [PERSON] et al. [27] examined strain and damage detection by fabricating cement composites mixed with CNTs and CNFs with respect to the cement weight. They conducted three-point bending tests with the mixing concentration fixed at 0.6 wt%.