## 4 Conclusions  
From the investigation of the effects of MWCNT properties on dispersion in cementitious composites, the following findings and conclusions were obtained:  
1. The heat of hydration decreased with an increase in the addition ratio of the MWCNTs because retardation occurred, due to an excessive amount of the chemical admixture. In addition, as the amount of MWCNTs increased, the amount of the chemical admixture increased, because the powder volume increased in the specimen. On the other hand, the liquid MWCNT showed further improvement in workability compared with the powder MWCNT, thus reducing the amount of the chemical admixture, and the hydration delay was not as great as that in the powder MWCNT. 2. The heat flow decreased slightly with the addition of MWCNTs, but the degree of the decrease was not significant. The MWCNTs exhibited no chemical reactions in the composites. Therefore, it was concluded that the decrease in the mechanical performance of the cementitious composite was not due to the chemical reaction, but due to the physical properties. In particular, it was due to the MWCNT agglomeration caused by van der Waals forces. 3. The compressive strength tended to decrease as MWCNTs were added. In particular, the powder type showed a greater reduction than the liquid type, and it was found that the MWCNTs did not obtain the micro-filler effect in the mixtures, but rather acted as a strength reduction factor. 4. The porosity analysis indicated that the porosity increased as MWCNTs were added, because the MWCNT agglomeration occurred due to failure to secure uniform dispersion in the cementitious composite. Thus, it existed in the form of large capillary pores, which resulted in an increase in the porosity, leading to a decrease in compressive strength. However, when the liquid MWCNT was added, the porosity further decreased compared with the powder type, which implies that the liquid type was advantageous in terms of dispersibility. Figure 13: Electrical resistance values according to measurement distance. Through Raman spectroscopy analysis, it was revealed that the MWCNTs showed G bands (1350 cm\({}^{-1}\)) in their Raman spectra of graphite. This confirmed the presence or absence of MWCNTs in the composite, and the strength of the peak was highest in the liquid type of MWCNTs, presenting more homogeneous dispersion than the powder MWCNT. 6. In the SEM analysis, agglomeration was clearly observed in the powder MWCNT, and the form of a skein of thread existed. It failed to disperse as it separated from the hydrates in the composite, which resulted in a decrease in strength, due to the presence of pores. However, the liquid MWCNT was relatively well dispersed in the overall zones. 7. The electrical resistance value decreased as the addition ratio of MWCNTs increased. The electrical conductivity also increased and was expected to help achieve self-sensing abilities. In relation to the degree of dispersion, according to the types of MWCNTs, the liquid type was found to be superior to the powder type. It can be confirmed that improvement in the mechanical performance of cement composites incorporating MWCNTs is determined by the degree of dispersion, and it is appropriate to use liquid MWCNTs in all areas, including workability, hydration performance, and the compressive strength of the composite. However, when the liquid MWCNT was used, the composites turned black in color. This problem requires further examination. In addition, it is necessary to address the limitations of mass production technology for dispersion and the limits of the current technology capable of dispersing the powder MWCNT up to 7%. Conceptualization, G.-C.L. and Y.K. ; methodology, G.-C.L. ; validation, G.-C.L., Y.K., and S.H. ; formal analysis, G.-C.L. and S.H. ; investigation, G.-C.L. and S.H. ; resources, G.-C.L. ; data curation, G.-C.L. and Y.K. ; writing--original draft preparation, G.-C.L., Y.K., and S.H. ; writing--review and editing, S.H. ; visualization, S.H. ; supervision, G.-C.L. and S.H.