2.2.2. Concentration of SWCNTs in Mortar Preparation

Ferro et al. [65] found that, when very small quantities of MWCNTs (i.e., 0.025–0.08% wt. cement) were added, the mechanical properties of cement composites materials were noticeably improved, and the quantity of CNTs generally matched with the mass of cement of mixing ratio. Therefore, in this study, three concentrations of SWCNT were used: 0.02 wt%, 0.04 wt%, and 0.06 wt% by the mass of cement. In addition, experiments studying the effect of MWCNTs on mechanical properties of CNTs were also carried out to see the difference of strength between speciments with SWCNTs and MWCNTs. The concentrations of MWCNTs were 0.00 wt%, 0.04 wt%, 0.08 wt%, and 0.12 wt% by the mass of cement.
