This work analyzed the effect of the addition of single-wall carbon nanotubes (SWCNTs) on mechanical and electrical properties of cement composites through Molecular Dynamic simulations. To model the atomic structure of the Calcium Silicate Hydrates (C-S-H) gel, Tobermorite 11Å was chosen. SWCNTs type Armchair (3,3) incorporated into the tobermorite structure in four different quantities (0.00%, 1.22%, 2.55% and 4.00% by weight of Tobermorite 11Å) were tested through simulations of applied uniaxial pressure, as well as simulations of applied electrical field, to study the effect of the concentration of carbon nanotubes in the cement composite. Results exhibited a higher tensile strength and a higher Young's Modulus for the model Tob-CNT(4.00wt%) with values of 14.27 GPa and 165.46 GPa, respectively, while the model Tob-CNT(2.55wt.%) showed a stronger converse piezoelectric response with a calculated of 8.62 .