Cement Pastes and Mortars Containing Nitrogen-Doped and Oxygen-Functionalized Multiwalled Carbon Nanotubes

Figure 11

(a) Concrete mixing machine of 0.5 m³ capacity, (b) cylindrical metallic mold of 10 cm in height and 5 cm in diameter, (c) pouring molds according to the ASTM standard, and (d) cylinders after curing time (without nanotubes (left side) and with carbon nanotubes (right side)). The cylinder concrete with carbon nanotubes exhibits a dark gray color, suggesting that there is a good dispersion of the carbon nanotubes within the mortar matrix. (e) and (f) Universal testing machine (5-ton capacity) used for the compressive strength measurements.