Facile growth of carbon nanotubes coated with carbon nanoparticles: A potential low-cost hybrid nanoadditive for improved mechanical, electrical, microstructural and crystalline properties of cement mortar matrix

•Cost effective synthesis of RCNT using a petroleum refinery waste has been reported.•Characterization of RCNT confirmed presence of CNTs and CNPs with diameter of 20 nm and 100 nm respectively.•Optimized concentration of 0.50 wt% RCNT in cement matrix produced maximum strength enhancement.•Cement matrix with 0.50 wt% RCNT had improved electrical behavior.•Improved mechanical and electrical behaviors were attributed to good dispersion and crack-bridging effect of RCNT.

A low-cost synthesis of Raw Carbon Nanotubes (RCNT) from petroleum refinery waste is presented. RCNT was incorporated in cement matrix at 0.125%, 0.25%, 0.50% and 1.00% by wt. of cement. Mechanical, electrical, microstructural and crystalline properties of Raw Carbon Nanotube-Cement Nanocomposites (RCNT-CNCs) were evaluated after 28 days, and compared with Pure Carbon Nanotube-Cement Nanocomposites (PCNT-CNCs) and Pure Carbon Nanoparticle-Cement Nanocomposites (PCNP-CNCs). Nanocomposites with 0.50 wt% RCNT, 1.00 wt% PCNP and 0.25 wt% PCNT respectively exhibited rise of 18%, 8% and 37% in compressive strength and 34%, 22% and 57% in flexural strength.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide