High performance cementitious nanocomposites: The effectiveness of nano-Graphite (nG).

• Nano-Graphite cement composites are high-performance multifunctional materials. • Smooth workability loss of the fresh admixtures. • Improved density and mechanical strength. • Enhanced damping, electrical and thermal conductivity at the lowest dosage. • Reduced water permeability and chloride penetration. In this study an extensive experimental campaign has been conducted on mortars modified with nano-Graphite (nG) aimed to assess the properties of the resulting nanocomposites in terms of density, microstructure, flexural and compressive strength, damping ratio, thermal and electrical conductivity. Permeability properties were also investigated in terms of initial surface absorption, water contact angle, volume of permeable voids and chloride ion diffusion. Premixed mortars have been modified with different dosages of commercial nG, i.e. 0.01%, 0.1%, or 0.2% by weight of cement. The rheological behavior of the fresh admixtures has been investigated. Specimens were casted in bars and hardened in water for 7, 14 or 28 days. At 28 days all samples showed enhanced density (i.e. up to 16%) and mechanical properties (i.e. up to 30%) combined to remarkable decreased overall permeability. The lowest dosage of nG (i.e. 0.01% by weight of cement) resulted in cement nanocomposites with the highest increase in damping ratio, electrical and thermal conductivity, 68%, 30% and 55%, respectively. [ABSTRACT FROM AUTHOR]