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

The reduction of CO2 emissions is one of the main challenges of 21st century. The development of new multifunctional construction materials is urgent and compulsory. The privilege mechanical, thermal and electrical behavior of Graphene-Based Materials (GBMs) was found to be potentially extremely efficacious to modify the cementitious materials from the nano- to micro-scale. Thermally and electrically conductive cement nanocomposites with superior mechanical properties and improved durability might be used for inductive wireless charging roads, high speed-train lines, under floor heating, deicing roads and high voltage transmission pipelines. However, presently, the actual effectiveness of a chosen nanocomposite formulation remains unpredictable. 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, mechanical (i.e.flexural and compressive strength) and physical properties (i.e. thermal and electrical conductivity, damping ratio), and permeability (i.e .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) dry powder. 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 a remarkable decreased 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.