Investigation on preparation and multifunctionality of reduced graphene oxide cement mortar.

• A new avenue to prepare rGO suspension with excellent comprehensive was developed. • The mechanical and functional properties of samples were significantly improved. • The percolation threshold of rGO was determined by comparing different performance. • The functional mechanism of rGO to mortar was analyzed by comparing different model. For modern concrete materials and structures, how to realize the multifunctional application is still a challenge. The introduction of functional components into concrete materials is the most effective method. The present study successfully develops a new avenue to prepare rGO suspension with excellent dispersibility and stability through the combination of dispersant and ultrasonic pre-dispersion. This rGO suspension is added to the cement-based material, resulting in the improvement of mechanical and functional properties. The compressive and flexural strength of mortar are increased by 45% and 50% at 3 days, respectively. Meanwhile the hydration heat and pore structure are improved up to doping 2.00 wt% rGO. Moreover, the resistivity and thermal conductivity of mortar are decreased by 45% and increased by 23%, while the electromagnetic shielding effectiveness of cement paste is increased by 45%. In addition, the pressure-sensitive property of mortar increases first and then decreases with the increases of rGO content, wherein the largest stress and strain sensitivity coefficient can reach up to 1.28%/MPa and 147.80 with 2.00 wt% rGO. These results demonstrate that doping rGO is a promising approach to the improvement of the functionality of cement-based materials resulting from the doping rGO is attributed to, the formation of a conductive network structure with the continuous phase in the cement matrix when rGO content reached percolation threshold. [ABSTRACT FROM AUTHOR]