Study on mechanical and electrical performance of highly dispersible electrostatic self-assembled nanocomposite concrete

Carbon nanotubes (CNTs) and graphene oxide (GO), two nanomaterials with excellent mechanical and electrical performance, are expected to obtain concrete with both high mechanical performance and electrical performance through single-doping and multi-doping. However, the low dispersion performance of both within the concrete resulted in their limited composite effect on concrete. Consequently, to enhance the dispersion performance of CNTs and GO in concrete, and thus realize their objective of "low content, high performance" in concrete, a novel type of electrostatic self-assembled CNTs/GO nanomaterial (CG) was assembled by CNTs and GO in different assembled ratios in this paper. The effects of the assembled ratio and cement pore solution on the dispersion performance of CG were investigated. The effects of the assembled ratio and material content on the mechanical/electrical performance and the composite mechanisms of CG composite concrete were investigated in combination with the results of field emission scanning electron microscopy. The results demonstrate that the CG possesses a three-dimensional reinforced structure comprising GO as the core lamellae and CNTs as the extended scaffolds. This structure enables the dispersion performance of the CG dispersion solution better than that of the CNTs dispersion solution, and unaffected by the cement pore solution. Among them, the absorbances (Abs) of the 6CG dispersion solution and 8CG dispersion solution were enhanced by 26.9 % and 68.7 %, respectively in comparison with CNTs dispersion solution. Furthermore, the Abs of the solutions following the mixing of both CG dispersion solutions with cement pore solution was enhanced by 34.1 % and 23.0 %, respectively, in comparison with that before mixing. The flexural strength of the 0.05 wt% 8CG composite concrete increased by 16.65 %, in comparison with the control group. At a test frequency of 100 kHz, the resistivity of the 0.10 wt% 8CG composite concrete decreased by 18.80 % and the capacitance increased by 29.45 % compared to the control group.