Physico-mechanical properties of composite concrete, Modified by Nano-carbon

Modern carbon nanofibers (CNF), obtained from polyacrylonitrile (PAN), do not have high tensile strength. It is because there is still no understanding how the electroforming method affects the quality of CNF. This paper investigates a process to obtain high-strength nanofibers with a carbon content of up to 90% by the method of electroforming. The research made it possible to obtain CNF with a diameter of 150-500 nm with unique properties due to our CNF continuous and combined forms, which distinguishes our CNF from existing ones when applied to composite materials. also in this paper, we analyze how to use carbon nanofibers to modify cement materials. We justify the mechanism of strengthening action of carbon nanofibers and their optimum concentrations for a selected concrete mix (0.05% by weight of cement mass). In this study, we demonstrate that it is possible to significantly improve the physical and mechanical properties of concrete (strength increase by more than 110% and the fracture toughness index increase by more than 80%), if we introduce hydrophilic carbon nanofibers together with surfactants. We proved that a synergistic effect occurs if we mix surfactants and carbon nanofibers. We also propose an optimal compositions of complex nanofibers-containing modifiers and surfactants. Finally, we deduced a rational amount of these components to be introduced into a concrete mixture (0.05% by weight of the cconcrete mass). Thus it is established, that our additives can be effectively used to create concrete materials, used in critical building structures.

Keywords:

nanofibers , polyacrylonitrile , electroforming , oxidation , modifier , concretes