Physical and Microstructure Properties of Geopolymer Nanocomposite Reinforced with Carbon Nanotubes

Abstract

The effect of carbon nanotubes on the physical and microstructure properties of fly ash geopolymer has been investigated in this paper. Fly ash was mixed to carbon nanotubes and sing sodium hydroxide (NaOH) at different concentrations of 10 M 15 M and 20 M, respectively. The ratio of sodium hydroxide to sodium silicate (NaOH : Na2SiO3) of (1: 2) and the ratios of fly ash to carbon nanotubes were 1%, 2%, 3%, 4%, and 5% by weight. Then, tested for physical properties such as compressive strength, bulk density, and porosity and all physical properties were improved by increasing the carbon nanotubes contents, and showed superior physical properties over a pure geopolymer matrix. The phase composition and microstructure of geopolymer nano-composites are also investigated using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscope (SEM) techniques. Results show that the physical properties of geopolymer nano-composites are improved due to addition of carbon nanotubes at curing time of 28 days with concentration of 15 M of sodium hydroxide solution. The optimum 1wt% carbon nanotubes addition exhibited the highest compressive strengths, bulk density and lowers the porosity. The microstructural analysis results indicate that the carbon nanotubes behaves not only as a filler to improve the microstructure, but also as an activator to facilitate the geopolymeric reaction.