Effect of multi-walled carbon nanotubes on mechanical properties of high-performance mortar

Abstract

High-performance mortars (HPMs) are very compact handmade composites with high compressive strength and low permeability and flexibility. Because of these properties, HPMs are used in special structural and defensive structures. This paper reports on the influence of functionalised multi-walled carbon nanotubes (MWCNTs) on the impact resistance and compressive and flexural strengths of HPM. The functionalised MWCNTs were characterised using Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). FTIR analysis confirmed the presence of oxygen-containing groups such as hydroxyl and carboxyl on the surface of oxidised MWCNTs. The XRD results revealed a sharp peak at around 2θ = 26° and a broad peak centred at 2θ = 43°, corresponding to the (002) and (100) Bragg reflection planes respectively. The results of tests on reinforced high-performance mortar containing 0·1 %wt MWCNTs show that the impact resistance, compressive strength and flexural strength were 1400%, 25·58% and 2% higher than those of HPM without MWCNTs. Furthermore, scanning electron microscopy test results show that the presence of MWCNTs has a significant effect on the microstructure of HPM.