Study on thermal degradation and mechanical recovery characteristics of Portland cement paste incorporating CNT and nano-SiO2

Abstract

In this study, the effect of nano-SiO2(NS) on thermal degradation and mechanical recovery characteristics of cement pastes containing 0.25 wt.% content of Multi-Walled Carbon Nanotubes (MWCNT) exposed to elevated temperature and rehydrated under various conditions was investigated. The cement pastes were replaced with nano-SiO2 in quantities of 0%, 5% and 10% (by weight of cement), respectively. The samples were exposed to the elevated temperatures of 200, 500 and 800 ℃, respectively. After heating, samples were rehydrated under different conditions. The variation in mass loss, bulk density, visual inspection, compressive and splitting tensile strength due to heating and rehydration were determined. In addition, by the mean of X-ray diffraction (XRD), the qualitative analysis of change of hydration product was characterized.