Title:
Effect of Graphene Oxide on the Properties of a Fly Ash-Based Geopolymer Paste Before and After F/T Damage
Author(s):
Zhipeng Li
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/17/2021
Abstract:
This laboratory study demonstrates the beneficial effect of admixing trace amount of graphene oxide to the mechanical properties and durability performance of an environment-friendly fly ash-based geopolymer paste. Such a novel cementitious material was fabricated through the use of chemical activators and graphene oxide to upcycle a class C fly ash into a geopolymer binder. A typical mix proportion of the geopolymer binder features the mass ratios of fly ash: waterglass: lime: triisopropanolamine: sodium sulfate: GO at 100:6:3.6:1.2:1:0.02. The compression strength, splitting tensile strength, water absorption, and gas permeability of this nano-modified paste and its none-modified counterpart were tested before and after F/T cycles, to clarify the effect of GO on the macroscopic properties of this geopolymer paste. Two curing regimes were investigated: ambient temperature and and 60 degree C. We employed advanced tools such as scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), 29Si and 27Al Magnetic Resonance (NMR) to shed light on the mechanistic role of GO both during geopolymer hydration and during F/T cycling. The Ca, Si, Al contents and the Ca/Si, Al/Si, Ca/(Al + Si) mole ratios, obtained from energy-dispersive X-ray (EDX) spectroscopy, were statistically compared to elucidate the effects of GO on the hydration products of the geopolymer binder and their F/T durability.