Deterioration in the microstructure of metakaolin-based geopolymers in marine environment

Abstract

In this research, metakaolin-based geopolymers were synthesized to study their deterioration in marine environment. The geopolymers were exposed in air, seawater, dry-wet and heat-cool cycles of seawater for 30, 60 and 90 days. The mechanical property of the geopolymers was characterized through compressive strength measurements, and their microstructures were measured by X-ray diffraction (XRD), scanning electron microscope (SEM) and nuclear magnetic resonance (NMR) apparatus. It was found that seawater environment inhibited the geopolymerization reactions, so that a low amount of tetrahedral silicon of Q4(4Al), Q4(3Al) and Q4(2Al) were formed.