The influence of synthesis routes and curing time on the mechanical and microstructure properties of class C fly ash geopolymers

Abstract

The main objective of this study is to investigate the influence of synthesis routes and curing time on the mechanical and microstructure properties of geopolymers made from class C fly ash. Geopolymers were produced by means of alkali activation method varying the synthesis routes as well as curing time from 2, 4 and 6 hours. The resulting samples were stored 28 days before conducting any measurement. The mechanical properties of geopolymers were examined through compressive and flexural strength measurements. The microstructure properties of the starting and resulting materials were studied by means of x-ray diffraction (XRD) and Scanning Electron Microscope (SEM) coupled with Energy Dispersive Spectrometer (EDS). The results showed that both synthesis routes and curing time affecting the attainable of compressive and flexural strength as well as the microstructure of geopolymers. It was also found that the availability of water and curing time are essential in the production of sodium aluminum silicate which act as the main binder of geopolymers.