Influence of selected parameters on compressive strength of geopolymer produced from ground glass fiber

In this study, ground glass fiber (GGF), manufactured by milling waste glass fiber, was used to produce geopolymer mixtures. The effect of using different alkali content and different combinations of alkali activator solutions on the compressive strength and micro-structure of GGF-based geopolymer mixtures were investigated and compared with fly ash-based geopolymer mixtures. Furthermore, the effect of temperature (from ambient to 110 °C) and duration of heat-curing on the compressive strength and micro-structure of GGF-based geopolymers was studied. Results of this study showed that for all the levels of alkali content, GGF-based geopolymers showed a higher compressive strength in comparison to the fly ash-based specimens; prepared with a same solution and heat-curing method. It was also seen that the strength gain in GGF-based geopolymers does not depend on the presence of sodium silicate in the activator solution; and high compressive strength (as high as 80 MPa) can be achieved by using sodium hydroxide solution alone. The temperature of heat curing was also seen to affect the early-age (i.e. 3-7 days) strength of the GGF-based samples, but had no significant effect on the later-age (i.e. 28-56 days) strength. Finally, it was concluded that GGF has a good potential to be used as a precursor to produce high strength geopolymers even at the low curing temperatures as the ambient temperature (23 °C).