S. Aydın, B. Baradan - Dokuz Eylül University, Izmir, Turkey
The aim of this study is to product a fly ash based binder without Portland cement. Type C fly ash was activated by NaOH with different molar ratios and cured in three different curing conditions (standard, steam and autoclave). Flexural and compressive strength values of mixtures were compared with conventional Portland cement mortars. In the second stage of this study, mechanical properties of fly ash based binders were improved by using silica fume and ground granulated blast furnace slag. Test results showed that the low early strength of FA based geopolymer can be improved by slag replacement and high performance geopolymer mortars can be produced by autoclave curing. Incorporation of fly ash by 50% ground granulated blast furnace slag and 10% silica fume was significantly increased the mechanical properties of autoclaved mortars. Drying shrinkage and swelling of geopolymer mortars were similar to Portland cement mortar. Both steam curing methods were effective in terms of reducing drying shrinkage and swelling of geopolymer mortars.