Effect of bio-additives on physico-chemical properties of fly ash-ground granulated blast furnace slag based self cured geopolymer mortars.

Heat curing catalyzed the geopolymerization reaction in geopolymers whereas the practical challenges in applying heat curing process limited the applications of geopolymers to precast elements alone. Bio-additives inclusion could facilitate ambient temperature curing that lead to environment friendly self cured geopolymers. Natural sugars (molasses/palm jaggery/honey) and terminalia chebula were used as bio-additives in fly ash (FA) and ground granulated blast furnace slag (GGBS) based geopolymer mortars. X-ray diffraction (XRD), Fourier transform infrared spectral (FTIR), thermogravimetric (TG/DTG) and scanning electron microscopic (SEM) studies were used for the characterization for all geopolymer mortar samples. Physico-chemical test results of bio-additives added FA-GGBS based self cured geopolymer mortar samples showed XRD peaks at 2θ = 20°, 26°, 39°, 48°, 66° and 75°, FTIR bands at 3430, 2922, 1390, 1270, 1120 and 881cm-1, DTG peaks at 120 °C, 126 °C and 134 °C that led to the conclusion that development of differences in geopolymer reaction products, intense structural reorganization leading to stable geopolymer matrix and more ordered geopolymer gels. Further SEM observations revealed compact and dense microstructure development in bio-additives added FA-GGBS based self cured geopolymer mortar samples.