Valorization of Sugarcane Bagasse Ash and Jackfruit Leaf Ash in Sustainable Geopolymer Binders: Performance and Microstructural Characteristics

The mounting requirement for sustainable construction materials has augmented the development of geopolymer binders incorporating agricultural wastes. Unlike the previous studies on individual agricultural ashes, this study investigates the viability of combined use of sugarcane bagasse ash (SCBA) and jackfruit leaf ash (JLA) in fly ash-ground granulated blast furnace slag (GGBFS)-based geopolymer binders under ambient curing conditions. Five mixtures with varying proportions of SCBA and JLA were evaluated for their fresh (flow, setting time, fresh density and rise in temperature), hardened (compressive strength and flexural strength) and microstructural characteristics (FESEM-EDS, XRD, FTIR and TG/DTG analyses). The incorporation of 10% SCBA and 10% JLA of the total binder (M3 mixture) was found to produce best performing performance, resulting in a maximum 28-day compressive strength of 64.83 MPa and flexural strength of 7.25 MPa, corresponding to increments of 36.5% and 73.0%, respectively, over the control mix. The formation of a dense reaction matrix along with enhanced geopolymerization and thermal characteristics were also observed for the best performing mixture through microstructural studies. The outcome of this investigation reveals that the utilization of agricultural ashes (SCBA and JLA) can be an efficient supplementary aluminosilicate precursor to develop high-performance geopolymer binders.