Rheological behavior of geopolymer dope solution activated by alkaline activator at different temperature

Abstract Typically, the geopolymer has a semi-crystalline structure and is amorphous in form. The structural backbone of the geopolymer theoretically relies on aluminosilicate (–Si–O–Al–O‒) ₙ sources, which are adequately found in nontoxic bio-sources. Sugarcane bagasse ash (SCBA) is rich in carbon and (‒Si–O–Al–O‒) ₙ and is widely available as a nontoxic biowaste material. Therefore, in this study, without any additives, the SCBA was used as a base intermediate for geopolymer synthesis. This study involved preparing alkaline activators (AAs) at temperatures ranging from 5 to 60°C. Later, the study’s purpose was to investigate the influence of these AAs on the rheological properties of geopolymer dope solutions. The apparent viscosity and shear stress behavior of the 30 and 50% AA solutions made at 5 and 60°C were higher than those of the ambient circumstances (AA and water ambient conditions). A solution with a 50% sodium hydroxide (NaOH) content yields comparable outcomes. The findings show that a 50% NaOH solution demonstrates higher viscosity and shear stress compared to a 30% NaOH solution. Geopolymer dope solutions also showed the same results. The viscous geopolymer solution results from the formation of a rigid aluminosilicate oligomer and monomer network during geopolymerization. The geopolymer dope solution, prepared under different conditions, showed significant changes in its rheological characteristics. Changes in the processing conditions of geopolymer dopes revealed some significant reactivity in the geopolymerization process, which most likely led to the formation of product clusters. The modified Bingham model and the Herschel–Bulkley model are suitable for evaluating the rheological behavior of the SCBA geopolymer dope solution.