Investigation of Flow Times of Geopolymer Grouts

warming. In this context, it is known that cement production contributes approximately 7% to global CO2

emissions. Increased construction activity is driving up cement consumption, highlighting the need for

sustainable, environmentally friendly alternative binding materials. Geopolymers are binding materials obtained

by chemically activating waste materials containing silicate and aluminate with suitable alkali activators and can

be considered as an alternative to Portland cement (PC). Studies in the literature show that geopolymers provide

high strength, durability, and acid resistance under suitable conditions. In this study, geopolymer-based grout

mixtures were prepared using waste materials such as fly ash (FA) and silica fume (SF) and evaluated as an

alternative to cement. In the study, geopolymer grout mixtures containing cement, FA, SF, and alkali activator

solution (NaOH and Na2SiO3) (AAS) at different water/binder ratios (w/b = 0.85, 1.05, and 1.25) were prepared,

and their flowability performance was determined using the Marsh funnel test. The experiments were conducted

in accordance with the American Society for Testing and Materials (ASTM) D6910/D6910M-19 standard. The

results showed that increasing the w/b ratio reduced the viscosity of the grout mixtures and decreased the flow

time. Additionally, it was determined that FA and SF additives positively affect fluidity. The flow times of

mixtures containing AAS were found to be lower than those of mixtures containing only cement. The addition of

AAS enhances the effectiveness of geopolymerization, enabling the grouts to acquire suitable fluidity properties

for injection.