Investigation on Mechanical, Microstructural, and Sustainability Analysis of Ternary Blend Alkali-Activated Concrete

Efforts to enrich concrete performance and reduce environmental impact drive the development of alkali-activated concrete (AAC), which eliminates the need for cement. This study investigates the effect of fly ash (FA) and rice husk ash (RHA) on ground granulated blast furnace slag (GGBS) based AAC to produce sustainable concrete. Different AAC mixes were developed using a constant amount of GGBS (50%), with the remaining 50% replaced by FA (50% to 0%) and RHA (0% to 50%) using a 12 M NaOH solution. The test results show that fresh AAC achieves a higher slump using lower RHA with higher FA content. The unit weight of AAC is reduced when using a higher RHA with lower FA content. The research shows that using 40% FA with 10% RHA exhibits superior mechanical properties. Linear regression analysis examines the correlation between compressive strength and both destructive and non-destructive parameters. Analysis of variance (ANOVA) was used to assess the influence of selected variables (binder and curing age) on the mechanical strength of ternary blend AAC. Microstructural analysis (SEM and FTIR) reveals mechanisms that enhance the strength of the ternary blend AAC. This study also emphasizes the cost-effectiveness and eco-friendliness of ternary blend AAC, utilizing industrial and agricultural waste, and assesses its environmental impact.