Design of Alkali-Activated Ladle Slag Mortar Using Taguchi Method

– This study investigates the feasibility of utilizing ladle furnace slag as a sole binder in alkali-activated mortar. The Taguchi method for design of experiments was used to design, analyze, and optimize the mixture proportions of alkali-activated ladle slag mortars. The five factors considered in the design included ladle slag content (LS), alkali-activator solution-to-binder ratio (AAS/B), sodium silicate-to-sodium hydroxide ratio (SS/SH), sodium hydroxide solution molarity (M), and crushed sand-to-dune sand replacement ratio (CSR). With four design levels, a corresponding L₁₆ orthogonal design matrix was developed. The targeted design criteria were the 7-day compressive and tensile strength, workability, and initial setting time. Analysis of variance results showed that mechanical properties were equally impacted by LS, SS/SH, and CSR. Conversely, the LS, AAS/B, and SS/SH contributed the most to the workability and setting time. Using Taguchi method, three mixes were proportioned based on the analyzed data to optimize each of the design criteria. Validation of the optimized mixes provided evidence of the applicability of the Taguchi method to design alkaliactivated ladle slag mortars with a margin of error of less than 9%.