An investigation on Engineering properties of Self-Compacting Geopolymer Concrete by Taguchi Method

In the present study, due to sustainable development and eco-friendly aims, alkali activated slag and fly ash were used as the geopolymer binder instead of cement in self-compacting concretes. The alkaline solution consisted of sodium hydroxide and sodium silicate solutions. Binder content was between 500-700 kg/m³ and water to binder (W/B) ratio varied from 0.45 to 0.48. Na₂O percentages were in the range of 5 - 7% and three ratios of coarse to fine aggregate (25/75, 30/70, 35/65) were used. Design of experiments was based on orthogonal L9 array of Taguchi methodology. A total of nine main mixes and three validation mixes were prepared. Fresh concrete characteristics and mechanical properties including compressive strength, splitting tensile strength, modulus of elasticity and water absorption were evaluated. The results demonstrated that the binder content and coarse to fine aggregate ratio were the most influential parameters on the mechanical properties. The highest compressive strength, splitting tensile strength and modulus of elasticity were belonging to the mixture with low W/B ratio and higher binder content by 58 MPa, 4.5 MPa and 32 GPa, respectively. Moreover, Taguchi method has a good capability (R²≥0.967) to analyze and predict the mechanical properties of self-compacting geopolymer concrete.