Optimizing Physical and Mechanical Properties of Metakaolin and Calcium Carbide Residue – Geopolymer Concrete Using the Taguchi Method

The construction industry is seeking alternative sustainable materials for construction due to the increased demand on the conventional construction materials. Investigations into environmentally friendly binders, most predominantly geopolymer, have intensified in the past few years. The Taguchi method is used in this present study to optimize the properties of geopolymer concrete mix. Three factors at 2 levels each, that is, liquid-to-binder ratio (0.8 and 0.6), coarse aggregate sizes (14 mm and 16 mm) and curing regime (ambient temperature with and without wet hessian mat) were considered to produce four concrete mixes. The workability, density, compressive strength and flexural strengths of the geopolymer concretes were evaluated. The slump values of the fresh geopolymer concrete were classified as S1 and S2. The optimum geopolymer concrete that produced the highest density, compressive strength and flexural strength was obtained at mix T3 (liquid-to-binder ratio of 0.6, 16 mm coarse aggregate and cured with wet hessian mat). Based on the signal-to-noise ratio, the size of the coarse aggregate had the most influence on the density. The liquid-to-binder ratio had the most impact on the compressive and flexural strengths.