Using the Taguchi method to optimize the compressive strength of geopolymer mortars

This paper presents the use of the Taguchi method to optimize the compressive strength of geopolymer mortars. The geopolymer was produced from fly ash as a prime material and ordinary Portland cement (OPC) as additive. Fly ash was partially replaced with OPC in the geopolymer mixtures to enhance the compressive strength. The dosage of OPC, the concentration of sodium hydroxide solution (SH), and the curing temperature were considered as the influencing factors on the compressive strength of geopolymer mortars. Three levels of each factor were chosen to carry out this research. As a result, the orthogonal array L9 of the Taguchi method was used to design the experiments. The results of the experiments were analyzed by the signal to ratio (SNR) and the analysis of variance (ANOVA). This analysis has revealed that the least significant factor in terms of strength contribution is the dosage of OPC content, whereas the curing temperature is the most important factor in terms of strength contribution. This research shows that the optimized value of 7-day compressive strength was obtained in the mixture containing 20% of OPC that was prepared by SH of 12 M concentration and cured at 100oC. In addition, the geopolymer mortar produced by 30% of OPC and SH of 12 M concentration and cured at 100oC gained the maximum compressive strength at 28-day age. (C) 2020 The Authors. Published by IASE.