Optimization of CWP-Slag Blended Geopolymer Concrete using Taguchi Method

Abstract

This paper aims to optimize the mixture proportions of geopolymer concrete prepared using a binary binder system composed of ceramic waste powder (CWP) and ground granulated blast furnace slag (or simply slag) for superior mechanical performance. The corresponding mixtures were proportioned, analyzed, and optimized by adopting the Taguchi approach. The binder content, CWP replacement rate by slag, alkali-activator solution-to-binder (AAS/B) ratio, sodium silicate-to-sodium hydroxide (SS/SH) ratio, and sodium hydroxide solution molarity were assigned as factors in the design phase. Each factor was characterized by four different levels, resulting in the establishment of an L16 orthogonal array. The target design property was the 28-day cylinder compressive strength. The analysis of variance showed that AAS/B ratio, CWP replacement rate by slag, and SS/SH ratio were key factors affecting the strength in geopolymer concrete, while SH molarity and binder content showed the least contributions. The blended geopolymer made with 40% CWP and 60% slag yielded the optimal compressive strength response with a binder content, AAS/B ratio, SS/SH ratio, and SH solution molarity of 450 kg/m3, 0.5, 1.5, and 10 M, respectively.