Assessing the engineering properties of massive self-compacting geopolymer concretes utilising the Taguchi method

In this article, the potential of employing self-compacting geopolymer concrete in massive elements has been investigated. The main binder consisted of 85% ground granulated blast furnace slag and 15% fly ash. An alkaline solution of sodium hydroxide and sodium silicate was utilised. The effects of four parameters (binder content, water-to-binder [W/B] ratio, Na2O% and coarse-to-fine aggregate [C/F] ratio) on the fresh, mechanical and thermal properties of Massive Self-Compacting Geopolymer Concrete (MSCGC) mixes were evaluated. Taguchi's design of experiments was used to minimise the number of trial mixes. The heat of geopolymerisation of MSCGCs was monitored using a semi-adiabatic chamber and then applied to concrete samples using a temperature match curing system. The maximum compressive and splitting tensile strengths and modulus of elasticity were 62.7 MPa, 5.04 MPa and 33.26 GPa, respectively. Binder content was identified as the most significant parameter affecting the thermal and mechanical properties of the mixtures. The impact of the C/F ratio was greater than the W/B ratio on the thermal characteristics. The results of a numerical analysis reveal that although a higher binder content enhances the mechanical properties of the MSCGCs, it leads to an increased risk of cracking owing to greater heat production.