Enhancing the properties of fly ash-based geopolymer concrete using recycled aggregate from waste ceramic electrical insulator

In this study, a recycled waste ceramic electrical insulator (CM) was used as coarse aggregate in geopolymer concrete. The properties of concretes containing CM were compared with those of concretes containing natural coarse aggregate (NA). The variables were concentrations of sodium hydroxide (NH) (10, 15, and 20 M), the ratio of sodium silicate to sodium hydroxide (NS/NH) (1.5, 2.0, and 2.5 by weight), curing temperature (60, 80, and 100 degrees C) and curing period (48, 96, and 144 h). The results showed that the workability, compressive strength, tensile strength, and flexural strength of CM geopolymer concrete were significantly improved consistent with the morphology. An increase in curing temperature and time resulted in an enhanced property of the geopolymer concrete. The mechanical properties of geopolymer concrete satisfied the re-quirements of the standards for structural concrete. Furthermore, the thermal conductivity of CM geopolymer concrete was lower by an average of 21%. These findings confirmed that CM can be used as a sustainable aggregate to produce geopolymer concrete with high compressive strength and low thermal conductivity.