Building a sustainable future: An experimental study on recycled brick waste powder in engineered geopolymer composites

In light of the growing global issue of construction waste management, disposal, and environmental impact, this study uniquely focuses on investigating the viability of recycled brick waste powder (RBWP) as a replacement for conventional industrial wastes like ground granulated blast furnace slag (GGBS) and fly ash (FA) for manufacturing engineered geopolymer composites (EGC). The EGC mixes was prepared by utilizing polyvinyl alcohol (PVA) fiber with a 12 mm length, and 40 micrometers were used. The classes F of FA and GGBS replaced by the RBWP in EGC by 0%, 20%, 40%, 50%, 60%, 80%, and 100%. A total of 14 different EGC mixtures were prepared. The flowability, initial and final setting times, density, compressive strength, direct tensile strength, and tensile stress-strain diagrams of EGC were examined. A microstructural characterization was carried out, involving the use of X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The results indicated that the inclusion of RBWP in the FA-based EGC mixtures resulted in decreasing the flowability in terms of the extra usage of superplasticizer from 0 to 6% and the initial and final set by about 90% and 91%, respectively. Admittedly, there was a significant enhancement observed in the compressive strength, tensile strength, and tensile strain capacity, with improvements of 25%, 29%, and 172%, respectively, when RBWP completely replaced FA. However, the flowability, setting time, density, compressive strength, and tensile strength of the EGC decreased when GGBS was completely replaced by RBWP. However, there was a remarkable improvement in the ultimate tensile strain, which increased by a factor of 11 compared to fully GGBS-EGC. Moreover, the microstructural characterization analysis revealed that the RBWP exhibited effective geopolymerization within the EGC mixtures. These results demonstrate the interesting prospective application of RBWP as an effective replacement for industrial wastes in the production of EGC.