Enhanced performance of fiber-reinforced engineered geopolymer composites incorporating blast furnace slag and calcined bauxite residue

This study explores sustainable alternatives to conventional cementitious materials by developing engineered geopolymer composites (EGC) incorporating polyethylene (PE) fibers and calcined bauxite residue. The objective is to enhance the reactivity of bauxite residue through calcination, optimize activation mechanisms, and investigate the effects of ground granulated blast furnace slag (GGBFS) replacement on mechanical and durability properties. Evaluations included compressive strength (CS), flexural strength (FS), interfacial bonding strength, freeze-thaw resistance, and sulfate attack. Microstructural analysis employed scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential thermogravimetric analysis (DTG). Results indicate peak reactivity of bauxite residue at 700°C, significant influences of water glass modulus and GGBFS replacement on properties, and weaker microstructures in bauxite mixes dominated by hematite. Analysis of variance (ANOVA) underscores the enhancements in mechanical, durability, thermal, and microstructural performance with calcined bauxite residue and GGBFS in PE fiber-reinforced EGC.