Performance and microstructural characterization of sustainable self-compacting geopolymer concrete with multi-component binders

The extensive use of Ordinary Portland Cement (OPC) in construction contributes significantly to global CO₂ emissions, necessitating sustainable alternatives. This study explores the potential of Self-Compacting Geopolymer Concrete (SCGC) as a green substitute. SCGC formulations incorporate Fly Ash (FA), Ground Granulated Blast Furnace Slag (GGBFS), Rice Husk Ash (RHA), and Micro Silica (MS) as binders, tested with solution-to-binder ratios of 0.5, 0.55, and 0.6. MS partially replaces RHA at 0%, 5%, 10%, and 15%, with fresh and hardened properties evaluated via workability, compressive strength, tensile strength, and flexural strength. Durability was assessed through porosity, sorptivity, Rapid Chloride Permeability (RCPT), and Accelerated Carbonation (ACPT), complemented by Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), Energy Dispersive X-ray (EDX), and X-ray Diffraction (XRD) microstructural analyses. Results showed optimal performance at 15% MS, yielding a compressive strength of 62 MPa and a denser geopolymer matrix. Key phases identified include C/N-A-S-H, mullite, and calcium aluminate silicates, enhancing strength and durability. This research highlights SCGC as a viable, high-performance, and sustainable alternative to conventional concrete, supporting green infrastructure and reducing the environmental impact of the construction industry.