Development of Fibre-Reinforced Self-Compacting Geopolymer Concrete with Enhanced Durability Performance

The demand for environmentally responsible construction materials has accelerated research into alternatives to ordinary Portland cement–based concrete. Self-compacting geopolymer concrete (SCGC) has gained attention due to its low carbon footprint and excellent workability; however, its brittle nature, cracking susceptibility, and durability concerns under aggressive environments limit its wider application. This study presents the development of an ambient-cured fibre-reinforced self-compacting geopolymer concrete (FRSCGC) incorporating stainless steel fibres to enhance mechanical performance, dimensional stability, and resistance to chemical attacks. Fly ash and ground granulated blast furnace slag were used as aluminosilicate precursors, while a sodium-based alkaline activator facilitated geopolymerisation at room temperature. The durability performance of SCGC and FRSCGC was evaluated through sulphate resistance, acid resistance, rapid chloride permeability, drying shrinkage, and microstructural investigations. Experimental results demonstrated that the inclusion of stainless steel fibres significantly reduced mass loss, expansion, and permeability while improving compressive strength and ductility. Drying shrinkage was substantially reduced in FRSCGC compared to the control mix, indicating superior dimensional stability. Microstructural observations confirmed effective crack-bridging and a denser interfacial transition zone, contributing to enhanced durability. The outcomes highlight FRSCGC as a sustainable and durable material suitable for infrastructure exposed to aggressive environments.