Effect of ferrochrome ash based solid activator on performance of one-part alkali-activated self-compacting concrete mixes

Abstract Utilizing industrial by-products for the production of alkali-activated concrete has gained attention as one of the sustainable solutions to mitigate the environmental impacts of improper waste disposal. This study evaluates the strength and durability of ferrochrome ash-based One-Part Alkali-Activated Self-Compacting Concrete (OPAASCC) mixes. The mixes incorporate industrial by-products, including Ground Granulated Blast Furnace Slag (GGBFS) as a binder and Ferrochrome Ash (FCA) with anhydrous sodium metasilicate as a solid activator. A Taguchi L-9 orthogonal array was employed to optimize the experimental process, minimizing testing efforts. The study assessed fresh and hardened state properties, including compressive strength, split tensile strength, and modulus of elasticity (MOE) of the OPAASCC. Additionally, the microstructure and sustainability parameters were assessed. The experimental investigations on fresh concrete exhibited flow values between 700 and 750 mm, while hardened concrete properties, namely, compressive strengths of 50–70 MPa, flexural strengths of 4–5 MPa, and split tensile strengths of 2–3 MPa. The MOE ranged from 30 to 32 GPa, and Ultrasonic Pulse Velocity (UPV) values exceeded 4.5 km/s, indicating good material integrity. The microstructural analysis using SEM and XRD provided insights into the presence of material-dense composition and crystalline phases, namely, quartz, calcite, and hydrocalcite, alongside the gel phases, supporting the microstructural densification and bonding characteristics in the produced concrete mixes. Additionally, sustainability analysis showed lower embodied energy and carbon emissions compared to conventional concrete. The findings confirm the feasibility of producing self-compacting alkali-activated concrete, achieving desirable performance while supporting sustainable construction practices.