Enhanced Early Strength and Performances of GGBFS-Based Alkali-Activated Self-Compacting Low Carbon Concrete

Due to the construction industry's dependency on Portland cement, approximately 5-8% of ‎global CO₂ emissions are attributed to its production, which requires an alternative sustainable ‎solution. Recently, alkali-activated materials (AAMs), particularly originating from ground ‎granulated blast-furnace slag (GGBFS), have emerged and presented sustainable alternatives due ‎to their lower ‎carbon footprint and better mechanical properties‏‎. The study focuses on its ‎application to hybrid GGBFS activation utilizing NaOH, Na₂SiO₃, and alkali sulfates in a quest to ‎develop high early strength self-compacting concrete (SCC). ‎This study investigates the ‎potential of SCC incorporating alkali-activated slag (AAS) around 80% Silica Fume (SF) 20% as a complete replacement for ‎Portland cement. Before the test date, samples were prepared under standardized conditions ‎‎and cured in a tank with limewater saturated at 23±1C°.‎ Compressive strength tests were ‎conducted ‎on 150 × 300 mm cylindrical samples at 1, 7, and 28 days. ‎The findings indicate ‎that SCC using AAS could arrive at an early-age compressive strength of around 22 MPa at 1-day age of curing. The hybrid activation system, powered by NaOH, Na₂SiO₃, and alkali sulfates, shows ‎improvements in early-age strength and durability. This system offers a sustainable alternative ‎to conventional cement, reducing CO₂ emissions while maintaining excellent mechanical ‎properties.‎