INFLUENCE OF SODIUM LIGNOSULPHONATE ON WORKABILITY AND STRENGTH DEVELOPMENT IN GGBS-BASED GEOPOLYMER CONCRETE

Abstract

This study investigates the use of sodium lignosulphonate (NaLS), an eco-friendly lignin-based admixture, to enhance the workability and strength of M30-grade GGBS-based geopolymer concrete (GPC) produced under ambient conditions. The experimental program involved mixes containing GGBS (413.79 kg/m³), fine and coarse aggregates, alkaline activators (sodium hydroxide and sodium silicate), and varying NaLS dosages (0–3% by binder weight). Results showed that adding NaLS significantly improved workability and mechanical properties, with an optimum performance at 2% dosage—slump increasing from 50 mm to 98 mm, compressive strength from 34.0 MPa to 43.5 MPa, split tensile strength to 4.22 MPa, and flexural strength to 5.85 MPa. Beyond 2%, a slight reduction in performance occurred due to excess air entrainment. The study concludes that 2% NaLS optimally enhances the microstructural density, bonding, and overall performance of GGBS-based GPC, establishing it as a sustainable, cost-effective solution for low-carbon concrete development in ambient curing environments.