Optimization of workability and strength of tri-blend geopolymerself-compacting concrete using GGBS, fly ash and silica fume for a sustainable construction practice

The increasing focus on sustainable construction has led to advances in geopolymer concrete due to its eco-friendliness compared with the use of ordinary Portland cement. This research aims on optimizing the workability and mechanical properties of tri-blend geopolymer self-compacting concrete (SCGPC) prepared using Fly ash, Ground granulated blast furnace slag, and Silica fume. Various mix proportions have been prepared by constant 50% fly ash and varying proportions of Ground granulated blast furnace slag from 50% to 25% and Silica Fume from 0% to 25%, while keeping a fixed amount of alkaline activator and binder. The fresh properties of the concrete samples were evaluated through slump flow, T50 slump flow, V-funnel test, and L-box test in accordance with EFNARC guidelines, while hardened properties were determined by means of compressive strength, Split tensile strength and Flexural strength. The results indicate that a mixture of GGBS and silica fumes has a significant effect on both fresh and hardened properties of SCGPC. GGBS with Alkaline solution triggers geopolymerization and has early-age strength due to its calcium content, while silica fume aids in good packing of the particles and matrix densification. The optimized tri-blend combination 50% Fly ash, 40% GGBS and 10% SF displayed better self-compacting ability, superior mechanical properties, and higher micro structural density than in fly ash-based composites systems. Moreover, the usage of industrial by-products helps to eliminate embodied carbon, with emphasis on the environmental advantages brought by SGPC. Finally, tri-blend geopolymer self-compacting concrete appears as a viable and environmentally friendly alternative as construction material.