Performance Evaluation Of Geopolymer Concrete For Railway Superstructure Applications

Fly ash-based blended Geo-Polymer Concrete (GPC) is recognized as a low-carbon concrete with the possibility to replace Ordinary Portland concrete (OPC), due to its better mechanical properties, durability, and environmental impact. In the realm of railway systems, where concrete materials and structures play a vital role, GPC has great potential for the building of various assets. This study explores the durability of GPC for railway superstructures, specifically sleepers and ballast-less tracks, facing diverse environmental challenges. Industrial waste exhausts like fly ash (Class F) and Ground Granulated Blast Furnace Slag (GGBS) are blended as binding material when an alkali activator is used. M60-grade concrete was prepared for conventional OPC and GPC. Evaluation tests include durability under chloride and sulphate attacks, water absorption, and sorptivity. Mixes undergo exposure to different percentages of NaCl, HCl, and H2SO4 solutions between 7-28 days, maintaining an alkaline liquid-to-binder ratio of 2.5, with a 12 Molar concentration of NaOH. The test results revealed that GPC exhibited significantly higher resistance to chloride and sulphate compared to OPC. Additionally, deterioration, density, and compressive strength are examined. A correlation is proposed to identify the compressive strength of OPC and GPC mixes under aggressive media exposure, aligning with prior studies. Overall, GPC proves to be a resilient and durable alternative for railway superstructure construction.