Structural Assessment of Geopolymer Concrete‐Filled Stainless Steel Tubular Columns

Abstract

Geopolymer concrete (GPC) is a sustainable, cement‐free alternative to ordinary Portland cement concrete (OPC), produced from industrial byproducts activated by alkaline solutions. It provides environmental benefits through reduced CO2 emissions and waste reutilization, while offering high strength, durability, and fire resistance. Stainless steel is widely used in civil construction due to its excellent corrosion resistance, strength, and ductility, ensuring durability and low maintenance in aggressive environments. Its long service life also supports sustainable infrastructure. Combining both materials, this study presents an experimental program on geopolymer concrete‐filled stainless steel tubular (GCFSST) columns. The stainless steel tubes were filled with geopolymer concrete produced using metakaolin (MK) and sodium hydroxide and sodium silicate as activators, with two mix proportions (AS/MK = 0.50 and 0.48), resulting in compressive strengths of 38.69 MPa and 47.25 MPa, respectively. For comparison, stainless steel tubes filled with OPC (47.84 MPa) were also tested. The results showed that GCFSST columns achieved ultimate strengths lower than ordinary concrete‐filled stainless steel tubular columns.