This study presents the first full-scale structural application of CaO-activated GGBFS-based cementless concrete in railway sleepers, demonstrating a significant step toward the practical use of low-carbon binders in demanding infrastructure. Unlike prior work limited to lab-scale or material-level assessments, this research validates the structural and durability performance of cementless concrete under realistic loading and environmental conditions. Full-scale static, dynamic, and fatigue tests were performed. Static testing at both the rail-seat and center regions showed that first crack and ultimate failure loads exceeded design thresholds. Dynamic testing at the railseat demonstrated that crack width loads at 0.05 mm and 0.5 mm surpassed the required limits by approximately 90 % and 54 %, respectively. Fatigue testing confirmed strength retention after 2 million cycles, with post-fatigue failure loads exceeding the standard criteria. Additionally, the material exhibited excellent resistance to freeze-thaw cycles, chloride penetration, and carbonation. These results establish CaO-activated GGBFS concrete as a viable and environmentally beneficial replacement for conventional cement in railway applications.