Fatigue behavior of the reinforced concrete slab-track

This study quantifies the static and high-cycle fatigue performance of non-prestressed reinforced concrete slab-track panels developed as locally optimized variants of the CRTS III system for high-speed rail. Two full-scale designs were tested: NC1, a uniform 250 mm slab with a tensile reinforcement ratio of 1.584%, and NC2, a tapered 210–250 mm slab with a reinforcement ratio of 1.453%. Three-point bending tests with up to 2 × 1 0 6 sinusoidal load cycles, digital image correlation, and embedded strain measurements were used to monitor crack initiation, stiffness degradation, and deflection. NC1 retained higher stiffness, smaller stabilized crack widths, and lower mid-span deflections, while NC2 developed a more uniform but wider crack pattern and higher curvature. Both designs showed early crack acceleration, and flexural behavior governed failure after fatigue. A calibrated 3D nonlinear finite element model with a plasticity–fracture formulation reproduced load–deflection responses, crack localization, and fatigue degradation with minor post-peak deviations. The results demonstrate a trade-off: thicker, higher-reinforcement slabs improve fatigue resilience and serviceability, whereas tapered, lower-reinforcement slabs reduce material use but require stricter crack-width control. • Comparative full-scale fatigue testing of two optimized reinforced concrete slab-track designs. • NC1 (thicker, higher reinforcement) showed 47% narrower cracks and higher stiffness. • NC2 (tapered, lower reinforcement) achieved 86% of NC1’s capacity with less material. • A calibrated finite element model accurately captured crack localization and fatigue degradation. • Clear design trade-off identified: fatigue resilience (NC1) vs. material efficiency (NC2).