Bond–slip behavior between steel rebar and glass sand concrete using distributed optical fiber sensing

Abstract To alleviate the shortage of natural sand resources and enhance the resource utilization of waste glass, this study investigates the effect of partially replacing natural river sand with ground waste glass sand on the bond performance of the steel–concrete interface. Pull‐out specimens were designed with varying glass sand replacement ratios (0%, 10%, 30%, and 50%) and bond lengths (3d, 5d). Distributed optical fiber sensors were employed to monitor the strain distribution and its evolution at the interface. The mechanism through which glass sand influences bond performance was explored by comprehensively analyzing the failure modes, bond strength, slip, and strain characteristics. The results showed that: (1) specimens with a longer bond length (5d) and higher glass sand content were more prone to splitting failure, primarily because the circumferential tensile stress exceeded the concrete's tensile strength; (2) for a 3d bond length, the specimen with 30% glass sand content achieved the highest bond strength (calculated as the average shear stress over the nominal bonded area) of 38.18 MPa, whereas for a 5d bond length, the 10% replacement ratio was most effective (24.47 MPa); (3) except for the 10% replacement group, specimens with a 3d bond length generally exhibited higher bond strength than those with a 5d bond length, indicating that bond performance is not linearly positively correlated with bond length; (4) the bonding performance significantly decreased at high glass sand content (50%) due to the weakening of the interfacial transition zone, potential alkali‐silica reaction, and grading imbalance. This study demonstrates that an appropriate amount of glass sand (10%–30%) can effectively improve the interfacial properties under specific bonding conditions, providing theoretical support for the high‐value utilization of waste glass resources and the design of green concrete.