Full-scale evaluation of key performance of novel welded connectors in precast airport pavement under fatigue loading

Precast concrete systems, characterized by their environmental sustainability and rapid construction, demonstrate significant potential for expedited airport pavement construction and maintenance. The inherent low thickness-to-size ratio of the thin precast slab leads to localized stress concentrations at joint interfaces, making the configuration and mechanical performance of joints critically govern the long-term serviceability of precast airport pavements. This study introduced two welded connectors optimized for rapid assembly and disassembly. A full-scale experimental structure was developed using ABAQUS, enabling systematic comparative analysis of load transfer efficiency (LTE) degradation, fatigue life, and failure modes across rigid and flexible base. To further validate the operational LTE of both connectors, heavy weight deflectometer (HWD) testing was conducted on the field test section. Results demonstrated that under laboratory static testing, the maximum LTE for connector-A and connector-B were 100 % and 43.7 %, respectively, while field testing yielded average LTE of 79 % and 52 %, indicating significantly superior load transfer performance of connector-A. Fatigue test results indicated that LTE for connector-A under flexible base degraded from 100 % to 20 %, and connector-B degraded from 43.7 % to 15.8 %, whereas rigid base maintained stable LTE for both connectors. Correspondingly, connector-A endured 100,000 cycles without fracture, contrasting with connector-B's failure at 50 000 cycles on rigid base and 6 000 cycles on flexible base. Both connectors failed via rod fracture rather than weld cracking, with fractures localized on the loaded side under low-stiffness bases with poor LTE and shifting to the unloaded side under enhanced LTE conditions. The findings provided actionable guidelines for precast airport pavement joint design, prioritizing the use of connector-A and advocating for high-stiffness base to mitigate LTE degradation and extend service life.