Thermo-mechanical coupling effects and fatigue life of precast concrete pavement

Clarifying the mechanical performance and fatigue failure mechanisms of precast concrete pavements under coupled thermo-mechanical loading is of practical significance. This study adopted an integrated framework combining numerical simulation, theoretical analysis, and field testing to evaluate solid and hollow slabs. Based on ABAQUS and the Miner’s rule, fatigue damage values obtained using the coupling and superposition methods were quantitatively compared. The stress responses and fatigue lives of the pavement structures were further analyzed under different load positions, temperature gradients, and base types. Results demonstrated that hollow slabs exhibited a more uniform stress distribution on the top surface due to void-induced stress diffusion, while developing higher flexural tensile stresses under sustained thermo-mechanical coupling. The coupling method yielded more reliable results than the superposition approach. Fatigue damage was more severe under positive temperature gradients, with solid slabs showing pronounced sensitivity, as the fatigue damage increased by a factor of 8.86 × 10¹¹ when the temperature gradient rose from −90°C/m to 90°C/m. Under positive gradients, hollow slabs were more susceptible to damage at the mid-edge of longitudinal joints, whereas slab corners became critical under negative temperature gradients. The base type exerted a greater influence on hollow slabs, and under high temperature gradients, pavements with cement-stabilized bases exhibited fatigue damage magnified by up to 4903 times. Field test data validated the numerical results, and the mechanical responses under three loading conditions were compared, providing a basis for structural optimization and durability-oriented design of precast concrete pavements.