Deformation characteristics and interfacial damage of CRTS II slab track joints under operating temperature conditions

• Annual extreme temperature range of CRTS II slab track is −1.4 to 49.8 °C, with vertical temperature gradients up to 30.15 °C/m. • High temperatures cause vertical joint deformation up to 0.828 mm, while low temperatures induce joint separation of 0.9–1.0 mm. • Interfacial damage is primarily driven by elevated temperatures, with damage area ratio reaching 95% and debonding ratio up to 84% in summer. • The thermo-mechanical coupling model provides a basis for predicting joint damage and guiding deformation control in CRTS II slab track.