Interface damage analysis of CA mortar layer of the CRTS II ballastless slab track under temperature gradient loads

Damage of interface between the track slab and the cement asphalt (CA) mortar layer under temperature loads will deteriorate mechanical characteristics of the ballastless slab track, so this issue should be paid more attention in service period of the ballastless slab track. This paper established a finite element model of the CRTS II ballastless slab track, which use a cohesive zone model to simulate damage behaviors of the CA mortar layer interface under extreme temperature gradient loads, and the cumulative damage behaviors of the interface with different adhesive strength under cyclic temperature gradient loads. Numerical results show that a ring-shaped interface damage zone appears near the edges of CRTS II ballastless slab track when it is acted by the extreme temperature gradient loads, and the damage causes a redistribution of interface stress, some stress concentration belts are generated on the edges of slab track. Under the cyclic common temperature gradient loads, the interface damage zone of CA mortar layer with normal adhesive strength is relative small, and it does not expand distinctly with cyclic number of temperature loads. For the deteriorated CA mortar interface with a low adhesive strength, the damage zone and the seam area increases quickly with cyclic number of temperature loads, namely, the larger the seam area, the larger the damage expand rate of CA mortar layer.