Interlayer damage evolution of CRTS III slab track under passenger and freight train loads

To study the interface damage in CRTS III slab tracks under the concurrent interactions of temperature and mixed passenger and freight train loads, a refined fatigue cohesive zone model (F-CZM) considering the stiffness, strength, and energy fracture degradation factors was presented. Utilizing this model, a finite element model (FEM) of the CRTS III slab track was developed. The interface fatigue damage between the track slab and self-compacting concrete (SCC) under various adhesive strengths and mixed operation modes was calculated. The interface characteristic degradation and stress change of door-type steel bars were revealed. Results show that good performance is ensured within the design service life with intact interface adhesion. The interface damage develops from the slab corner to the edge and then into the inner. The diminished interfacial tangential adhesive strength causes two patterns of interfacial damage procession. Enhanced freight train ratio escalates interface damage. During the development of interface damage, the door-type steel bars act as a safety margin.