Study on the Mechanical Properties of Door-Shaped Rebar of a CRTS III Slab Track Under Temperature Load

CRTS III (China Railway Track System) slab track is a typical multi-layer composite structure. Door-shaped rebar is an important connecting component. Studying its service characteristics is crucial for disease prevention and control. To investigate the mechanical properties of door-shaped rebar under multi-factor coupling, a three-dimensional finite element model was developed and validated with full-scale tests. Then, considering the initial defects of self-compacting concrete (SCC), interlayer cracks and other damages, the mechanical properties of door-shaped rebar of a CRTS III slab track under temperature load were studied. The results show that under the action of an extreme temperature gradient, the maximum vertical displacement of the track slab occurs in the middle and corner positions of the slab with the positive temperature gradient, with displacement values of 0.87 mm and -0.99 mm respectively. Under positive and negative temperature gradients, the stress of the door-shaped rebar at the interface between the track slab and the SCC layer is 12.9 MPa and 16.5 MPa, respectively. When considering the conditions of the SCC slurry layer, the stress of the door-shaped rebar in the SCC layer under the action of a temperature gradient is generally in an increasing state. When there is a crack at the interface of the SCC layer, the stress of the door-shaped rebar unit in the crack area changes significantly, and the crack at the edge of track slab has the greatest impact on the stress of the door-shaped rebar under the positive temperature gradient, which is 157.9 MPa. The research results provide a theoretical basis for disease control.