Study On Composite Specimens Mechanical Properties In CRTS Ⅱ Slab Track

During the service of CRTS Ⅱ slab track,there is a debonding between track and CA mortar,which makes a difference to the stability of the tract structure and the service life of the train directly.The debongding is a typical damage in CRTS Ⅱ slab track,and the researches of the debongding are focus on illuminating the reasons of this damage,gaining the mechanical parameters of the interlaminar area,or analyzing the influence for the track structure.This paper takes the CRTS Ⅱ slab track for example with concret-CA mortar composite specimens doing experiments and theoretical research.The main conclusions are as follows:(1)Basing on lots of the theories and experiments of the bonding between new and old concrete,a tri-zones adherence micromodel of concrete and CA mortar is established to reveal the fragility of this special area.(2)The split tensile test is adopted to acquire the concrete-CA mortar composite specimen tensile property.On the macro level,the specimen is separated from the middle bonding area.The loading area is under high compressive stress,While the middle under tensile stress.And the crack grows at the middle,expanding along the bonding area to the end.The average split tensile strength of flat specimen and rough specimen are 1.333 MPa and 1.815 MPa,tensile elastic modulus of bonding area are 268.3 MPa and 396.9 MPa.(3)The shear failure of concrete-CA mortar composite specimen is brittle,taking place in the bonding area.Cracks grow at one loading head,expanding along the weak area towards to the another one.The average shear strength of flat specimen and rough specimens are 1.973 MPa and 2.4 MPa,shear elastic modulus are 1.333 GPa and 1.662 GPa.(4)Considering the geometrical characteristic of the bonding interface,fractal can be used to simulate the interface of the concrete and the CA mortar with dimension D = 1.262.And cohesion model can be employed in simulating the experiments with fractal model.The results of the simulating and the experiments are similar to each other,verifying the accuracy of the fractal interface model and the finite model.