Analysis of Static and Dynamic Flexural Failure Mode of Double-Layer Concrete Composite Beam

To deal with the interface damage of non-ballasted tracks, the coordinated working performance of double-layer concrete was studied. From the mesoscopic perspective, actual aggregate distribution was obtained using the image processing technology, and the 2D model of double-layer concrete was established to simulate and validate the four-point flexural test. The influences of the loading strain rate on the flexural failure mode, the flexural-tensile strength and the macroscopic relationship of stress and displacement were explored. Results show that the simulated stress-displacement curve and failure mode are similar with the tested ones, which means that using the mesoscopic model to simulate the progress of crack propagation is feasible. Under the high loading strain rates of 110-2 /s and 110-1 /s, large damage occurs at the interface of double-layer concrete. When the loading strain rates are 110-3/s, 110-2/s,and 110-1 /s, respectively, the maximum bearing stress are 1.50, 6.41,and 14.40 MPa, respectively. The single crack propagates along the weak interface and transfers to the complicated multi cracks. Moreover, the crack width increases greatly and the concrete damage expands to the whole tension area.