Fatigue damage numerical simulation of cement-treated base materials by discrete element method

Abstract

Fatigue failure of the cement-treated base (CTB) is always paid more attention by highway constructors. Meso-scale cracking evolution plays an essential role in the research of fatigue deterioration mechanism, which is hard to be characterized using experimental techniques alone. The objective of this paper is to investigate the fatigue behaviour of CTB materials under cyclic loading through the discrete element method (DEM). A parallel bond evolution model (PBEM) was developed to simulate the time-dependent fatigue damage. Integrated with the PBEM, a fatigue damage evolution model (FDEM) was established and implemented in the Particle Flow Code (PFC5.0) to describe the fatigue decay behaviour under cyclic loading. The fatigue modelling parameters were further calibrated by the notched semicircular bending (NSCB) strength and fatigue test. Then a series of virtual NSCB fatigue tests were conducted to study the decay law of CTB materials. The simulation results indicate that the fatigue damage accumulates in a nonlinear manner under cyclic loading and the steady crack growth is the main stage of fatigue failure. With the increase of stress ratio, the stable crack growth stage is shortened obviously. The established PBEM is capable of capturing the fatigue behaviour and cracking process of CTB materials. It provides a reliable numerical technique for modelling and investigating fatigue damage of cement-treated base materials.