Simulation and evaluation of fatigue damage of cold recycled mixtures with bitumen emulsion

•The numerical model of cold recycled mixtures with bitumen emulsion (CRME) was established and the simulation splitting test was carried out by Particle Flow Code in 2 Dimensions (PFC2D).•The reliability and accuracy of the discrete element model (DEM) were verified by the simulation of CRME and the indirect tensile fatigue test in the laboratory.•The fatigue damage evolution process of CRME and the damage characteristics under dynamic load were described. In order to explore the fatigue damage mechanism of CRME under dynamic load, DEM of CRME was established based on PFC2D. The micromechanical response characteristics of CRME were obtained by simulation splitting test, and verified by indoor indirect tensile fatigue test. It shows that the results of simulation test are basically consistent with those of indoor test. The numerical value and quantity of tensile force chain in DEM increase obviously with the increase of the stress ratio, the fatigue life decays rapidly, and the horizontal displacement at different width positions in the specimen increases significantly. The tensile force chain is generated, accumulated and concentrated in the mortar and the aggregate-mortar interface. Eventually, the micro structure and bonding force of CRME are damaged. Tensile force chain is the main factor of fatigue damage. The improvement of the bonding performance of bitumen emulsion cement mortar (BECM) and RAP-mortar interface is suggested to improve the fatigue performance of CRME.