Research On Fatigue Damage And Creep Damage Properties Of Asphalt Mixture Under Repeated Loadings

Compared with other forms of pavement, asphalt pavement has more superior performance, so its applications in road engineering are also increasingly widely. However, with the development of asphalt pavement, there have been a series of problems, one of the most important form is fatigue damage. therefore, in order to better understand the fatigue properties of asphalt mixtures, it is necessary to study them in a variety of fatigue test, and in order to provide additional reference for parameters design and structural design of asphalt pavement.Fatigue damage and creep damage performances of asphalt mixture are analyzed in the paper through indoor asphalt mixture uniaxial tension and compression fatigue tests, direct tensile fatigue test and static creep test. Firstly, the uniaxial tension and compression fatigue equations are fitted based on arbitrary nominal and real stress ratio in order to predict the fatigue lives , which also compared to the direct tensile fatigue damage equation fitted under the same test conditions, and the change law of parameters k and n is get in two kinds of fatigue equation. Then, from the angle of damage mechanics, select the elastic modulus foe damage variables, a fatigue damage evolution equation is established at the same load frequency using the relevant fatigue damage model, by which the asphalt mixture tension and compression fatigue damage evolution laws is get, at the same time the creep damage characteristics are analyzed through creep damage under both high stress and low stress which calculated by classical plasticity fracture models and ductile fracture model. Then using haversine fatigue stress decomposition principle, in the same experimental conditions, tension and compression fatigue damage, creep fatigue damage and direct tensile fatigue damage are respectively calculated and analyzed at the corresponding test conditions, thus the exist of fatigue-creep interactive coupling is proposed, than the coupling mechanism are discussed. Soon afterwards, using the related model, the test data are fitting, fatigue-creep coupling interaction equations at both the same different load frequency while different stress level and the same real stress ratio while different load frequency are established, which compared with measured data, good agreement is get.Finally, on the basis of the above work, the shortcomings of this study are analyzed, which propose number of views for further work.