Research On Rutting And Fatigue Prediction Of Flexible Base Pavement

Asphalt pavement with semi-rigid base is widely used in China.However,due to its inherent reflective cracks,huge maintenance costs and relatively short service life,semi-rigid base asphalt pavement has higher life-cycle cost and gradually runs counter to the concept of green sustainable development.On the other hand,while the flexible pavement has the advantages of less aggregate consumption,lower maintenance cost and generally longer service life,but the domestic design theory and engineering experience of flexible structure are both insufficient.Therefore,it is of great significance to study the mechanical characteristics of the structure of flexible base asphalt pavement,especially the law of its fatigue and rutting evolution.Firstly,the paper summarizes and compares the current research results on the constitutive model of asphalt mixtures at home and abroad.Based on the researches of the viscoelasticviscoplastic-damage constitutive model of asphalt mixtures,the paper studies the changes of material mechanical properties during the evolution of fatigue and permanent deformation of asphalt mixtures.Secondly,the paper improves and simplifies the viscoelastic-viscoplastic-damage constitutive model of asphalt mixture in previous studies,and calibrates the parameters of the constitutive model of asphalt mixture by simple and feasible laboratory experiments.In addition,the complex constitutive model of asphalt mixture is compiled into the user material subroutine UMAT of ABAQUS to realize its numerical application.Afterwards,the paper systematically studies factors,the temperature and traffic load,which have significant influence on the evolution of fatigue and permanent deformation of asphalt pavement,analysing the characteristics of temperature field of asphalt pavement in different seasons and the distribution characteristics of vehicle load in time and space.Finally,the factors of traffic load,temperature field of pavement and mechanical constitutive model of asphalt mixture are coupling analysised by finite element software.Then,the paper studies the fatigue evolution law according to the damage evolution of asphalt layer bottom,and the permanent deformation evolution law according to the plastic evolution and plastic deformation distribution of asphalt layer.