Research On The Viscoelastic Damage Constitutive Relation And Its Application For Asphalt Concrete

Asphalt concrete pavement is a kind of structure which is widely used in highway in recent years. As the increasing of transportation volume and heavy communications, the damage of pavement is getting more serious. The research on the constitutive model of asphalt mixture is so useful that we can master the deformation law of pavement, predict the permanent deformation, it is very important and significant to prevent and inhibit the pavement damage. Asphalt mixture is a typical viscoelastic material; its characteristic is with memory. Its mechanical properties is closed to temperature, magnitude of the load and time, it is great significant for us to study the essence of the asphalt concrete material.In this paper, based on researches results of domestic and abroad, try to apply fractional viscoelastic model to describe the constitutive relation of asphalt mixture. It overcomes the defects of classical simple model which can not describe the relaxation and creep authentically. The parameters that need to be determined are few and their meanings are clear. Combined with fracture mechanics, apply of Sidoroff model to describe the evolution of damage for asphalt mixture. Coupled damage obtains constitutive equation of viscoelastic asphalt mixture; Make use of finite element analysis software ABAQUS, A three-dimensional model of pavement structure is built considering the viscoelasticity of asphalt mixture to simulate the reality pavement. The stress and deflection relaxation responses of asphalt pavement under load are simulated under different initial deformations. Viscoelastic material for asphalt surface will make the pavement stress reduce. Relaxation is independent of material properties without other factors. Another model is a pavement structure with reflective cracks, under the symmetrical and partial load, the crack, obtain that:the main reason of pavement crack reflection to the asphalt surface layer is the partial load, Study on the viscoelastic effect on the stress intensity factors of the crack tip, stress intensity factor occurs relaxation in anticipation, range of temperature for road surface will affect the internal structure of materials, With the incensement of decline amplitude, the corresponding stress intensity factor increases gradually, Relaxation curve becomes smooth with time. The higher the temperature, appearance of the stress intensity factor relaxation is more obvious.