Viscoelastic Properties Of Asphalt Mixture And Its Effect On Pavement Response

Along with the fast development of the transportation industry and depth researches about the pavement materials and pavement structure, it has already become a trend to make more studies about viscoelastic behavior of asphalt and asphalt mixture and pavement performance. The analysis of mechanical responses about pavement structure is the kernel to explain the mechanism of the pavement diseases and then the design of pavement structure. Moreover, the mechanics parameters and constitutive relation of pavement materials is the basis for the analysis of mechanical responses. This paper, on one hand study asphalt mixture and its viscoelastic parameter model and put forward two model theories. On the other hand, through the contrast between the mechanical responses under the simulation of a road loaded of moving vehicles and also taking advantage of ABAQUS which is a finite elements to carry on the modeling and the mechanical responses obtained under the current elastic theory, the viscoelasticity theory will be frequently put into use in pavement designing.Firstly, by conducting the triaxial complex modulus experiment under three different operating conditions, it can obtain the storage modulus, loss modulus, dynamic modulus and phase angle of the asphalt mixture under different experimental conditions. By building the principal curve of the isobaric storage modulus and analyzing the influence of confining pressure on viscoelastic mechanical response of asphalt mixture, the new principle curve of the isobaric storage modulus under the reference temperature and reference confining pressure will be built and the viscoelastic mechanism model considering the confining pressure will also be established.Secondly, the modified HN model which is more suitable for the viscoelasticity characteristic of asphalt mixture will be formed after making improvements in the original HN model and furthermore expressions of storage modulus and loss modulus will be obtained. Fitting experimental date related with the storage and loss modulus in the triaxial complex modulus experiment and induced formulas through mathematic method determines the material parameters and parameters related with temperature of the modified HN model and further build an unified model--HN model which has unified material parameters.Lastly, based on the ABAQUS which is a finite elements sofeware, it is easy to build the finite element pavement model and to make a finite element simulation. Taking the pavement materials into viscoelasticity and elastic materials respectively and loading the half-sine wave load on the road to make a finite element analysis and calculate the control index present pavement structure rules which are surface deflection and flexure stress of bottom of asphalt layer and semi-base layer. This paper study the variation law of mechanical responses in different temperature and vehicle speed during analysing two kinds of mechanical responses obtained by contrast of two different materials parameters. Beyond that, the paper also explain the laws and reasons for this kind of phenonmenon to lay the foundation of improvement of asphalt concrete pavement design.This paper aims to provide a more complete idea for analysis of the asphalt mixture viscoelastic mechanical behavior and then, promote application of the viscoelastic theory in road design. At the same time, by further analyzing the impact of various design elements of pavement structures, propose the countermeasures of delaying disease emergence and development, in turn, can provide an effective way to optimize the design of the pavement structure.