Research On The Viscoelasticity Constitutive Model And Damping Characteristics Of The Asphalt Mixture

The asphalt mixture has spread energetically because of the rapid development of expressway. The asphalt mixture has striking viscoelastic characteristics. In previous research, it was regarded as a kind of linear elastic material but it is really different with the actual situation. Based on the features of viscoelastic characteristics and the constitutive relation of the asphalt mixture, its some other properties can be discovered, such as the damping which has researched in this paper. The research can make researchers to use the better characteristics scientifically and reasonably so that the right material can be used in the right place.First of all, in order to research the asphalt mixture as damping material so the features and mechanical model of the damping materials were analyzed at first. Then, the constitutive models of the asphalt mixture were introduced briefly. Additionally, two ways of determining the damping value of the asphalt mixture were put forward:one of ways is suspensi on dynamic method and the other is dynamic creep test method with giving the corresponding calculation methods.Moreover, for the study of the influence factors on the asphalt mixture, the dynamic creep test method and the energy method (constitutive relation hysteresis curve) were be made use of to get the damping parameter which is represented as loss factor. The study found that damping of asphalt mixture are presented the rule of from increase to reduction with the increase of temperature or frequency. In the temperature range of 20～60℃, the value of loss factor is floating in the interval of (0.040,0.090) while the damping effect of asphalt mixture is better when the frequency is in the range of 1～10Hz. Also in this paper, the damping of CA mortar was determined to be compared with the asphalt mixture. It is found that the damping trend is similar with asphalt mixture when the frequency is 0.2-lHz and the loss factor has the range of (0.090,0.110), while in 5-25Hz, the damping effect weakens quickly and the loss factor value is close to 0.040. Then this paper made use of dynamic modulus test to verify the damping characteristics of the asphalt mixture. The results showed the consistency of the law under different influencing factors and the damping value can achieve the optimum effect at about 40℃.Finally, this paper gave the first step to research the damping performance of the asphalt pavement structure and proposed the research ideals and methods, as well as the technical support of the finite element software.