Study on damage behavior characteristics of asphalt binder under strain loading condition

Abstract

The fatigue behavior of asphalt mixture is the main reason that affects the service performance and service life of asphalt pavement. The fatigue mechanism of asphalt mixture is still unclear. In fact, the fatigue damage of asphalt mixture is mainly related to the nature of asphalt binder. Therefore, the study of the damage of asphalt binder is beneficial to reveal the fatigue failure mechanism of asphalt mixture. At present, there is no clear damage behavior method of asphalt binder. Considering that the damage behavior of asphalt binder is actually related to its rheological behavior, the shear rheological method is used to evaluate the damage behavior of asphalt binder. The complex modulus is used as the evaluation index of asphalt damage behavior. Because the strain loading mode is consistent with the actual force of the binder in the asphalt mixture. The damage behavior of asphalt binder is studied by time scanning mode under controlled-strain mode. The influence of temperature, loading frequency, and other parameters on the damage behavior of asphalt binder is analyzed. Through the data analysis, the asphalt damage curve meets Boltzmann distribution. At the same time, the characteristics of asphalt damage curve are analyzed. It is proposed that there are three inflection points and two platforms for the typical damage curve of asphalt binder. The three inflection points divide the damage behavior of asphalt into elastic deformation stage, yield stage, crack growth stage, and failure stage. The effects of temperature and loading frequency on the curve characteristics are summarized. For asphalt binder with higher stiffness, the damage curve of asphalt binder is “L” type when the strain level and loading frequency are larger. When the temperature is higher, the loading frequency is smaller, and the strain is smaller, the damage curve will gradually change to anti-“S” type or even linear.