The Research For Influencing Mechanism Of Interface Bonding Property Between Asphalt And Aggregate

At present, the early damage of asphalt pavement, such as loose, peeling, pit slot damage phenomenon emerge in endlessly, greatly reduces the driving comfort and service life of the pavement. It is well known that these distresses are closely related to the bonding and adhesion between asphalt and aggregate, and often start from the interface which is the most vulnerable part. The nature of the interface phase undoubtedly becomes the key to the overall performance of asphalt mixture. Therefore, for solving the early disruption of asphalt pavement, it is necessary to study on the behavior and damage rules of the interphase under different external action. In this paper, based on the existing research achievements about the interface behavior of asphalt mixture, interface bonding behavior and failure mechanism of a single unit between asphalt and aggregate were studied. The main contents are as follows:First of all, a comprehensive overview about the current studies of asphalt and aggregate interface has been presented, introducing the existing mechanism of adhesion between asphalt and aggregate, evaluation methods and relevant test methods, influence factors as well as its mechanism of action, etc. Moreover, the viscoelastic properties and mechanical properties of the asphalt mixture were also described in detail. Based on the research results of predecessors, the article determined the bonding system and experimental methods, then formed two kinds of different specimens with the homemade loading device to prepare for subsequent experimental study.Secondly, using the shear test with self-designed shear clamp could get the whole force-deformationt curves of the two types of asphalt-aggregate specimens under different loading rates and different temperatures.One group of the samples was observed dual wave phenomenon at 25?,and more obvious with the increase of loading rate. The variation rules of shear strength with loading rate and temperature was analyzed. The result showed that aggregate surface topography had significant effects against shear strength;the shear strength increased with the increase of loading rate at a certain temperature while the shear strength decreased along with the rise of temperature at a constant loading rate; The impact factors of loading rate and temperature were reasonable and reliable in the quantitative description of interface performance sensitivity of asphalt-aggregate specimens, therefore, these two metrics provided a new means to evaluate the loading rate and temperature sensitivity of asphalt mixture that considering both aggregate and asphalt properties rather than the asphalt properties Only.Finally, the article analyzed the shear failure mechanism from the angle of energy change between asphalt and aggregate interface, and put forward the concept of shear energy so as to analysis the variation of energy along with the change of temperature and loading rate. Same law between shear energy and shear strength was achieved for the same specimens while abnormal appeared for two kinds of specimens at the temperature below 40?. Thus, only with the shear strength to characterize the ability of asphalt mixture to resist damage had some limitations, shear energy provided a new index, which is simple and easy to obtain.