Study On The Interfacial Mechanical Characteristics Of Modified Asphalt Mixture

With the constant improvement of public infrastructure, the road construction of our country has made great development in the new century, asphalt pavement has become the most important type of pavement for highway and municipal road construction at home and abroad because of its good road performance. At the same time, scholars both at home and abroad have devoted to the research of asphalt, asphalt mixture and asphalt pavement, and the research results also emerge in endlessly. Based on the digital image correlation technique, in this paper, it discussed two common asphalt pavement layer materials- the SBS modified asphalt mixture and the rubber powder modified asphalt mixture in the process of crack fracture and development characteristics and mechanical properties of the change of strain field from meso-scale using indoor test, and also analyzed the effect of temperature aging, ultraviolet light aging, water freezing and thawing cycle, salt solution freeze-thaw on the deformation and mechanical properties of the different specimens.Through the analysis of the data from VIC – 3D and the image from electron microscope, it is concluded that the asphalt mixture can be divided into asphalt mortar,interface area and coarse aggregate when it was studied, the interfacial zone is the weakest part of the specimen, and crack fracture and the development of macroscopic fracture is conducted along the interface zone; the development of the macro crack includes two processes- the beginning of the micro cracks and the connecting of micro cracks, aging is mainly affected the properties of the modified asphalt and freezing and thawing cycle mainly affects interface in nature, these two factors both shorten the time of the connecting of micro cracks.The fracture energy density(FE) and the fracture toughness(Jc) was used to evaluate the fracture performance asphalt mixture specimens, the results were basically the same with each other, so the correctness of these two parameters was proved; the FE and the Jc of rubber powder modified asphalt specimen were both greater than these of SBS modified asphalt specimen in this experiment under the different environment, this illustrated that the rubber powder modified asphalt mixture has better crack resistance at low temperature, and its mechanical properties was less affected by the environment;ultraviolet aging has the greatest impact effect on the mechanical properties of asphalt mixture specimen, the rest were the aging temperature, salt solution freeze-thaw cycle,water freezing and thawing cycle in order.In addition, modeling of indoor test specimen was formed based on the principle of cohesion model, and viscoelastic parameters was deduced using the empirical formula,and then using the finite element software of ABAQUS to simulate the failure process of the specimens. The results show that, simulation results and experimental results are basically the same, so using the finite element simulation can predict the result of the test.