The Bonding Characteristic Research Of Aggregate-Asphalt Mortar Interface

Asphalt mixture is consist of asphalt mortor, aggregate and the porosity of the random distribution, aggregate-asphalt mortar interface as a weak link, it is necessary to study the interface bonding properties. The adhesion of asphalt and coarse aggregate is charactered qualitatively in the existing specifications, it is influenced strongly by hunman factors. For the representation of quantitative methods, most tests the tensile or shear capacity of asphalt-aggregate interface, in actual driving load, the interface stress model is in a mix state, therefore how to represent interface bonding characteristics quantitatively and realistically become an urgent problem of road workers. Considering mechanical model, the paper research asphalt- aggregate interface bonding characteristic from two aspects: static and dynamic.Firstly, acquir ing basic properties of raw materials through indoor test, confir ming the performance of selected raw materials meets the specification requirements. Obtaining viscoelastic properties of different asphalt mortar in different contact conditions based on frequency scanning, according to the characteristic of viscoelastic material internal theory, analyze the best cement tatio of asphalt motar power under different contact condit ion. Designing a test device, which can measure the aggregate-asphalt mortar interface fracture strength in tensile-shear mixed mode. Acquir ing maximum stress value of different aggregate asphalt mortar combination under different strctching angle based on the drawing test.Secondly, considering the main factors of interface, simplify the interface, then get the aggregate-asphalt mortar interface mechanical model. Establishing drawing test finite element model through ABAQUS, specify cracks in the model in advance, comparing the numerical simula tion results and experimental results, in order to verify the rationality of the model. Based on strain energy density changes of interfacial mechanics crack tips, get aggregate- asphalt mortar interface fracture criterion, combining with the interface stress-strain response of the finite element model, obataining interface fracture criterion parameters under different aggregateasphalt mortar combination, analyze interface bonding characteristic in static condition.Finally, based on the rheological properties of the viscoelastic material, through the strain scanning test to determine asphalt mortar linear viscoelastic range, the viscoelastic fatigue test load values must be within the scope of linear viscoelastic range. Combing with the viscoelastic parameters change rule of asphalt mortar fatigue test under different contact condit ion, put forward aggregate-asphalt mortar interface fatigue evaluation index, analyze interface bonding characteristic in dynamic condition. Observing the nano structure of aggregate-asphalt mortar by means of AFM, then reveal the interface behavior by the three-dimensional topography.The study obtain fracture criterion under static condition of aggregate-asphalt mortar in mixed mode, it can be used as numerical simulation of the interface failure criteria in the future, this criterion is more close to the stress of the pavement. The interface bonding characteristic under dynamic condition can be obatained intuitively by interface fatigue evaluation index.