Asphalt And Aggregate Adhesion Characteristics Analysis Based On The Principle Of AFM And The Surface Energy

As for the asphalt pavement, the adhesion between asphalt and aggregate interface has an apparent influence on high-temperature rutting, low-temperature crack resistance, moisture damage and even the germination of fatigue cracks. Further more, it will affect the quality, durability, safety as well as comfort. With the development and application of the surface energy theory, it seems that this theory has an obvious effectiveness and feasibility on the study of the adhesive property, moisture damage, etc. AFM has a conspicuous advantage in analyzing the the material microscopic physical and mechanical properties along with its technology becoming mature. Therefore, in order to study the adhesion properties of asphalt and aggregate, choose the theory of surface energy as the basic analysis principle and AFM as a major means of study based on combining micro and macro. Expect to provide a certain technical guidance on material design of asphalt mixture and durability evaluation.first of all, puts forward the corresponding way of sample preparation and test method according to the characteristic of AFM testing technology and the material characteristics of asphalt and aggregate samples, and then verify the validity of the test method through the analysis on the stability of the test results.Secondly, having expeiment on surface microstructure with different asphalt and aggregate. On the basis of the result from apparent appearance test on asphalt and aggregate, evaluate the surface characteristics of the microscopic structure of asphalt and aggregate qualitatively. Then, distinguish asphalt surface feature structure through MATLAB combined with SPSS statistical analysis and three-dimensional topography to seek the variation of the asphalt microstructure due to aging. Quantitatively Study the influntial factors and the cause of formation in connection with the asphalt’s four components changing results from aging.Thirdly, measure the force curves of aggregate and asphalt surface in particular mode, combined with the selected model and associated surface energy calculation theory, so as to obtain the surface energy of aggregate and the different region of asphalt, and then analyze the applicability and feasibility of different models. The result can be compared with the calculation results from conventional sessile drop method, analyzing the origin of difference between the old and new methods. According to the micro structural information of asphalt and chemical components, study the correlation between it and the asphalt surface energy, then the influntial factors can be determined as well.Finally, carriy out pull-off tests on different asphalt with different aggregate, thereby assess adhesion properties of asphalt and aggregate. According to the results from the pull-off test, comprehensively study the correlation between surface energy parameters, surface microstructure information and material adhesion characteristics, in that case we can explore the formation mechanism of adhesion at the micro level and the way to improve adhesion properties. Given all the results from research, generally develop a set of indecators to predict and evaluate the adhesive properties between asphalt and aggregate.