Research On The Adhesion Characteristics Of Warm Mix Asphalt Based On Atomic Force Microscope Technique

Warm mix asphalt(WMA) is a green pavement construction material which is helpful to energy saving and helpful to minimizing the emission of greenhouse gas, reduces the resource consumption, and also avoids the asphalt to some extent pre-aging. But, the lower temperature mixing, construction technicalcharacteristics of the lateperformance has been a great challenge, especially the performance of warm mix asphalt pavement in service during the anti water damage ability is insufficient to make the application of warm mix asphalt mixture is restricted. The main causes of water damage of asphalt mixture is in service in the process of long-term aging, besides, the water leads to a decrease in adhesion between asphalt and aggregate, eventually lead to asphalt pavement damage. So the research of warm mix asphalt aging process on the adhesion properties of warm mix asphalt mixture is significant.Three kinds of commonly used matrix asphalt,two kinds of warm mix agent in Gansu province were chosen inthis paper. They were used to made warm mix asphalt, and Atomic force microscope, Gel permeation chromatography and Infrared spectroscopy were used to analyze the adhesive in the process of asphalt aging. Firstly, the microstructures of asphalt surface morphology observation, mixing add heating agent and aging process on the microstructure of asphalt were analysed by AFM. Second, the force spectrum nano adhesion strength was test by AFM, combining the macroscopic surface test, analyse the adhesion characteristics different ageing process of warm mix asphalt. Finally, The changes in concentrations of each molecule of warm mix asphalt aging were test by GPC, the change of functional groups in the process of warm mix asphalt aging were test by FTIR.combination the GPC and FTIR analysis warm mix asphalt aging mechanism.The results show that: firstly,heat mixing agent and different degrees of aging had certain degree of influence on asphalt topography, the height of Bee-structure were increased with Sasobit but decresed with Evotherm. The height of "Bee-structure" increased and the asphalt surface roughness increased significantly with the aging degree of improved. Phase diagram of each phase in the boundaries become blurred after aging, It is worth noting that KELIAN asphalt had a big change in topography is bigger, there aer some Bee-structure in its surface after aging. Secondly, nano adhesion strength test results and surface energy results were consistent and had a higher fitting degree, the ashension force of matrix asphalt were increased with Evotherm, but decresed with Sasobit. Besides, with the degree of aging aggravated the adhension of asphalt decresed too. Last, the infrared spectrum test results show that, the oscillation of KELIAN asphalt is higher than other two asphalt, and the S=O oscillation of asphalt increased with Sasobit, but increased with Evotherm. With the aging process, the C=O oscillation and S=O oscillation increased significantly. Besides, the LMS content of asphalt decresed and SMS contant increased with Evotherm, theSMS content of asphalt decresed and LMS contant increased with Sasobit. With the aging process, the LMS content were increased and SMS conten decresed in all asphalt.