Study On Microstructure And Numerical Simulation Of Asphalt Mixture Under Freeze-thaw Cycle

As one of the most commonly used pavement materials,asphalt mixture has a huge annual consumption in new road construction and road maintenance.However,as a complex mixture,the mechanical properties of asphalt mixture are very complex,and there are many internal and external factors that affect its performance.But with the continuous development of new technologies that can be used in the research of asphalt concrete means and methods are constantly updated,including X-ray Computerized Tomography applications in the field of materials science can make scholars in intact state studies the internal structure of asphalt mixture,and computer image processing technology and finite element analysis method for asphalt mixture of virtual numerical experiments become important means in the research of asphalt mixture.In order to study the effect of compaction method and basalt fiber on frost resistance of ac-13 compacted asphalt mixture,and to verify the feasibility of virtual numerical test based on CT scanning technology,the following research contents were carried out in this paper:(1)Matrix asphalt mixture and basalt fiber modified asphalt mixture were prepared by Marshall compaction and Superpave rotary compaction respectively,and 20 freezing-thawing cycle tests were conducted on them.The effects of compaction method and basalt fiber on frost resistance were studied by uniaxial compression static load creep test.(2)Combined with CT scanning technique and computer image processing technology,the asphalt mixture in the process of freezing and thawing cycle for the CT scanning,its internal structure of image,and through the handling of the internal structure of image segmentation which belongs to the part of pore,freeze-thaw cycle,compaction method is studied and basalt fiber on the influence law of mixture inside the pore.(3)CT scan images of asphalt mixture were divided into three components: pore,mortar and coarse aggregate through image processing,and its visualization model was reconstructed,which was further converted into a three-dimensional finite element model.The viscoelastic parameters of the mortar component were obtained through the mortar test and converted into the Prony series identifiable by the finite element model.The numerical test of uniaxial compression static creep test was carried out after the finite element model was assigned,and the experimental results of numerical test and laboratory test were compared to verify the feasibility of the method.