Study On Microstructure Of Asphalt Binder Of Hot Mix Plant Recycling

The plant mixing heat regeneration technology is currently the most controllable quality of the mixture,and can realize the regeneration technology of RAP to the greatest extent,and the application prospect is considerable.However,the understanding of the microstructure of asphalt binder is insufficient,and it is impossible to reasonably use the regeneration mechanism to guide the regeneration of aged asphalt.It is one of the main reasons for the low regeneration efficiency of recycled asphalt mixture.Based on this,this paper uses a series of microscopic testing methods to conduct a comprehensive study on the microstructure of reclaimed asphalt,assisting in the macroscopic test method,establishing the relationship between microstructural characteristics and macroscopic performance,and evaluating the regeneration effect of reclaimed asphalt for multi-scale evaluation.basis.Firstly,two batches of aged asphalt were obtained by an improved extraction evaporation method and an indoor aging test.For the aged asphalt recovered from the pavement,two sets of recycled asphalt were obtained by the method of blending SBS new asphalt + regenerant and adding only new asphalt,and the indoor asphalting test of new asphalt and recycled asphalt was carried out to obtain four groups of recycled asphalt with different degrees of aging.For the old aged asphalt with three degrees of aging indoors,another batch of recycled asphalt is obtained by adding the raw asphalt.Secondly,microscopic experiments such as atomic force fiberscope(AFM),gel permeation chromatography(GPC)and Fourier transform infrared spectroscopy(FTIR)were used to test the microstructure of the aged asphalt as RAP recycled asphalt,and analyzed the time.The influence of RAP content,regenerant and aging degree on the microstructure,quantify the change of microstructure,and summarize the change law.Then,the macroscopic performance test method was used to test the regeneration effect of RAP content of recycled asphalt,and compared with SBS new asphalt,the effects of regenerant and RAP content on the road performance of recycled asphalt were summarized.And try to establish a connection with the microstructural characteristics to explain the reasons for the changes in macroscopic performance from a microscopic perspective.Finally,atomic force microscopy experiments were carried out on another batch of recycled asphalt to compare the difference between the aging and regeneration mechanism of matrix asphalt and SBS modified asphalt.The existing experimental results were tested and supplemented.Studies have shown that the modifier in SBS modified asphalt can not only enhance the high and low temperature performance of the pavement,but also improve the anti-aging performance of asphalt,and also affect the microstructure of asphalt surface,so that the microstructure of SBS modified asphalt with aging and regeneration The degree of change is different from the matrix asphalt.