Experimental Study On The Effect Of Fine Aggregate On The Performance Of Skeleton Asphalt Mixture

With the rapid development of highways in China,asphalt pavement has been widely used.The raw materials of asphalt pavement are asphalt,aggregate,filler and so on.Aggregate refers to the general term of granular materials such as gravel and gravel with different particle sizes,which can be divided into coarse aggregate and fine aggregate.Coarse aggregate acts as the skeleton structure of the mixture,and fine aggregate plays a filling role in the mixture,but the gradation,geometric characteristics and cleanliness of fine aggregate are important factors affecting the road performance of the mixture.This paper focuses on the influence of fine aggregate on the performance of skeleton asphalt mixture,mainly examines the influence of three technical indicators of fine aggregate gradation,angularity and sand equivalent on the performance of asphalt mixture.Using two different fine aggregates of stone chips and machine-made sand,three gradations with different thickness were selected within the range of the gradation curve specified in the specification to study the effect of gradation on the performance of asphalt mixture.The sand equivalent and angularity of two kinds of fine aggregates under three gradation mix design were measured.The same level of two different fine aggregates were mixed in different proportions to adjust the angularity of fine aggregates,and the sand equivalent value of fine aggregates was adjusted by adding soil.Orthogonal test was used to optimize the test combination.The dynamic modulus test,immersion Marshall test,freeze-thaw splitting test and trabecular bending test were used to evaluate the high temperature stability,water stability and low temperature stability of asphalt mixture.The test results show that the grading,angularity and sand equivalent of fine aggregate have significant effects on the pavement performance of asphalt mixture.Among them,the high temperature performance of asphalt mixture is affected to some extent,and the high temperature performance is the best when the grading is medium.Grade matching asphalt mixture has great influence on low temperature performance.Sand equivalent has great influence on water stability of asphalt mixture.