Study On Interface Action Characteristics Of Fiber Asphalt Mastic-aggregate And Mixture Performance

Fiber asphalt mixture can effectively reduce pavement diseases and extend the service life of roads.The addition of fibers changes the properties of asphalt mastic,thereby affecting the interface action characteristics of fiber asphalt mastic-aggregate,ultimately affecting the performance of the mixture.Therefore,in-depth research on the interface action characteristics of fiber asphalt mastic-aggregate is the key to analyzing the laws of fiber reinforced asphalt mixture performance improvement.This paper studies the effects of fiber content,fiber type,aggregate type,ambient temperature,and water environment on interface action characteristics and mixture performance,and explores the relationship between the two.First of all,three kinds of fibers(basalt fiber,glass fiber,polyester fiber),five kinds of fiber content(0.1%,0.2%,0.3%,0.4%,0.5%of the mass of asphalt mixture)and two kinds of aggregates(limestone coarse aggregate,basalt coarse aggregate)were selected to complete the ratio design of different types of fiber asphalt mastic and fiber asphalt mixture.Secondly,in order to explore the interface action characteristics and failure modes of the fiber asphalt mastic-aggregate,interface pull-out test(BBS)was used to test the interface action strength,and image processing was performed on the damaged interface to analyze and summarize the failure modes of different interfaces.The results show that with the increase of fiber content,the interface action strength presents a trend of first increasing and then decreasing.Basalt fiber has the best reinforcement effect on the interface action strength,and the interface action strength at low temperature is significantly greater than that at normal temperature,and the corresponding interface action strength of limestone aggregate is better.Under normal temperature,the interface failure mode is a comprehensive failure mode,while at low temperature,it is a single cohesive failure mode.Then,the crack resistance of fiber reinforced asphalt mixture was studied through the disk tensile test(DCT)of the mixture,and the correlation between crack resistance and interface action characteristics was explored using linear fitting and gray correlation analysis.The results show that basalt fiber has the best comprehensive improvement effect on the crack resistance of asphalt mixture.With the increase of fiber content,the overall crack resistance of asphalt mixture presents a trend of first increasing and then decreasing,and limestone coarse aggregate asphalt mixture has better crack resistance than basalt coarse aggregate.The linear correlation between interface action strength and fracture energy,as well as the opening displacement at peak load(P-CMOD),is good.Among multiple influencing factors,interface action strength has the greatest impact on fracture energy and P-CMOD.Finally,the fiber asphalt mastic and fiber asphalt mixture were subjected to immersion treatment,and the influence of water environment on interface action characteristics and crack resistance of the mixture was explored through immersion interface pull-out test and immersion disc tensile test.The results show that the interface action strength of fiber asphalt mastic-aggregate under water environment significantly decreases,and the peak load and PCMOD of fiber asphalt mixture decrease.The fracture energy decreases significantly,and the interface action strength is still the main factor affecting the fracture energy and P-CMOD.This study contributes to a deeper understanding of the interface action characteristics between fiber asphalt mastic and aggregate,and provides support for the in-depth study of the microscopic mechanism of fiber asphalt mixtures.