Investigation Of The Interface Structure And Adhesion Mechanism Between Asphalt And Aggregate

With the rapid development of highway, quality alkaline has been excessively andblindly used, while large amounts of local acid and neutral aggregates leave unused. This isbecause the adhesion between acid and neutral aggregates and asphalt was considered poor. Inorder to improving the interface strenth of asphalt-aggregate, enhancing the quality of asphaltpavement and making full use of the acid and neutral aggregates. There are theoretical andpractical significance to evaluate the adhesion mechanism between asphalt and aggregate.Based on interface theory, aggregate angularity coefficient measurement test, scanningelectron microscopy (SEM) and matlab of fractal dimension calculation method were used toresearch and characterize surface morphology characteristics of aggregates in both macro andmicro points. X-ray diffraction(XRD) was used to analyze the main chemical components.Scanning Electron Microscopy(SEM) was used to compare asphalt-aggregate interface,Pull-off test was used to measure the interface strength..Dynamic Shear Rheologicaltest(DSR), X-ray Photoelectron Spectroscopy(XPS) were used to analyze the main chemicalcomponents and chemistry reaction in limestone and granite-asphalt interface. At last, therelationship between performance indicators and strength of asphalt-aggregate interface wasstudied.The result of the research showed a positive good correlation between the angularcoefficient of aggregate particles and their surface texture fractal dimension, as well asaggregate particle surface fractal dimension and strength of asphalt-aggregate interface. Therougher of the surface degree was, the higher interface strength were. The results of XPS testshows chemical reaction existed between the CaCO3in the limestone and the S element in thesulfoxide functional groups of asphalt with a small participation amount, which enhanced theasphalt-aggregate interface. Asphalt mixture tests shows the strengths of the asphalt-aggregateinterface directly affect the performance of mixture. The effective way to enhance the strengthof the asphalt-aggregate interface is improving the surface texture of aggregate particles.