| Epoxy asphalt concrete is extensively used in steel deck pavement of long-span steel highway bridges.Due to the heavy traffic and the orthotropic structures of steel deck,the deformation ability,material strength and fatigue performance of epoxy asphalt mixture are required higher.The phenomenon of early fatigue cracks of epoxy asphalt concrete for steel bridge deck pavement still exists,thus toughening epoxy asphalt concrete is still a problem need to be solved in the future.In order to improve the scientificity and pertinence of epoxy asphalt concrete design,it is necessary to study and analyze epoxy asphalt mixture from the perspective of strength mechanics and microstructure.From the angle of composite material,in order to improve the fatigue resistance of pavement materials,the strength and toughness of epoxy asphalt mixture can be improved by addition of filler,such as fiber and powder material.The pertinence of epoxy asphalt concrete design can be improved by the microscopic analysis on active mechanism and optimized selection of filler.The performance improvement and mechanism of the addition of fiber and micrometer-sized particle filler into epoxy asphalt mortar and mixture are evaluated from the angle of mechanical properties and microscopic analyses and hoped to provide reference for toughened high-performance epoxy asphalt mixture design.Glass fiber is chosen to be the modifier for epoxy asphalt concrete by the analysis of fibers reinforced epoxy resin composite firstly.The tensile property of glass fiber reinforced epoxy asphalt mortar is evaluated by tensile tests.The result indicate that the strengthening effect is related to fiber length and dosage.The optimum dosage of glass fiber is decided by glass fiber reinforced epoxy asphalt mixture Marshall test,which is 5% of the epoxy asphalt mass.The result of flexural test and fatigue test indicate that the addition of glass fiber will remarkably improve the flexibility of epoxy asphalt mixture and the addition of 9mm glass fiber has the best result.The fracture surface of epoxy asphalt mortar and mixture is observed by scanning electron microscope(SEM),the result indicate that the dispersion of glass fiber affect its strengthening effect remarkably.Glass fiber with fiber length of 9mm’s strengthening effect is most remarkable due to its good dispersion and interaction length.The stair FA,the secondary FA,limestone and diatomite are chosen as the modifier for epoxy asphalt concrete and analyzed by Particle Size Analyzer,BET surface area measurement,scanning electron microscope(SEM)and X ray diffraction(XRD)analysis.The results of tensile tests and DSR are analyzed to reveal the performance improvement and mechanism of micrometer-sized particle filler based on the experiment results of filler’s characteristics analysis.The result indicate that the specific surface area is the major factor influencing on the performance of epoxy asphalt mortar.The fracture surface of epoxy asphalt mortar is observed by SEM and the result indicate that filler particle with high specific surface area can adhere well to epoxy asphalt,which should improve its strength properties.The limestone filler of epoxy asphalt mixture is replaced by stair FA and secondary FA to prepare epoxy asphalt mixture.The results of flexural test and fatigue test indicate that the addition of FA can improve the flexibility of epoxy asphalt mixture remarkably and stair FA has better effect.The addition of glass fiber and micrometer-sized particle filler can improve the flexibility of epoxy asphalt mixture remarkably.Glass fiber with fiber length of 9mm and dosage of 5% of the epoxy asphalt mass is the best effect.The flexibility of epoxy asphalt mixture can be improved remarkably by replacing mixture’s filler with FA,and the stair FA has better effect.The achievement of the experimental study of the article may provide a reference for the design of improving the strength and fatigue resistance of epoxy asphalt mixture. |
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