Study On Fiber Sealing Performance And Finite Element Simulation Based On Stress Absorption Principle

The fiber seal layer is a stress absorbing layer laid between the semi-rigid base layer and the surface layer in recent years.It can absorb most of the concentrated stress from the reflective crack tip,thereby reducing the stress concentration phenomenon at the crack tip and preventing the crack from furthering.Extension,it has a significant effect on extending the life of the road.Based on this,this paper conducts relevant theoretical research and road performance test research to provide technical support for the popularization and application of this technology.Since the fiber seal layer is a viscoelastic composite material,this paper first analyzes the mechanism and energy consumption of the fiber-reinforced asphalt stress absorption layer according to the interface theory in composite mechanics and the energy consumption theory in viscoelastic mechanics.According to the analysis of interface theory,it is concluded that modifying the fiber can improve the interface bonding strength between it and emulsified asphalt,so that the fiber seal layer can play a better crack resistance effect,and at the same time,according to the energy consumption theory,the stress at the crack tip can be used to seal the fiber seal.The work done by the layer will be converted into elastic strain energy and dissipation energy of the fiber seal layer.The sum of the two constitutes the fracture energy of the fiber seal layer.The larger the value,the more crack tip stress can be absorbed,so the Fracture energy is used as an index to evaluate crack resistance.Then,based on the fatigue research results of domestic and foreign scholars on the asphalt mixture,it is speculated that there is a linear relationship between the cumulative dissipated energy and the number of fatigue times of the fiber seal under the fatigue load under logarithmic coordinates,and it is carried out by fatigue tensile test Verified.According to the results obtained from the theoretical analysis of the interface,the glass fiber was modified with a coupling agent,an acid and alkali solution with a concentration of 1 mol / L and 2 mol / L,respectively,and the microscopic morphology of the modified fiber was investigated using a scanning electron microscope.Observation,the results show that the surface roughness of the modified fiber increased significantly,and through the strip tensile test using the fracture energy as the evaluation index,the glass fiber modified with 2mol / L acid solution was the best.Subsequently,the effects of fiber type,temperature and load frequency on the complex modulus,phase angle,rutting factor,storage modulus and loss modulus of fiber-reinforced emulsified asphalt composites were studied through dynamic shear rheological tests.The results show that the modified fiber can increase the complex modulus and rutting factor of the composite material and reduce its phase angle at different temperatures and load frequency,compared with the unmodified original fiber,thereby improving the composite material.The ability to resist permanent deformation and enhance its crack resistance.In addition to the good crack resistance,the fiber seal layer also needs good interlayer bonding ability.By making a composite test piece indoors,the interlayer shear strength and interlayer pull strength are used as the interlayer bonding performance evaluation indicators.The effect of material composition on the interlayer bonding strength of the fiber seal layer was studied.Finally,through finite element simulation,the stress intensity factor of the crack tip at the bottom of the fiber seal layer under different conditions(axial load,surface layer thickness and semi-rigid base modulus)of the fiber seal layer is calculated to analyze the difference the impact of layer performance.