Mechanism Research Of The Fiber And Asphalt In Fiber Asphalt Stress Absorbing Layer

Rigid-flexible composite pavement is a form of long-life pavement structure, Thispavement structure can both reduces the usage of asphalt and make up for the deficiencyof driving comfort of the rigid pavement. This pavement structure is flexibility, and itimprove the performance of road. But the rigid-type base of this kind of pavementstructure have the construction joint and The defects of original crack. Under the impactof the Complex traffic composition and the bad environmental factors, Compositepavement will appear a lot of early disease that Reflection cracking is one of thecommon diseases. The technology of fiber asphalt stress absorbing layer can reduce anddelay the reflection crack of the Rigid-flexible composite pavement effectively.however，introducing of the technology in country introducing is a little delayed, andthe related performance and mechanism research of this technology is also few.First,The research Based on the theory of surface energy. Measuring the contactAngle Of the fibers, asphalt and cement concrete section Through the contact Anglemeasurement experiment. calculating the adhesion work to optimize seeking andevaluate the Adhesion performance of the material. Secondly, creating the finite elementcontact model of single fiber to simulate the case of single fiber in the matrix.Analyzing the Character of external force of the fiber-mechanical interface. Finally,creating Fabric finite element model to the Character of external force of The wholefabric model. the main conclusion of the research is as follows:①The adhesion work between fiber no.4and asphalt is maximum, followed by thefiber no.2, no.1and no.3. The adhesion work between Rubber asphalt and fiber ismaximum, followed by the SBS modified asphalt and emulsified asphalt. So, using fiberno.4and rubber asphalt in the fiber asphalt stress absorbing layer is more conducive toenhance the structure stability and improve the anti-cracking effect.②The adhesion work between Rubber asphalt and cement concrete section ismaximum, followed by the SBS modified asphalt and emulsified asphalt. So, usingrubber asphalt can Strengthen the cohesive force between the fiber asphalt stressabsorbing layer and the concrete slabs.③Simulation on the tension model of single fiber show that the trend of shearstress of the fiber-asphalt interface which calculated by ANSYS is similar to the trend of elastic-plastic model.④When the tension of Fiber Asphalt Stress Absorbing Layer achieve ultimatefailure state the fiber which is too short will be easy to pull out from the matrix. Thehigh strength properties of the fiber will not be given full play. In order to make full useof the strength of the fiber, the fiber should be longer than a critical value; But, if Fiberis too long, the growth of the share and diffusion of matrix stress the will not beobvious, which will cause the waste. So, we should choose a reasonable length of fiberin the design of the Fiber Asphalt Stress Absorbing Layer.⑤Enhancement effect of the fiber are closely related to the interface adhesiveproperty between fiber and asphalt: if the adhesive property of the fiber is too weak, thefiber enhancement effect will not be able to be given full play, which is resulting inwaste of material and economic; Good adhesive property is not only good for thetransferring stress, but also good for delaying interfacial debonding. So, in order toenhance material adhesion performance of the interface, we can choose composition ofthe Fiber Asphalt Stress Absorbing Layer reasonably. It can also improve themechanical properties of the Fiber Asphalt Stress Absorbing Layer effectively.⑥The addition of fibers can limit and constraint the strain of asphalt matrix; stressconcentration of The end of fiber might make the debonding between fiber ends andasphalt matrix, so the contribution to the end fiber fiber is very small.⑦The addition of short in fiber which length is one-sixth of the long fiber canreduce the resultant shear stress of the interface of fiber fabric model. It can absorb anddisperse the stress of matrix further more, and enhance the the whole mechanicalbehavior of the model.⑧distribution of fiber in the Fiber Asphalt Stress Absorbing Layer istwo-dimensional and random. Utilization rate of the fiber on stress direction is finite,and the distribution and orientation of fiber has a great influence in the utilization ratioof fiber. the closer the orientation between fiber and the loading direction, the higherUtilization rate of the fiber is.