Properties Research On Non-continuous Fiber Reinforced Emulsified Asphalt Gravel Stress Absorbing Layer

In the highway construction in China, semi-rigid base and subbase with cement stabilized material or lime and fly ash stabilized material is the main form of pavement structure of highway. At present, the crack problem increasingly has become the main defect of this structure. Fiber reinforced emulsified asphalt stress absorbing layer have good performance of stress absorbing, good anti-cracking, good waterproof performance, high stability, fast construction, convenient for recycling, in foreign countries has been widely used as stress absorbing layer between base and surface. At present this technology only stay in introducing the construction process, lacking theoretical research and selection of material, material consumption is largely basic on experience value, the amount range of different researchers recommend is bigger, does not have mix design method, lacking of process control index of construction, etc. In this paper, carrys out theory and experimental study in-depth of this technology base on the Chongqing and Jiangsu Province Traffic Science and Technology Projects.This paper from the micromechanics angle of composite material, by measuring the contact angle, obtains the adhesion work of the different fiber and emulsified asphalt, uses the principle of work and energy to calculate and compare strain and losing energy between different fibers and emulsified asphalt, makes fiber optimization scheme. Analysis of different fibers selective absorbing characteristic functional groups of emulsified asphalt by infrared spectrum, provides methods for the fiber surface modification.Application of basic principles of fracture mechanics, using finite element numerical analysis of anti-cracking effect after laying fiber reinforced emulsified asphalt stress absorbing layer on three kinds of cracking model (reflection crack, Top-down crack, docking crack). In-depth study the stress absorbing layer modulus, thickness, the reflection crack width, interlayer contact conditions and thickness of asphalt mixture overlay influence on crack resistance effect.From the fracture energy point of view, analysis fracture energy of fiber reinforced emulsified asphalt stress absorption layer material at different levels, and factors affecting the fracture energy and the best amount of material combination, compare fracture energy of the different stress absorbing layers. A comprehensive analysis of the main factors and the best dosage combination, which impact the other mechanical index (maximum bending force, the deflection, shear force, interlayer adhesive force, cycle fatigue loading times). Discuss about the influence of stress absorbing layer thickness and overlay thickness on the reflective cracking resistance performance of composite pavement structure.Dynamic monitor cracking development in composite pavement structure after laying different stress absorbing layer, comparing cracking development of the different stress absorbing layers; establishment grey relational degree of crack development in different periods (early, mid, later) with all mechanical index, according to the correlation value, determine relevant parameters, which have the maximum correlation degree with cracking development velocity, and as a main design parameters for stress absorbing layer.According to the maximum work and energy principle obtain optimal fiber asphalt content ratio, base on gravel and semi-rigid base absorption rate of emulsified asphalt mixture, puts forward the semi-empirical design method. According to the law of crack development and mechanical index correlation analysis results, use the maximum bending force, shearing force and fracture energy as the main mechanical parameters, put forward the test design method. According to the research results, example the fiber stress absorbing layer design application and the main construction controlling points.