Research On The Mix Proportion Design And Mechanism Of Fiber-reinforced Asphalt Chip Used As Stress Absorbing Layer

The condition of interlayer disposal in asphalt pavement is directly related to the overall performance of the pavement, especially of the semi-rigid pavement. Good interlayer disposal not only can effectively prevent or reduce pavement disease, but also enhance the integral bearing capacity of the road. Some research have been taken out to study with interlayer disposal of asphalt pavement, and made a number of effective measures for interlayer disposal. But the ideal state of interlayer disposal cannot be reached yet. So this research imported a new chip seal, the Fiber-reinforced Asphalt Chip Seal (FACS), used it as stress absorbing layer in asphalt pavement. Made a deep study of its mix proportion design and perform mechanism to provide a technical support for its extension and application.To study with the FACS, we should consider with the climate, the transportation and construction technology and so on of different places, and then make a pertinent design. On the base of an investigation of the interlayer disease of asphalt pavement and considering with the climate and transportation situation in Shandong province, the research analyzed the effect of contact state between pavement base and surface layer to stress distribution in pavement with finite element software, and studied with the mix design of FACS used as stress absorbing layer according with availability of raw materials in Shandong, designed new experiment methods for mix design of FACS and invented special equipments for these mix design tests. Through a lot of experiments, we tested the effect law of materials composition to pavement performance of FACS, and then proposed a mix design method which is suitable in Shandong province and established a road performance evaluation index system for FACS used as stress absorbing layer.The research made a deeply analysis of the mechanism of the FACS connected with the principle of composite structure in microscopic level for the first time. Using the knowledge of short fiber reinforced composite, the research revealed the bonding mechanism of the interface between fiber and asphalt, and used the concept of "probability of intensity of critical section" for the first time, to study the mechanical properties of FAS in "critical section", and then established a prediction model of "probability of intensity of critical section". Based on the model, it analyzed the cracking resistance of FAS and proposed the formula to predict the cracking resistance of FACS used as stress absorbing layer.With the experience from test road engineering, the research has also summarized a index system composed of shearing test, water seepage test and smoothness test, provides reference for the construction of the FACS used as stress absorbing layer in Shandong province and even in the whole country.