Research Of Theory On Application Of Geogrid In Asphalt Concrete Pavement

Along with the fast-growing national economy development, communications and transportation enterprises especially high grade highway construction, is in an extraordinary rapid growth period and overall pavement quality has improved remarkably. In order to minimize disease extent of asphalt concrete pavements, various treatment methods such as reasonable design and construction quality control are adopted home and abroad. However, along with the extremely serious asphalt concrete diseases as usual and actually distinctive heavy haulage and overloading phenomena in expressway, shear stress in cover, and tensile stress in the bottom of base and subbase as well as compression in top subgrade are increased with the acceleration of axis load which have obvious effects. Besides, pavement cracking is also a popular disease whose various methods prevention and treatment are adopted home and abroad. However it still seriously affects safety and comfortability of vehicle running. At the same time, as the increasing demand of roadway transportation along with the fast growing economic construction, all countries attach immense importance to studies on decreasing road diseases and improving its life. Asphalt pavement design overhaul period is 15 years but pavements in China always needs repair in 8-10 years. It is showed in data that the overall repair costs almost equals to new road construction costs subject to the assumption of 30 years road life which imply the great importance of improving highway life and postponing repair period.In recent years, various new materials, technique and technology are developed in high grade highway construction, especially the adoption of geosynthetic materials as reinforced material in pavements which has obvious technical advantages and sound economical effects. Seen from research findings, the contribution of geosynthetic materials towards pavement performance manifests itself in aspects of decreasing cover thickness and surface rutting ,preventing pavement cracking and extending road longevity. But it is necessary to realize that as a newly developed technology, duo to different material properties, performance and mechanism, its relating application and study are in a condition of abundant application but backward theories in which theoretical study is obviously backward. Although it is approved by test study and case application that geosynthetic materials contributes to pavement performance improvement to some extent, there still has no agreement on how to explain the way it works.In the view of reinforced pavement structure, this paper presents a comprehensive study and analysis on effects of geogrids to asphalt mixtures and pavement structure performance. Creating pavement structure model by FEM method, simulating the connection of geogrids and structure layers up and down with spring element, the connection condition of geogrids and structure layers are effectively simulated through different spring stiffness coefficient choice. Respectively creating FEM models of different geogrids application in entire pavement, in pavement which has full cracking in its base and in reinforcement of old pavement and mechanically calculating by ADINA program, this paper compares the difference of internal force and deformation before and after reinforcement and analyzes reinforcement materials contribution to cracking resistance performance of pavement structures and has acquire some useful theoretical results as well.