Study Of Asphalt Pavement Structure Based On Adaptability Of Semi-rigid Base

At present the early damages in semi-rigid asphalt pavement make it a concerned problem that if semi-rigid base can continue to be used in China. It is a pressing problem how to enhance the adaptability of semi-rigid base from the aspect of pavement structure and improve its structural fatigue life, and then on base of them the design index and parameter are optimized. In order to research the target, the load, vehicle speed, environment and pavement structure should be comprehensively considered, and damage mechanism of semi-rigid base in different conditions should also be deeply analysed, which are both according to inadaptability of semi-rigid base and service life of asphalt pavement.Based on the spot investigation of semi-rigid asphalt pavement and existing documents, the main damage mode of pavement is analysed and then damage mode needed to be controlled is proposed which is on the basic of adaptability analysis of semi-rigid base. On the base of factors analysis effecting on cracking, the forces of pavement structure are analysed through numerical simulation in different load, temperature, coupling effect and vehicle speed with finite element software, which is also analysed in different contact states and base positions. Combined with different base structure and construction technology of semi-rigid base, reasonable using mode of semi-rigid base in pavement structure are advanced from the view of cracksing resistance. On the base of factors analysis effecting on cracking, the shear stress is analysed through numerical simulation in different load, temperature, coupling effect and vehicle speed with finite element software, which is also analysed in different contact states and base positions. Then the reasonable using mode of semi-rigid base in pavement structure is advanced from the view of rutting resistance. Using the model in finite element software, the crack tip stress intensity factor is calculated under independent load action and coupling effect, and then the structural fatigue life of semi-rigid base is fitted using formula of Paris. Combined with the change of structural fatigue life under different temperature and base module, the crack propagation law is proposed and the base module area and surface thickness are advanced which can extend the base fatigue life.Then the design methods of foreign and domestic is summarized and contrasted and deficiency in the design method is pointed out. The reasonable using system and design index and control model are proposed which is on base of semi-rigid base adaptability and stressing influence is comprehensively considered under different load, temperature and speed and contact state. Then on this basis the structure establishment of pavement structure is proposed which is based on the adaptability of semi-rigid base.