| The application of binder stabilized mixture in semi-rigid has eliminated the diseases of asphalt pavement like frost boiling and deformation, also greatly improved the riding quality and service life. The advantages of semi-rigid base include:use local materials effectively, high strength and stability. But with the economy growing, road traffic and vehicle load increase rapidly, combined with some unreasonable design and construction, the damages of pavement increase badly, pavement quality decreases year by year. Many early roads close to their life time, damages occur on some new roads too. The surface damages of road cannot be ignored.Damages affect the safety and comfortableness of vehicle driving. The present study of pavement damages cost much time and energy on disposal method, but the study on damage causes and failure mechanism is still little. Semi-rigid base material has a certain applicability, in different environment and different loads, reasonably design of material composition and structure is very essential in improving the whole performance and prolong the service life.Based on the detailed field survey of damages on typical semi-rigid asphalt pavements, various damage phenomena of pavement were recognized systematically; using analysis softwares include BISAR, PADS and ANSYS, the mechanical calculation of semi-rigid base asphalt pavement was analysed; consider the mechanical properties in the case of semi-rigid base cracking; as the base cracks and modulus degrades, the degree of cracking and cracking coefficients were used to describe the mechanical properties of pavement structure; combined with the analysis of mechanical properties, the cold, heat and wet conditions were studied and the corresponding semi-rigid asphalt pavement structure optimal case were proposed.The conclusions as follows:(1) The common distresses in semi-rigid base asphalt pavement are longitudinal cracks, transverse cracks, chap, network cracks, rutting, loose, pot hole, settlement and flushing asphalt, in which cracks are the primary distresses followed by rutting, loose and so on.(2) The main reasons why semi-rigid base asphalt pavement suffers from damages are inadequate structure capacity of surface and base course, load, temperature change and moisture intrusion, and the secondary reasons are the structure and material heterogeneity of surface and base course.(3) The mechanical analysis indicates that in order to gain good mechanical properties of pavement structure, reasonable thickness of semi-rigid materials is particularly important. The mechanical properties can be greatly improved by paving asphalt-nacadam and unbound aggregate base on semi-rigid base. Consider the construction conditions, the appropriate thickness of semi-rigid sub-base is 20cm. Sensitivity analysis of heavy load shows that asphalt-treated base asphalt pavement has a strong adaptability aiming at heavy load, suitable for high-grade highways with heavy load in China at the present.(4) Due to existence of cracks, the mechanical properties of the original structure change, resulting in stress redistribution in the structure layers. When the base layer appears cracks and its modulus do not decay, in order to avoid further damage, the proper thickness of base is more than 30cm when load is under 150kN and more than 35cm when load is 150-200kN. When cracks exist and the modulus decays, the thicker base still ensure pavement structure to keep a good load capacity and reduce the possibility of reflection crack even the cracking of base is serious.(5) For the semi-rigid base asphalt pavement in rainy environment, setting cement-treated porous base will connect the bottom asphalt layer and porous base as a continuous system, which can delay emergence of water damage and prolong the service life of asphalt pavement.
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