Effects Of Environmental Changes On Ultimate Axle Load For Semi-rigid Asphalt Pavements

Economic prosperity in China has boosted the development of transportation but at the some time some reasons bring more and more heavy-load, overload phenomena. Due to once only load action by heavy load and overload, damage of asphalt pavement has become increasingly serious and continues to deteriorate influenced by environmental action.Based on summary of research and study results home and abroad, in terms of climate characteristics of asphalt pavement in China, aimed at once damage of pavement structure caused by heavy load and overload in China, the effect of environmental changes on ultimate axle load for semi-rigid asphalt pavements was explored in this paper. Under different environmental temperature, visco-elasticity mechanical property of asphalt mix is taken into account and modulus of asphalt layer is determined by using the relationship between stiffness modulus of asphalt and asphalt mix. Under various humidity conditions, considering sensibility of soil base modulus to water, it is confirmed that ultimate axle load is flexural-tensile stress of bottom layer, which equals to load value when material of each structure layer is tensile by using BISAR software to calculate.It indicates by analysis in theory that temperature is an important factor to influence ultimate axle load of asphalt pavement. Ultimate axle load is decreased with increase of pavement temperature; the higher the temperature of pavement, the less load action supported by pavement structure and the easier once load damage of pavement occurs. Humidity is another important factor to influence ultimate axle load of asphalt pavement. The better the humidity of soil base, the larger the modulus of resilience, and the greater the ultimate axle load. The pavement thickness also influenced ultimate axle load of asphalt pavement. The more thickness of surface layer and base-course or subbase in asphalt pavement, and the greater the ultimate axle load.According to calculated pavement structure in this paper, with the temperature of pavement is increased -30℃from to 60℃, the limit axle load is declined by 24%, decreased by 46% to maximum. When the modulus of soil base is increased from 10MPa to 80MPa, limit axle load is leveled by 51% in minimum,68% in maximum.