Study On High Temperature Performance Of Asphalt Concrete Under Dry-wet Alternation

As the main pavement structure of highways and urban roads,asphalt pavement has been applied and studied at home and abroad.In recent years,the problem of road damage has become increasingly prominent,and water damage has become an important cause of road damage.In order to study the water loss law of asphalt pavement under actual use conditions,the high temperature deformation characteristics of asphalt mixture under different temperature,stress level and different immersion time conditions were studied by uniaxial creep test.Through the research of this paper,the following results are obtained.(1)Statistical analysis was carried out on the rainfall situation in various regions of China.Based on the rainfall conditions,the water immersion time of the wet and dry cycle was determined to be 8,12,24,48 and 96 hours respectively.(2)The water absorption rate and mass loss rate of the test piece during the dry-wet cycle were measured.The results show that the longer the water immersion time,the greater the water absorption rate.After reaching a certain time,the water absorption rate tends to be balanced.The more the dry and wet cycles are,the larger the mass loss rate of the specimen is,and the mass loss rate increases gradually with the increase of cycle times,and finally tends to balance.(3)Experiments on different temperatures and stress levels were carried out in a nonsubmerged environment,uniaxial creep test under dry and wet cycles.The results show that when the stress level exceeds 0.4MPa,the nonlinear viscoelastic deformation characteristics appear at 40°C.The viscoplastic strain of the asphalt mixture increases with the number of dry and wet cycles,and the viscoelastic deformation characteristics also.The test results show that the dry and wet cycle has a certain influence on the high temperature performance of the asphalt mixture.