| SMA asphalt mixture has been widely used in modern high-grade road construction for its excellent rutting resistance,skid resistance and wear resistance.In recent years,people have been adding various admixtures to enhance their road performance to meet the growing demand of traffic load.For the fresh SMA asphalt mixture,various admixtures have improved its road performance to varying degrees,but for the SMA asphalt mixture with service life of several years or even ten more years,people should conduct comprehensive research on its long-term performance.Therefore,choosing appropriate admixtures to mix into SMA-13 asphalt mixture and analyzing the influence of admixtures on the long-term performance of asphalt mixture will help to determine the maintenance cycle and provide theoretical reference for the selection of admixtures in the process of road construction and maintenance.Marshall design method was used to design the mix proportion of basalt fiber SMA-13,lignin fiber SMA-13 and SMA-13 asphalt mixture mixed with anti rutting agent and lignin fiber.The mineral composition and optimum oil stone ratio of the three gradations were determined.The proportion of basalt fiber,lignin fiber and anti rutting agent was 0.4%,0.3%and 0.5%respectively,and the best oil stone ratio was 5.8%,6.0%and 6.0%respectively.Rutting test,uniaxial penetration test,low temperature beam bending test and immersion Marshall test were used to test the road performance of three asphalt mixtures.The test results showed that compared with the traditional lignin fiber SMA-13 asphalt mixture,the addition of anti rutting agent can effectively improve the high temperature performance of SMA-13 asphalt mixture,but not the low temperature performance and water stability of asphalt mixture;The addition of basalt fiber can significantly improve the high temperature stability and low temperature crack resistance of asphalt mixture,but the improvement of water stability is less.The aging test is selected to treat the asphalt mixture and simulate the actual state of asphalt pavement after a certain service life.The rutting test and uniaxial penetration test were used to analyze the high-temperature performance of asphalt mixture.The low-temperature small beam bending test,ideal-ct cracking test and semicircle bending tensile test were used to study the cracking resistance,crack extension and development rate of the mixture.The immersion Marshall test was used to analyze the high-temperature performance of asphalt mixture This paper analyzed the water stability of asphalt mixture and the influence of admixtures on the long-term performance of asphalt mixture.The test results showed that the long-term high-temperature resistance of asphalt mixture mixed with anti rutting agent and lignin fiber was poor,the high-temperature stability decayed rapidly with the increase of time.The low-temperature performance,water stability performance and anti cracking performance were also weakened to varying degrees in the aging stage.While the addition of basalt fiber could greatly improve the long-term high temperature resistance of asphalt mixture,which had a certain inhibition effect on the crack development,but had little effect on the long-term water stabilityThe research results of this paper can provide technical reference for the selection of SMA-13 asphalt pavement admixture,and have good application value. |
