| Whether or not withstand load, the performance of pavement materials will change over time, particularly the aging performance of asphalt pavement. Due to aging, the deformation of asphalt pavement is weakened and the pavement is easy to crack under the temperature stress and vehicle loads, even net crack. These exacerbate the destruction of the pavement and directing affect the usage performance and life of pavement. Therefore, the study on aging performance of asphalt pavement has important practical significance to improve its usage quality and life.According to the composition structure and strength theory of asphalt mixture, asphalt mixture is complex and multi-level spatial structure. Only from the aging of asphalt itself, we study and evaluate the aging performance of asphalt mixture that is obviously not enough and is wrong. So we should synthetically consider of the effect of interaction between asphalt and mineral aggregate, and the mixture structure to the aging of asphalt mixture.This paper is relying on youth teachers'research startup fund project of Jilin University "The study on aging performance of asphalt mixture in high-grade highway asphalt pavement", the research object is SAC 13 (Stone Asphalt Concrete) and AC 13 (Asphalt Concrete). Referring to "Standard Test Methods of Bitumen and Bituminous Mixtures for Highway Engineering" (JTJ 052-2000), design and test. Conduct dynamic indirect tensile stiffness modulus test on nonaging and aging specimens using COOPER machine. Through analysis and study of test results, in this paper the conclusions mainly include:(1) In this premise to reach the same target horizontal deformation of (5±2)μMn, stiffness modulus of four graded asphalt mixture after aging is continuously increasing with aging time extended. The rate of growth is fast at the early stage, followed begins to be relatively slow. The size relation of stiffness modulus for the four graded asphalt mixture is:in aging temperature of 145℃and 165℃conditions, SAC13-1>AC13>SAC13-2>SAC13-3; in aging temperature of 185℃conditions, SAC13-1>AC13>SAC13-3>SAC13-2. Stiffness modulus of SAC13-2 and SAC 13-3 is almost equal among them.(2) In different aging temperature conditions, with aging time extended stiffness modulus is continuously increasing, aging coefficient is continuously increasing, it shows that the degree of ageing deepens continuously. The aging rate of SAC 13-1,SAC 13-2,SAC 13-3,AC 13 four gradation asphalt mixture is relatively fast at the initial stage, has gradually slowed down as the degree of ageing deepens, and when aging temperature is higher, this trend is more notable. The sequence from strong to weak of their anti-aging properties is:in aging temperature of 145℃and 165℃conditions, SAC13-3>AC13>SAC13-2>SAC13-1; in aging temperature of 185℃conditions, SAC13-3>SAC13-2>AC13>SAC13-1.(3) Research shows thatαT-T curve of SAC13,1 SAC13-2,SAC13-3,AC 13 four gradation asphalt mixture is consistent with the form of Arrhenius formula. Ts and Tg of these four gradation asphalt mixture is achieved. It proves that WLF formula of the time-temperature conversion is applicable for these four gradation asphalt mixture in the range of aging temperature from 100℃to 200℃.(4) The shape of stiffness modulus master curve of asphalt mixture after aging is similar and presents approximate"S"in the semi-rectangular coordinate system, whether different aging temperature or different gradation type. It is conform to the form of Sm=α+bect, and has this kind of phenomenon:a>0,b<0,c<0. For the same grade asphalt mixture, the higher the aging temperature, the bigger the value of a and the smaller the value of b and c,so the greater the stiffness modulus of asphalt mixture after aging.(5) Establish the decay models of SAC 13-1,SAC13-2,SAC13-3,AC 13 four gradation asphalt mixture under 145℃,165℃,185℃three kinds of aging temperature that aging performance changes with aging time, they are conform to the form ofλ=η1+η2eη3t, and have this kind of phenomenon:η1>0,η2<0,η3< 0.
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