Evaluation of low-temperature properties of long-term-aged asphalt mixtures

Asphalt aging is an important factor to cause pavement cracking. Currently, researchers primarily conduct ageing tests on asphalt binder to study the ageing effect on asphalt pavements. However, the ageing effect is also dependent on the air void and aggregate properties. Therefore, this paper conducted ageing tests on asphalt mixtures to account for the influences of ageing effect on in-situ pavements. The LTAC properties of both plain asphalt mixtures and polymer-modified asphalt mixtures were investigated. Laboratory flexural and flexural creep tests were conducted on the beam specimens of asphalt mixtures, including those subjected to the short-term oven ageing and others subjected to the long-term oven ageing. Results indicate that polymer-modified asphalt mixtures have superior LTAC performance than that of plain asphalt mixtures. The long-term ageing has more significant effect on the LTAC properties than short-term ageing. The long-term oven ageing test is recommended to evaluate LTAC properties of the aged in-situ asphalt pavement. A performance index for the evaluation of the LTAC properties of the aged asphalt pavements was proposed.