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dc.contributorLytton, Robert L.
dc.creatorLuo, Xue
dc.description.abstractFatigue cracking is one of the most common distresses of asphalt pavements, whereas healing is a counter process to cracking which alleviates cracking damage and extends fatigue life of asphalt pavements. Most of existing methods to characterize fatigue cracking and healing are generally empirical or phenomenological in nature, which does not satisfy the need to develop mechanistic-based pavement design methods. The objective of this study is to characterize fatigue cracking and healing of asphalt mixtures using an energy-based mechanistic approach. A controlled-strain repeated direct tension (RDT) test is selected to generate both fatigue cracking and permanent deformation in an asphalt mixture specimen. Fatigue cracking is separated from permanent deformation from a mechanical viewpoint. The development of fatigue cracking is described by the evolution of the damage density and the increase of the average crack size with the increase of loading cycles. A creep and step-loading recovery (CSR) test is designed to measure the internal stress in the recovery phase of an asphalt mixture specimen. The internal stress and the strain measured in the recovery phase are used to conduct the mechanistic analysis of recovery and healing of the asphalt mixture specimen. Then healing is described using the decrease of the damage density and average crack size with time. Different types of asphalt mixtures produce distinctly different fatigue cracking and healing characteristics. The effect of mixture composition, temperature, and aging are evaluated using the approach above. The entire series of tests for fatigue, permanent deformation and healing can be completed in one day, with the healing part requiring only a matter of minutes. The methods proposed in this study characterize fatigue cracking and healing of asphalt mixtures using its essential cause and effect relationship.
dc.subjectasphalt mixtures
dc.subjectcrack growth
dc.subjectdissipated pseudo strain energy
dc.subjectrecoverable pseudo strain energy
dc.subjectdissipated strain energy
dc.subjectrecoverable strain energy
dc.subjectenergy-based mechanistic approach
dc.subjecttrue stress
dc.subjectinternal stress
dc.subjectdamage density
dc.subjectaverage crack size
dc.subjectnumber of cracks
dc.titleCharacterization of Fatigue Cracking and Healing of Asphalt Mixtures

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