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Asphalt mixture rutting may involve vertical compaction, volumetric dilation, and shear-induced lateral movement, depending on many factors. Both in the field and in the laboratory [e.g., Hamburg wheel tracker (HWT) and asphalt pavement analyzer (APA) tests], lateral movement of a mixture creates a heave region and a vertical permanent deformation along the wheel path. Typical laboratory wheel tracking tests such as HWT and APA measure the depth of pure vertical permanent deformation; field measurements measure rut depth and heave height. Currently, HWT and APA test devices are not equipped to measure heave height. The objective of this study was to develop an image-based heave height measurement methodology for HWT-tested asphalt specimens. The method can easily be extended to other wheel tracking tests, such as the APA. The study also included the generation of a three-dimensional (3D) model of HWT-tested asphalt specimens, the extraction of 3D coordinates, and the calculation of specimen heave height and rut depth. The proposed methodology was verified by comparing the calculated rut depths with laboratory-measured rut depths. The proposed methodology measured the heave height of the HWT-tested specimens with reasonable accuracy. Furthermore, a linear relationship was observed between the rut depth and heave height of the tested specimens. This research will help researchers evaluate asphalt mixture heave resistance and will extend state-of-the-art research in the domain. [ABSTRACT FROM AUTHOR]

As part of NCHRP IDEA Project 218, a new testing protocol called Three-Point Bend Cylinder (3PBC) Test was developed to speed up the fatigue characterization of asphalt mixtures. In this paper, the effects of sample geometry and air voids on the 3PBC fatigue test were investigated. The results showed that the VECD theory was successfully applied to all the selected geometries. This allowed the determination of fatigue life at any desired strain levels, temperatures, and frequencies. Based on the selected levels for each factor, specimen diameter significantly affected the 3PBC test results and fatigue lives. Specimen span length and air void content, however, did not appear to have considerable effects on the fatigue lives of the asphalt material. It should be noted that the sample variability of the 3PBC test may have softened the effects of air voids on the fatigue lives of the asphalt material. [ABSTRACT FROM AUTHOR]