This study presents an experimental investigation on the rutting resistance of permeable asphalt mixes (PAM). In practice, PAM, also referred to as Open-graded friction courses (OGFC) or permeable friction courses (PFC), are prone to permanent deformation due to heavy vehicle traffic loads and a weak mineral skeleton caused by their high air void contents. Consequently, the draining capacity of the PAM is diminished making the roads unsafe particularly in wet conditions. Hence, the rutting mechanism of PAM is evaluated through three laboratory tests: dynamic modulus, flow number, and Hamburg wheel tracking test (HWTT). The laboratory samples were prepared and compacted considering four air voids (AV) contents: 18%, 20%, 22% and 25%. From the HWTT, a comparative analysis was conducted using X-ray computer tomography (X-ray CT) images obtained before and after the tests in order to investigate AV distribution due to rutting. Results from the tests indicated that an increase in AV content reduced the rutting performance of PAM, as well as higher AV content led to larger mix densification and thus a deeper rut was achieved. Similar results were attained from the analysis of the X-ray CT images, nevertheless, a larger AV densification was observed in the upper part of the samples beneath the developed rut, which can lead to further weakening the mineral skeleton and progress of other several distress that typically develop for PAM.