<p>Rutting is a severe distress that significantly compromises the durability and service life of asphalt pavements. To clarify the creep failure mechanism of bitumen and enable accurate and practical failure time prediction, this study investigated the influence of viscoplastic deformation on the rutting performance and failure behavior of bitumen through long-term creep tests. For the first time, an Eyring’s activated flow model was applied in conjunction with the time–temperature superposition principle to accurately characterize the viscoplastic flow behavior of bitumen. A novel rutting failure criterion based on the unrecoverable deformation observed in the creep and recovery test was proposed to predict the rutting failure of bitumen under varying stress and temperature conditions in long-term creep tests. The consistent relationship between the plastic creep rate and failure time observed in both bitumen across varying temperatures indicates that the rutting failure is predominantly governed by a plasticity-controlled mechanism. Eyring’s activated flow rule effectively captures the evolution of viscoplastic flow in bitumen under varying stress and temperature conditions, while the time–temperature superposition principle proves effective in developing master curves across a wide temperature range. The proposed failure criterion demonstrates high accuracy in predicting the failure time of long-term creep tests. Moreover, the parameters governing bitumen failure were found to be insensitive to temperature variations. This study provides a robust foundation for developing predictive tools that remain reliable under diverse environmental conditions.</p>