Evaluation of Asphalt Mixture Laboratory Long-Term Aging Methods for Performance Testing and Prediction

Abstract

Aging has long been recognized as a major distress mechanism for asphalt concrete and, by extension, asphalt pavements. Aging causes the material to stiffen and embrittle, which leads to a high potential for cracking. Although a significant amount of effort has been placed on understanding the aging process of asphalt binder, less effort has been put forth to develop laboratory aging procedures for producing aged mixture specimens for performance testing. An optimal laboratory conditioning procedure to simulate long-term aging for performance testing and prediction is required in order to integrate the effects of long-term aging in pavement prediction models and other mechanistic design and analysis methods. In this study, oven aging and pressure aging vessel aging are applied to both loose mix and compacted specimens in order to evaluate and select an aging method to simulate long-term aging for performance testing and prediction. The selected method must be able to maintain specimen integrity in order to be used for performance testing and prediction. Efficiency, practicality, and versatility also are considered in evaluating the aging methods. The results demonstrate that loose mix aging in an oven is the most promising aging method to produce mixture specimens for performance testing in terms of efficiency, specimen integrity, versatility, and cost.