ABSTRACT
Due to the increasing environmental awareness and sustainable construction concerns, new technologies have been developed in the asphalt paving industry. One of the emerging technologies is the Warm Mix Asphalt (WMA). The biggest advantages of using WMA technologies are that it can reduce the mixing and compaction temperatures of asphalt mixtures. The temperature reduction feature of WMA leads to less aging of asphalt mixtures. In this study, the field aging characteristics of WMA with Sasobit®, an organic additive, Evotherm®, a chemical additive, as well as Pen 60-70 binder were investigated. A field test section was constructed and cores were retrieved from the field periodically and asphalt mixture mechanical properties as well as binder rheological and chemical properties were evaluated to understand the aging mechanism of WMA and HMA. The results indicate that the resilient modulus results showed that WMA-S had significantly higher MR values compared to the HMA and WMA-E mixtures and the tensile strength for both WMA increased with time. Rheological tests results showed that WMA-E has a lower G* compared with HMA indicating that the lower mixing and compaction temperatures reduce the aging of the binders. However, the WMA-S has higher complex modulus, the non-recoverable creep compliance and recovery of the binder compared with HMA. The chemical characterization of the binder has revealed that the rate of aging of the WMA binders is lower than the HMA binder.

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