Evaluating the Effect of Warm Mix Asphalt Technologies on the Moisture Characteristics of Asphalt Binders and Mixtures

摘要

The purpose of this study was to evaluate the effect of Warm Mix Asphalt (WMA) technologies on themoisture susceptibility of a mixture and the adhesion characteristics of the asphalt binder used in it. A 9.5mm Superpave mixture designed with a PG64-22 was used as the control mixture. Four different types ofWMA technologies were evaluated: Advera, Evotherm, Sasobit, and SonneWarmix.The effect of each WMA technology on the moisture susceptibility of the mixture was evaluatedat three aging times and three aging temperatures using the Hamburg Wheel-Tracking Device. A liquidanti-strip and hydrated lime were added to any mixture that failed the HWTD to determine if they couldcorrect the failure. Because the moisture susceptibility of a mixture is related to failure in the adhesivebond between the binder and aggregate, the impact of the WMA technologies on the adhesioncharacteristics of the asphalt binder was evaluated using a pull-off test called the Bitumen Bond Strength(BBS) test.The HWTD test results indicated that the moisture resistances of all mixtures improvedsignificantly with an increase in aging time or temperature. Mixtures aged at longer times combined withhigher aging temperatures exhibited the best performance. The addition of the anti-strip agents improvedthe HWTD results. The BBS showed that only Sasobit had a significant effect on the pull off tensilestrength of the binder, although only under dry conditions. Overall, no correlation between the BBS andthe HWTD was found.