The asphalt paving industry is facing two major challenges. These includeincreased demands for environmentally friendly paving mixtures and increasing costs of raw materials. To address these challenges, it has been suggested to incorporate WMA technology additives and more Recycled Asphalt Pavement (RAP) into new HMA mixtures. In this study, the influence of the dose of two WMA additives (Advera and Sasobit) on the composite binder properties, mixture workability, and mixture durability was investigated. TwoSuperpave mixtures, a 12.5mm with 10% RAP and a 19.0mm with 25% RAP, wereused for this study. Binder testing showed that the addition of Sasobit at a dose of 1.5% and 3.0% by weight of the binder changed the performancegrade of the binder and decreased the binder viscosity. The addition of Advera at dosages of 0.1% and 0.3% by weight of mixture did not change theperformance grade of the binder and only marginally changed the binder viscosity. Workability testing on the mixtures showed that both WMA additives improved the workability of the mixtures containing RAP at any of dosages tested. Durability testing showed that all the WMA additives tested at any dose increased the moisture susceptibility of the mixture. This indicated that for particular WMA additives anti-strip may be required in orderto produce a durable mixture. Furthermore, durability testing may be an integral step when developing a mix design procedure for mixtures with WMAadditives.
Abstract