Evaluation of warm mix open graded friction course mixtures

The goal of this study was to evaluate Evotherm(TM) (a chemical package) and foaming (a water-injection method) warm mix asphalt (WMA) technologies to determine their effectiveness in producing high quality open graded friction course (OGFC) mixes. Specifically, this study focused on the effect of the removal of stabilizing additives (fibers and polymers) on the optimum binder content and performance of WMA OGFC mixtures. By focusing on additive removal, this study attempted to evaluate practical production concerns and the possible benefits of WMA technologies combined with OGFC.;The Evotherm(TM) WMA and foaming WMA mixes were compared to traditional HMA OGFC by evaluating four main mix design criteria: draindown, moisture susceptibility, permeability, and abrasion resistance. Overall, 10 different mix designs were tested and evaluated for use in OGFC pavements. Both volumetric and performance properties were analyzed to assess the performance of each mix design. The results suggested that WMA technologies have the ability to enable the removal of fiber from OGFC mix designs without significant draindown and to improve the performance properties of OGFC mix designs. This study suggests that there is a high potential for the use of warm mix technologies in OGFC.