Design, Construction, and Performance of New-generation Open-graded Friction Courses

Open-graded friction course (OGFC) has been used by several state departments of transportation (DOT) since 1950. While many DOTs report good performance, many other states stopped using OGFC due to unacceptable performance and/or lack of adequate durability. A vastmajority of the states reporting good experience use polymer modified asphalt binders and a relatively coarser aggregate gradation compared to the other states reporting unsatisfactory performance. Obviously, there is a need to develop an improved mix design procedure to help the highway agencies in successful use of OGFC. The primary objectives of this study are to evaluate the performance of OGFC in the laboratory with different gradations and types of additives, and recommend a rational mix design procedure for the new-generation OGFC mixes. Additionally, the construction and performance of six OGFC pavements (constructed prior to this study) are discussed. These mixes generally meet the requirements for gradation band and Cantabro abrasion recommended in the new mix design system.Several polymers and fibers were used in OGFC mixes. The mixes were evaluated for draindown, permeability, Cantabro abrasion, rutting, and moisture susceptibility. A tentative mix design system for the coarse new-generation OGFC has been recommended. Based upon the evaluation of six OGFC field pavements, it has also been shown that OGFC mixes meeting the new mix design requirements are constructible and have exhibited good performance