Investigation of the use of open-graded friction courses in Wisconsin

Abstract

As Wisconsin is looking at increasing its usage of the perpetual pavement concept, Open Graded Friction Courses (OGFC) may provide another option for use as the renewable surface layer. OGFC has historically not been used in Wisconsin due to concerns about its performance in a climate with a large number of freeze-thaw cycles. Questions also exist about the cost/benefit of these mixtures. The primary objectives of this study were to determine if the OGFC mixture can be successfully and economically used in the Wisconsin climate (Part 1), to recommend application and process procedures, and to develop appropriate mixture design and construction specifications (Part 2). The completion of Part 2 of the project was predicated on the results of Part 1. While the use of OGFC mixtures in warm southern climates has been successful, this pavement has not proven to have the same successes in the northern freeze/thaw environment. None of the states or Canadian provinces with climates that duplicate Wisconsin's use OGFC mixtures. On a routine basis, it is recommended that Wisconsin should not currently build pavements with an OGFC surface with the following two exceptions: First, if the recommended accident study indicates a large number of wet weather accidents on Stone Matrix Asphalt (SMA) pavements without a corresponding number of winter accidents, then an OGFC surface should be considered with the understanding that extra efforts will have to be made to develop deicing and snow removal procedures and to train the local maintenance personnel in these procedures. If the accidents are occurring on a Hot Mix Asphalt (HMA) pavement surface, then a SMA mixture should be used to fix the problems. Second, if in the future OGFC pavements are routinely used by another northern state, and the winter maintenance and performance of the OGFC mixture are successfully dealt with, then Wisconsin should reconsider these recommendations. Part 2 of the research project was not completed because of the questionable benefits of the use of OGFC mixtures in northern climates. Several of the references used in this report present a good summary of the current best practices for the design and use of OGFC mixtures.