Field Evaluation of Porous Friction Course for Noise Control (05-0508)**
Rebecca S. McDaniel, Purdue University
William D. Thornton, Purdue University

In 2003, the Indiana Department of Transportation allowed a test section of Porous Friction Course (PFC) to be placed on I74 east of Indianapolis. This paper summarizes the design, construction and early performance of that surface compared to an adjacent SMA surface and a conventional Superpave HMA surface. All three mixes included steel slag aggregate and a PG76-22 binder. The PFC was designed at 18-22% air voids to provide a permeable surface. Noise measurements were made on all three surfaces using both the pass-by and close-proximity methods. The three surfaces were also evaluated in terms of surface texture using the Circular Texture Meter and friction using the Dynamic Friction Tester and towed friction trailer. Splash and spray were judged qualitatively. The early performance indicates that the PFC produced significantly lower noise levels, higher surface texture and friction, and reduced splash and spray compared to the other two surface types.