Initial Functional Performance of Stone Matrix Asphalt Placed on Virginia Roads in 2003 (05-1361)
Trenton Clark, Virginia Asphalt Association
Kevin Kenneth McGhee, Virginia Center for Transportation Innovation and Research
Robert A. Reid, Virginia Department of Transportation

In 2003, Virginia launched an effort to achieve longer lasting asphalt concrete surfaces on interstate and high-volume primary routes. Instead of the Virginia Department of Transportation’s (VDOT) conventional surface mixes (i.e., Superpave-designed SM 9.5 and SM 12.5), selected projects in seven of VDOT’s nine districts used stone matrix asphalt (SMA). The expanded use of SMA included the successful installation of pavements using multiple gradations (SMA 9.5, 12.5, and 19.0) and binders (PG 70-22 and PG 76-22). In this effort, many contractors (and VDOT personnel) used a very complicated hot-mix asphalt technology for the first time, and nearly without exception, they used it successfully. This paper documents the initial functional performance (i.e., roughness, friction, and texture) of SMA pavements placed during VDOT’s 2003 paving season. An overall review suggests that the pavements are meeting VDOT’s expectations. Ride quality is generally good, and there is good reason to believe it will improve as contractors gain more experience. Isolated friction problems were corrected quickly under traffic, and recent specification revisions should address a tendency to include too much liquid asphalt in some mixes. The wearing away of the asphalt film under traffic also helps to improve or eliminate glare. Finally, in spite of a minor loss of texture under traffic, the excellent overall texture of SMA should provide for very safe, low-noise surfaces.