PERFORMANCE OF RECYCLED ASPHALT CONCRETE OVERLAYS IN SOUTHWESTERN ARIZONA

Recycled asphalt concrete overlay is a routine rehabilitation strategy for most highway agencies. In 1981 the Arizona Department of Transportation constructed an experimental asphalt concrete overlay project on Interstate 8 in southwestern Arizona. The project consisted of eight test sections comparing long-term performance of recycled and virgin asphalt concrete overlays in an arid climate. Mays meter roughness, Mu meter skid number, and percentage cracked data were collected on different test sections over the service life of the project. A visual distress survey was conducted on each section at the end of service life. Rut depth and falling weight deflectometer measurements were also taken before rehabilitation of the 1981 project. Analysis of roughness, skid, and cracking data indicates that the recycled and virgin asphalt concrete overlays have performed similarly. The poor condition of one virgin overlay section at the end of the service life appeared to be caused by weaker subgrade support. The thicker overlays performed better than did the thinner overlays. Considerable rutting was observed on the thicker overlay sections partly because of densification of asphalt concrete mixes under traffic load. The average annual maintenance costs for different test sections were similar.