TESTING RAP MATERIALS FOR OVERLAY DESIGN STANDARDS

Cold-mixed, cold-laid (CMCL) rehabilitation or cold recycling is a technically promising and cost effective method for improving distressed asphalt pavements. Unlike hot mix recycling, cold recycling lacks field and laboratory performance data. Also, there is no widely accepted CMCL design and testing standards available. This study has generated useful field and laboratory data on pavement overlay constructed with 100% recycled asphalt pavement (RAP) and the CMCL technique. The laboratory tests conducted in this study include physical property, strength and performance-related tests. While property tests include moisture content, gradation, specific gravity, emulsion content, aggregate properties, coating and adhesion; strength and performance tests include resistance, indirect tensile strength, moisture-induced damage susceptibility, and rutting. In addition, two field case studies are conducted; one overlay job was quite successful but the other exhibited relatively poor performance. Causes of differential performance are examined. BACKGROUND