Asphalt-Aggregate Interactions in Hot Recycling.

This report summarizes results of an investigation of asphalt aggregate interactions in hot recycled systems. Materials used in the research included a severe stripping aggregate and a nonstripping aggregate. Both were evaluated using the Lottman 70 percent retained tensile strength criteria. Additional materials included a 4060 RAP new aggregate system, one virgin asphalt, two RAP recovered binders, one modifier or recycling agent, and two blends. The modifier was selected using a recently developed specification involving physical, composition, and solubility properties. Aggregates were evaluated for surface area, bulk composition, water soluble ions, cation exchange capacity, gradation, and specific gravities. Binders were tested for physical properties and composition properties using a modified Clay-Gel procedure, and compatibility properties using a modified Heithaus procedure. Keywords Asphalt aggregate interactions, Hot recycling, Reclaimed asphalt pavement RAP, Aged binders, Modifier, Recycling agent, Recycled blends, Heithaus, Compatibility, Clay-Gel composition, Adsorbed surface ions, Water soluble ions, Aggregates, Surface area, Porosity, Dry tensile strength, Wet tensile strength, Dry resilient modulus, Wet resilient modulus, Tensile strength ratio, Resilient modulus ratio, Microcalorimetry, Bond energy, Correlation, Recycling guidelines.