Evaluation and Compaction of Laboratory-Produced Recycled Asphalt Pavement in Cold In-Place Recycling

Abstract

Cold in-place recycling (CIR) is a pavement rehabilitation technique that can eliminate significant structural distresses while providing a sound, semibound base layer. Although various research groups have investigated CIR, the research has always used recycled asphalt pavement (RAP) from the field. This paper provides guidance on recreating RAP in the laboratory for CIR research. In addition, compaction metrics are modified from hot mix asphalt applications for use with CIR in the Superpave gyratory compactor. Overall, it is found that blending 25% precoated/crushed aggregate with 75% crushed/postcoated aggregate is most representative of field RAP using both limestone aggregate and syenite aggregate. In addition, five new CIR compaction metrics are evaluated to quantify the compaction behavior of CIR. These metrics show potential in quantifying workability and compactabiltiy of CIR in the lab, and consistently rank syenite RAP between the field and laboratory limestone RAPs during laboratory compaction.