Resilient Moduli of Reclaimed Asphalt Pavement Aggregate Subbase Blends

This paper investigates the resilient moduli of reclaimed asphalt pavement (RAP) and virgin aggregate blends obtained from the subbase of a segment of Route 165 in Rhode Island, U.S. The materials included RAP and virgin aggregates that were blended off-site using cold recycled RAP, as well as RAP blends that were generated in situ from full-depth reclamation (FDR). Cyclic triaxial tests were performed on compacted specimens of the RAP blends to assess their resilient modulus (MR) behavior. Selected FDR RAP blends were mixed with various stabilizer treatments including liquid calcium chloride, asphalt emulsion, or portland cement. A three-parameter material model was fit to the laboratory test data and used to interpret the MR behavior. The MR values of the untreated cold recycled RAP blends and the untreated FDR RAP blends ranged from 120 to 502 MPa and 171 to 578 MPa, respectively. The MR values of the calcium chloride-treated and asphalt emulsion-treated FDR RAP blends were within the range of the untreated FDR RAP blends, but permanent strains were higher. The MR values of the portland cement-treated FDR RAP blends were significantly higher than the untreated FDR RAP blends and had lower permanent strains.