Development of a Laboratory Testing Framework to Estimate Reclaimed Asphalt Pavement Binder Performance Grade without Solvent Extraction and Recovery

This study introduces a laboratory testing framework for estimating the performance grade (PG) of asphalt binders in reclaimed asphalt pavement (RAP) without using solvent extraction and recovery. The study was conducted in two phases: Phase I aimed to identify suitable performance tests for assessing RAP binder stiffness using laboratory-prepared artificial RAP, and Phase II focused on validating these selected tests for estimating binder PG of field RAP. In Phase I, the indirect tensile asphalt cracking test (IDEAL-CT), high-temperature indirect tensile test (HT-IDT), and Dongre workability test were conducted on artificial RAP samples prepared with different asphalt binders and laboratory aging conditions. Among these, the IDEAL-CT and HT-IDT exhibited a strong exponential correlation with the extracted RAP binder PG and were subsequently evaluated in Phase II for their feasibility and accuracy in estimating binder PG for three distinct field RAP sources using the proposed testing framework. The framework required the preparation of three re-mixed RAP samples for each source, prepared by mixing the post-ignition aggregates with three asphalt binders of known PG at the same asphalt content as the field sample. All the re-mixed and field samples underwent IDEAL-CT and HT-IDT testing, with results analyzed to determine the estimated PG of the field RAP binder. Using indirect tensile test (IDT) strength from HT-IDT and peak load (P max ) from IDEAL-CT, the framework produced reliable PG estimations for two out of three field RAP sources, highlighting its promise as a non-hazardous alternative to solvent extraction and recovery for RAP binder quality characterization.