University of California Pavement Research Center

A pilot project for the inclusion of recycled asphalt shingles (RAS) in hot mix asphalt (HMA) was built on State Route 49 in El Dorado County in November 2021. Four mixes were included in short test sections: (1) a control mix with no RAS or recycled asphalt pavement (RAP), (2) a typically used mix with 10% RAP that was also used for construction of the rest of the overall project, (3) a mix with 3% RAS, and (4) a mix with 10% RAP and 3% RAS. This technical memorandum presents the laboratory test results from plant mix produced for job mix formula (JMF) verification and from two quality assurance (QA) samples taken during test section construction as well as observations of plant production and construction. The results showed that the mixes submitted for JMF verification and tested as part of QA all met the two performance-related specifications. Most of the QA samples had binder and mix testing results that were similar to or better than those of the JMF verification samples, though there were exceptions. There were no major problems during production or placement of the mixes. The existing roadway has highly variable thicknesses of remaining HMA after milling, and the remaining original HMA has transverse, wheelpath, and block cracks.