Evaluation of warm mix asphalt containing recycled asphalt shingles

Advances in asphalt materials have led to the incorporation of higher amounts of recycled asphalt materials in mixtures that can be produced at reduced temperatures. Two demonstration projects were constructed to assess the performance of mixtures that use warm mix asphalt (WMA) and recycled asphalt shingles (RAS) at reduced temperatures. WMA mixes were produced at 120 °C. Eighteen pavement sections were monitored each year after construction. Performance tests were conducted on all mixes to measure material properties at a range of temperatures. Additional tests were conducted for one of the field projects to show the influence of increasing RAS on moisture susceptibility. Results indicate that WMA can successfully be used with a RAS mixture. Benefits of adding additional RAS include improvement in rutting, stripping inflection point (SIP), and higher or similar dynamic modulus values at increased test temperatures.