NRRA: Determining Pavement Design Criteria for Recycled Aggregate Base and Large Stone Subbase Status: CompleteReport Date: 07/13/2021 Summary: Although recycled pavement materials have been used in roadway base layers for many years, a specific design method does not exist that describes how to build roadways with these materials. Many state Departments of Transportation assume recycled base materials behave similar to base layers built with conventional virgin aggregates. There is a similar lack of an existing design methodology for pavement systems built with a large stone subbase (LSSB). This National Road Research Alliance-sponsored study will help optimize the use of recycled materials and LSSB in pavement systems and lead to more consistent specifications between transportation agencies. Other benefits: virgin material cost savings from the use of recycled materials; longer pavement service life, resulting in reduced life cycle costs; and conservation of natural resources resulting in reduced environmental impacts. Another outcome will be a pavement design specification that can be immediately implemented by members of the NRRA. Final Deliverables: Report #NRRA202103 Appendix #NRRA202103A Related Materials: Related Research: