In a recent study, Minnesota DOT researchers used lab and field tests to evaluate blends of recycled asphalt pavement (RAP) and virgin aggregate for use as gravel road surface layers. Maintenance costs for a 50% RAP blend and a 100% virgin aggregate surface were compared as part of an economic analysis, and two field studies analyzed the performance of blends with 15% to 80% RAP content.
Read the research report: Optimal RAP Content for Minnesota Gravel Roads, March 2019.