Optimal RAP Content for Minnesota Gravel RoadsStatus: CompleteReport Date: 03/13/2019 Summary: Researchers examined mixtures of recycled asphalt pavement (RAP) and aggregate for new gravel road surface layers in the lab and in the field. Test results did not align perfectly, and field results were somewhat uneven. However, findings suggest that mixtures with 70 percent RAP content can reduce dust generation and after a year of service can match all-aggregate gravel road performance in terms of strength, but with a smoother ride. Final Deliverables: Report #2019-11 Research Summary Related Materials: Study Suggests 70 Percent RAP for Minnesota Gravel Road Surfaces - (Blog Post) Related Research: