This report presents the findings from an eight-year performance evaluation of eight cells (Cells 16-23) built at the Minnesota Road Research Facility (MnROAD) in 2008. The constructed cells were used for two performance evaluation studies of: 1) unbound base materials (i.e.; recycled asphalt pavement (RAP); recycled concrete aggregate (RCA); and taconite) and Class 5 aggregate as the road base material and 2) surface materials that include warm mix additives (WMAs); RAP; and different binders with different performance grades. The eight cells were tested via a surface distress survey; rutting tests; falling weight deflectometer tests; international roughness index (IRI) tests; and friction tests. Disk-shaped compact tension (DCT) tests also were performed using the mixture samples; and the performance of the unbound base materials (Cells 16-19) was evaluated using light-weight deflectometer (LWD); dynamic cone penetrometer (DCP); and gradation tests. After eight years of service (approximately 5.6 million equivalent single-axle loads); the cells remained in good condition in terms of their resistance to surface distresses; rutting; stiffness; IRI values; and friction. Consequently; it was difficult to compare the performance of the various unbound materials and mixtures. The unbound recycled materials and taconite performed as well as the Class 5 aggregate base material in terms of the gradation; DCP; and LWD test results. All mixture types; regardless of RAP content; binder grade; or the presence of WMA; exhibited similar performance.
