This National Road Research Alliance (NRRA) study of MnROAD cold central-plant recycling (CCPR) sections investigated various design options for cold central plant recycling (CCPR) in low-volume road applications, where local engineers or contractors may rely on a stockpiled, single-source recycled asphalt pavement (RAP) as a quality cold-recycled layer for a paving project. Both the laboratory and field testing strove to characterize the cold-recycled (CR) layers as they performed in-situ. The field sections at MnROAD were intended to simulate low-volume road applications; therefore, the project endeavored to limit the preparation demands and characterization needs of the RAP stockpile. The laboratory tests determined that the MnROAD CCPR mixtures performed comparably to cold- recycled mixtures that were tested in other studies. Field study and observation determined that that chip-sealed CCPR lifts risk early rutting, whereas CCPR sections overlaid with 1.5" hot-mix asphalt (HMA) did not develop rutting.
This report documents the development of an electronic dataset describing field and laboratory performance of unbound bases from 106 road sections containing recycled materials in Minnesota. This dataset provides a compact view of backcalculated layer properties (from falling-weight deflection data) per road section. This view includes summary statistics on backcalculated layer properties, estimates of possible errant data in raw deflection basins, associated laboratory resilient modulus (MR) values, and other brief but insightful measures that allow MnDOT research engineers to consider which road sections to include and exclude in determining a basis for MnPAVE Flexible material inputs.
