Case Study of 100% RAP Rejuvenated Cold-Mix Asphalt: Construction and Short-Term Performance of Pavement Overlays

Abstract

This case study evaluates the construction methodology and short-term field performance of a cold-mix asphalt overlay produced with a bio-based rejuvenator and 100% reclaimed asphalt pavement (RAP) on a roadway in Florida. The overlay was constructed in two stages over consecutive days, allowing for modification of construction parameters between phases. The Stage 1 construction used a 0.8% rejuvenator dosage and vibratory compaction, while the second stage employed a reduced 0.5% dosage and enhanced compaction using pneumatic and utility rollers. Field performance was assessed using pavement condition index (PCI) ratings at 1 day, 17 days, and 8 months post construction. Early surface distresses primarily exhibit low-severity weathering and raveling, likely due to elevated RAP moisture content and lack of a curing period before the road was open to traffic. Despite these, PCI ratings remained high. By 8 months, a slight decline in PCI was noted across all sections, although the Stage 2 section maintained higher values, indicating improved durability due to construction modifications. Edge zones showed more deterioration than the center of the roadway, and sections over a gravel subbase performed better than the sections over a subgrade soil. Based on these findings, proper moisture control, compaction sequencing, and applying surface treatment are recommended to improve field performance, while ongoing monitoring is encouraged to assess long-term durability. Overall, cold-mix asphalt overlay with 100% RAP and bio-based rejuvenator demonstrates a feasible and low-cost solution for low-volume roads application in warm and wet climate zone.