Validation of the Stiffness Raveling Mechanism Test for Cold In-Place Recycling

Cold In-place Recycling (CIR) is a rehabilitation treatment that restores a flexible pavement structure. While there has been significant research in design and performance testing of CIR, there is limited consideration of performance during construction. This research validated the Stiffness Raveling Mechanism Test (SRMT) in the lab and in the field, as an inexpensive, easy way to quantify the curing of CIR. In the lab, CIR and Hot Mix Asphalt showed lower rebound heights at higher air voids, higher testing temperatures, and moisture conditioning. In the field, the SRMT had a good correlation to density during compaction, but the data was not accurate enough to establish roller pattern recommendations. The SRMT had a maximum rebound after approximately 20 h of curing and then saw a small decrease over a five-day period, and was able to differentiate emulsified asphalt types based on cohesion gain. Finally, based on the 24-h field validation, it is recommended that a rebound height of 305-356mm (12–14 inches) could be specified for return to traffic.