Cold in-place recycling (CIR) is a process in which 3 to 4 inches of the existing asphalt pavement layers are pulverized, mixed with a recycling agent, and repaved in place. It provides agencies with cost-effective and environmentally friendly pavement maintenance and rehabilitation options for aged asphalt pavements. The TRB National Cooperative Highway Research Program's NCHRP Synthesis 569: Practice and Performance of Cold In-Place Recycling and Cold Central Plant Recycling compiles and documents information regarding the current state of practice on how CIR and cold central plant recycling (CCPR) technologies are selected, designed, constructed, and evaluated by state departments of transportation (DOTs).
