Case Study of High-Traffic In-Place Recycling on U.S. Highway 49: Multiyear Performance Assessment

This paper documents the in-place recycling of a high-traffic project (12,000 vehicles per day) on U.S. highway 49 (US-49). Sections built included asphalt emulsion–stabilized cold in-place recycling (CIR), portland cement–stabilized CIR, cement-stabilized full-depth reclamation (FDR), and traditional construction. This paper’s objective is to present a case study of US-49 construction and performance through approximately 4.5 years of service. Performance was characterized by a distress survey, cored properties, and falling weight deflectometer testing. In particular, findings demonstrated performance and economic trade-offs between cement CIR and emulsion CIR, which could be directly applied to planning decisions. Emulsion CIR exhibited sufficient rutting capacity but reserve cracking capacity, at higher costs relative to cement CIR. Cement CIR, however, was more economical and exhibited excess rutting capacity but not excess cracking capacity. Because there is little need for reserve capacity of one distress when other distresses are past capacity, this paper proposes balanced binder blends (examples might include 2.5% emulsion with 2% cement, or 3% emulsion with 1.5% cement) for future consideration because they can provide sufficient capacity for multiple distresses while balancing economics.