Two-Lift Concrete Pavements Constructed Under SHRP2 Project R21 Implementation Effort

Two-lift concrete pavements use two separate lifts of concrete that are placed in a wet-on-wet process to produce a monolithic structure. Although not new, two-lift concrete pavements are an innovative approach to optimizing the characteristics of each layer and, hence, the overall pavement structure. In 2014, the Federal Highway Administration (FHWA), working in collaboration with the American Association of State Highway and Transportation Officials (AASHTO), selected two-lift composite pavements for funding under the SHRP2 Implementation Assistance Program (IAP). Under that initiative, the design and construction of three composite pavement projects featuring two-lift concrete paving were sponsored. This paper summarizes some of the key design and construction details for each of these three projects, and also provides recommendations on the general applicability and selection of two-lift concrete pavements.