PUSHING THE BOUNDARIES

For years engineers have designed bridges, buildings, and other vertically oriented infrastructure using precast concrete, but only recently have researchers begun exploring the feasibility and potential benefits of applying this technology ongrade in pavement construction. This article explores the current and potential uses of precast prestressed concrete in pavement applications, notably in Texas and in California projects. The authors describe the three specific types of panels that make up a precast prestressed concrete pavement: joint panels, central stressing panels, and base panels. The author also discusses the benefits of using prestressed concrete, primarily the ability to reopen the pavement to traffic almost immediately after placing the panels. The author reviews the Texas and California demonstration projects, then summarizes the activities at three additional sites in Missouri, Texas, and Indiana. The author concludes that although precast prestressed concrete is currently more expensive than conventional cast-in-place pavement, proponents argue that the reduction in user costs, such as traffic congestion, fuel consumption, and lost work time, will support the use of this technology for certain situations.