Key Considerations

Before installing precast pavement, the condition of the existing pavement should be assessed to determine the need for additional repairs or rehabilitation, such as drainage improvements and foundation repairs. Designers should determine the cause of distress to ensure the repair fixes the problem as well as prevents it from reoccurring. Precast concrete pavement systems are not a remedy for foundation problems, so the type, condition, and thickness of the existing base and subbase layers should be assessed.

In some cases, it is beneficial to design precast panels with increased structural capacity without increasing the panel thickness. This can be done by prestressing and/or post-tensioning the panels.

The presence of utilities—such as drainage structures, water and sewer pipes, natural gas and electrical pipes, and conduits—must be considered as well. Some of these utilities must be easily and regularly accessed, requiring penetration in the pavement surface in the form of manholes or inlet grates. Others don’t require access but must be reached through excavation for repair. There are precast concrete pavement systems features that exist to accommodate these utility needs, sometimes more easily than cast-in-place pavements can.

Using precast concrete pavement systems to replace flat, rectangular cast-in-place panels on straight pavement sections is straightforward. When placing precast panels in horizontal curves and transitions to elevated areas, nonplanar, trapezoidal and other-shaped panels may be needed. Those require special precasting forms and a need for them must be clearly specified.