Construction of a Precast Prestressed Concrete Pavement Demonstration Project on Interstate 57 Near Sikeston, Missouri
Chapter 9. Summary and Recommendations
The PPCP demonstration project on I-57 near Sikeston, Missouri, demonstrated the viability of PPCP for pavement reconstruction. More importantly, it allowed MoDOT and regional contractors and precast suppliers to become familiar with PPCP technology, with the hope that it will be used again in the region where it is needed most-in busy urban corridors where lane closures for pavement reconstruction and rehabilitation are severely restricted. Although the project length was relatively small in scope (~310 m [1,010 ft]), it provided a good opportunity for evaluation of the technology, and will provide an adequate test section length for monitoring long-term performance.
While similar in concept to the projects completed in Texas and California, this project presented several challenges and demonstrated several unique solutions:
- Incorporation of a crowned pavement cross section into the precast panels.
- Construction over a permeable asphalt-stabilized base.
- Use of end stressing from the joint panels (vs. central stressing).
- Use of a header-type expansion joint.
- Use of a noncontinuous keyway between panels.
- Extensive instrumentation during fabrication, construction/post-tensioning, and the first 18 months after construction.
As with previous demonstration projects, the main objective of this demonstration project was to help familiarize the local State highway agency and local contractors with the technology, while also permitting further evaluation and refinement of PPCP technology. Although the project was constructed on a section of interstate highway closed to traffic throughout the duration of construction, it demonstrated the PPCP construction process and permitted MoDOT to evaluate the viability of using it for future urban construction.
It is important to recognize that no specialty expertise was required for this project, nor should it be required for future projects. Although the precast panels were unique for this project, no special training was required by the precast fabricator to produce them. Installation of the panels on site was completed with standard equipment and did not require specially trained labor. Attention to detail was required on the part of the contractor, but this did not require any additional expertise. A specialty post-tensioning contractor completed the post-tensioning process, but in terms of post-tensioning complexity, this project was relatively simple.
It is also important to emphasize that despite the significant number of distresses observed after construction, most should have little or no effect on pavement performance. Deflection testing conducted by MoDOT confirmed that the pavement is structurally sound despite these distresses, and continued monitoring of the pavement performance over time will provide a true indication of long-term performance.
Recommendations for Future Construction
This demonstration project showed once again the adaptability of PPCP technology to specific project needs. The intent of this project was to help MoDOT and local contractors evaluate PPCP technology as a technique for rapid pavement reconstruction and rehabilitation. Future projects should focus on applying PPCP technology under circumstances where lane closures for construction are severely limited, such as busy urban corridors. This type of project will require very careful planning and preparation to ensure that none of the issues encountered on this initial demonstration project will occur during short construction window projects. As agencies and contractors become more familiar with PPCP technology, it will become a new tool for agencies to achieve the common goal of minimizing the impact of pavement construction and rehabilitation on the motoring public.
Figure 60. Photo. Finished precast pavement after opening to traffic.