Precast Prestressed Concrete Pavement For Reconstruction And Rehabilitation Of Existing Pavements

This TechBrief describes the application of precast prestressed concrete pavement for new construction and for rehabilitation of existing asphalt and concrete pavements. The background of the development of precast prestressed pavement technology is briefly summarized. The details of several field trials of this innovative technology are presented, and recommendations for ensuring successful precast prestressed concrete pavement installation are provided.

"TRB's second Strategic Highway Research Program (SHRP 2) Report S2-R05-RR-1: Precast Concrete Pavement Technology reviews the available precast concrete pavement (PCP) systems; summarizes PCP applications; and offers suggested guidelines for the design, fabrication, installation, and selection of PCP systems. " -- Publisher's description.

State Highway Agencies are continually seeking new techniques for expedited pavement construction that will permit reconstruction and rehabilitation of existing pavements with minimal impact on the traveling public. Precast prestressed concrete pavement (PPCP) is one such technique which has been demonstrated in recent years to meet this need. Precast panels can be produced well in advance of construction, stockpiled, and hauled to the site for installation as needed. PPCP can be constructed during non-peak travel times, such as overnight or during weekend closures, in order to minimize lane closures and associated user delays. This report documents the construction of a PPCP demonstration project on Interstate 57 Near Sikeston, Missouri. This work was conducted under an effort by FHWA to help familiarize State Highway Agencies with PPCP technology through the construction of demonstration projects in various states. All aspects of the Missouri demonstration project are presented, including the design, panel fabrication, pavement construction, and performance and condition during the first year in service. An evaluation of each of these aspects is also discussed with recommendations for future projects.

This report from the second Strategic Highway Research Program (SHRP 2), which is administered by the Transportation Research Board of the National Academies, provides guidance on the design, fabrication, construction, and maintenance of precast concrete pavement (PCP) systems. It includes an assessment of the state of the practice for PCP technology as well as guidelines for pavement selection, the decision-making process, and model specifications for PCP systems.

Precast prestressed concrete pavement (PPCP) is the product of an optimization of conventional materials coupled with economical fabrication and transportation means to create a product that exceeds the performance and implementation of current pavement rehabilitation methods. PPCP results in a more efficient, thinner section translating to material savings as well as improved long-term durability. Precast pavement allows faster replacement and rehabilitation of existing roadways as well as providing an economical alternative for new construction to minimize undesirable traffic congestion that causes increased fuel consumption and lost productivity. This project, near Sikeston, MO on Interstate 57, explored feasibility of current construction methods and service performance of precast roadway panels subjected to an adverse "Midwest environment" (extreme temperatures in summer accompanying deicing salts in winter). Evaluation of results from the investigation include: (a) construction challenges that may affect long term durability (b) local and global prestress distributions within PPCP (c) traffic loadings (d) daily thermal loadings (e) weekly and seasonal temperature variations and corresponding pavement behavior. Visual performance surveys over the one year long evaluation period are discussed.

Highway agencies continuously strive to expedite pavement construction and repairs and to evaluate materials and methods to provide long-lasting pavements. As part of this effort, agencies have used precast concrete slabs for more than 10 years with successive improvements in processes and systems. The Virginia Department of Transportation recently used two precast systems along with conventional cast-in-place repairs on a section of jointed reinforced concrete pavementon I-66 near Washington, D. C. One precast system, precast concrete pavement (PCP), used doweled joints. The other precast system, prestressed precast concrete pavement (PPCP), used transversely prestressed slabs post-tensioned in the longitudinal direction. Both precast systems are performing satisfactorily after 1.5 years of traffic, and the contractor was satisfied with the constructability. In multiple locations, transverse expansion joints in in PPCP were observed to be wider than the 1/2 -in widthspecified; excessively wide joints often compromise joint sealant performance, and erosion from water flowing through such joints may result in eventual loss of support over time. There were a few cracks in the PCCP section, originating mainly from grouting holes, cracks in the block-out patches, cracks and loss of epoxy at lifting hook holes, and corner breaks. There were some mid-slab cracks in the PCP slabs immediately after opening to traffic, but they are still tight and stable after 1.5 years of traffic. Even though the precast slabs initially cost more than the cast-in-place repairs to construct, the ability to construct the pavement within a short period of lane closure per day and the probability of improved quality control of plant-cast concrete warrant their use. Since this was the first application in Virginia, certain issues occurred and most were overcome, such as matching of slabs and grout leakage. The project was successfully completed and further implementation is recommended.

Precast concrete pavement (PCP) technology is gaining wider acceptance in the U.S. for rapid repair and rehabilitation of concrete pavements, as well as for reconstruction of heavily trafficked asphalt concrete intersections. Widespread use in the U.S. is fairly recent, with most projects in service less than about 14 years. Nonetheless, dozens of projects have been constructed, and advances continue to be made in all aspects of the technology, including panel design, fabrication, and installation. PCP technology is being used for intermittent repairs (both full-depth repairs and full panel replacement) and for continuous applications (longer-length/wider-area rehabilitation) with service life expectations of at least 20 years for repairs and at least 40 years for continuous applications, without significant future corrective treatment.

Load transfer restoration (LTR) is a rehabilitation technique for increasing the load transfer capability of existing jointed portland cement concrete pavement by placement of dowel bars or other mechanical devices across joints and/or cracks that exhibit poor load transfer.

To date no streamlined user efficient concrete roadway rehabilitation method is in practice in the United States. However, the use precast pavement is being evaluated and successful projects in Georgetown, Texas, El Monte, California, and most recently Charleston, Missouri are paving the way for the use of prestressed precast concrete pavement. The use of prestressed precast concrete pavement for the replacement of damaged roadways gives contractors and designers significant advantage by decreasing construction time, improving pavement performance, and mitigating user cost. The project in Charleston, Missouri, funded by the FHWA and MoDOT, is the focus of this thesis. A total of 101 panels were cast and seven were instrumented to monitor temperature and strain. The objectives set forth were to understand important properties of the materials used, study losses due to creep and shrinkage of precast pavement panels, and develop pre and post-tension loss prediction models and compare them to actual values measured in the pavement. Concurrent works by Cody Dailey and Grant Luckenbill examine early age performance of the precast panels and analyze strains relating to daily thermal gradients, seasonal trends, and traffic.