New Innovations in Precast Concrete Pavement

The need for rapid, long-lasting, sustainable concrete pavement rehabilitation strategies has never been greater for our ageing highway system. Work windows for pavement reconstruction and rehabilitation are often as little as 4-5 hours, limiting the options available for concrete pavement rehabilitation techniques. Recently, the California Department of Transportation (Caltrans), District 4, broke tradition from their traditional approach of concrete pavement rehabilitation by using prestressed precast concrete pavement to rehabilitate an existing concrete pavement on a very heavily travelled highway in the San Francisco Bay Area. The project incorporated a prestressed concrete pavement (PPCP) on a large scale. While the use of precast prestressed concrete pavement is not a new idea, some new innovations were incorporated into this project. These innovations included the use of two-way pretensioning (longitudinal and transverse directions), elimination of stressing pockets in the surface of the pavement, use of multi-strand post-tensioning ducts, and use of longer single-lane panels ranging in length from 5.5 to 11 m (18 to 36 ft). This paper discusses the development and deployment of precast prestressed concrete pavement technology on this project, including fabrication and installation issues, as well as challenges encountered throughout the project.