PRESTRESSED PAVEMENT DEMONSTRATION PROJECT

This report describes the installation of the first full-scale prestressed concrete pavement in Pennsylvania. A detailed account of the construction and placement methods used and pertinent cost data are included. The purpose of this project was to employ pavement prestressing techniques on a production basis. A variety of construction problems encountered provided valuable experience as to what can be expected on future projects of this nature. Some 23 post-tensioned slabs were placed on the main line, each with a nominal length of 600 ft (183 m). The concrete was placed with a slipform paver that also guided the prestressing strands into the pavement by feeding them through metal tubes on the paving equipment. A unique method was used to construct the joints where the slabs meet. During paving, a 3-ft (0.9-m) jacking space was provided between slabs. This space was later filled with concrete, which was prestressed by transferring the load from the strand anchors through the joint concrete. The slab ends were keyed together with an interlocking beam system to prevent faulting at the joints. Paving work was completed in December 1973. The riding quality over the pavement joints is rated as excellent. The joints are functioning well and are providing for slab length changes caused by temperature variations. The project is being closely observed and its seviceabilty will be documented in future reports.