Two experimental post-tensioned pavements were completed in 1971. One purpose was to evaluate methods of construction. Another major purpose was to instrument the pavement sections and observe length changes, warping and curling in slabs up to 760 feet long, and frictional and flexural restraint in the slabs. Although some design information was already available on load carrying capacity and some other aspects of prestressed or post-tensioned pavements, additional information has been needed to develop practical and economical placement procedures and jointing details. The first experiment pavement built was an interchange ramp near Milford, Delaware completed in July 1971. It had the following characteristics: four inch subbase of cement modified soil, plastic encased prestressing steel tendon set by hand 28 inches on centers on #4 transverse bars supported on chairs 30 inches on centers, two layers of four-mil polyethylene, post-tensioning completed at 30 hours, and prestress of 214 psi in slab at the ends. Two years later these was no evidence of distress. A second section of experimental pavement 3,200 feet long was built at Dulls Airport in December 1971 using essentially the same system on a larger scale. As of two years later, no sign of distress was found.