A research program utilizing modified macrocell corrosion specimens was conducted to investigate corrosion protection for internal tendons in segmental bridges. Test variables were segmental joint type, duct type, joint precompression and grout type. Specimens were subjected to 41/2 years of exposure testing, after which selected specimens were removed for destructive examination. Dry joint specimens performed very poorly, as evidenced by corrosion currents measured during exposure testing and by tendon and duct corrosion observed upon destructive examination. Epoxy joints limited chloride penetration, preventing tendon corrosion and reducing duct corrosion. Plastic post-tensioning ducts performed very well, limiting strand corrosion to negligible levels. The research indicates that epoxy joints are required for the protection of internal tendons in aggressive environments, and that plastic post-tensioning ducts provide a significant improvement in tendon corrosion protection. Many of the conclusions and recommendations presented are not only specific to segmental construction but are applicable to all forms of internal, grouted post-tensioning tendons.
