FIB 7: Corrugated plastic ducts for internal bonded post-tensioning

Optimum corrosion protection of post-tensioning tendons has been a priority since the beginning of this technology. The temporary ban of grouted post-tensioning tendons in the United Kingdom, from 1992-1996, has initiated a review of all aspects related to durability of post-tensioning tendons. One of the UK conclusions of this review was to require encapsulation of the post-tensioning tendons into wear-resistant and leak-tight plastic ducts to serve as an additional corrosion protection barrier. Since that time, other countries have at least partially adopted similar approaches. Designs of these plastic ducts may vary significantly between different suppliers. In addition, experience with these systems is still relatively limited. Hence, these plastic ducts cannot be standardised at this time. Therefore, the former FIP Commission 2, and now fib Commission 9 Reinforcing and Prestressing Materials and Systems, has set-up a task group to prepare a fib report on corrugated plastic ducts for internal, bonded post-tensioning. This report is written as a guide for an approval process for such plastic ducts. It shall serve readers such as authorities, and engineers as a guide on how to set-up a formal state approval process for these ducts, or at least allow them to properly assess systems offered for a specific project.