Design and fabrication of a compact specimen for evaluation of corrosion resistance of new post-tensioning systems

Ahern, Michael Ericson
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This thesis focuses on the design and fabrication of a new compact research specimen for evaluation of corrosion resistance of potentially improved post-tensioning systems. The development of new post-tensioning materials and systems in recent years has made some of the durability research in this area obsolete. The current research is evaluating the corrosion resistance of both existing and potential post-tensioning materials as well as examining construction practices for the new systems. The new post-tensioning systems being investigated include combinations of strand, duct (with and without couplers), bearing plates and electrical isolation. Possible combinations of the following materials were identified using a specimen matrix: Strands: Conventional, Copper Clad, Stainless Clad, Stainless, Epoxy Coated, Hot Dip Galvanized, Electroplated Galvanized; Ducts: One-Way Ribbed Plastic (with Slip-On and Snap-On Couplers), Two-Way Ribbed Plastic (with Slip-On Couplers), Galvanized Corrugated Steel (No Couplers); Bearing Plates: Non-Galvanized, Galvanized; Electrical Isolation: Conventional Tendons, Electrically Isolated Tendons. The experimental program includes both long-term exposure tests and accelerated corrosion tests. The long-term program is modeled after previous post-tensioning durability research at the University of Texas under Project 1405. To provide continuity between the two projects and comparable results, this research used construction practices, exposure methods and monitoring conditions similar to those used in the previous research, with the exception that the current specimen uses only one-eighth of the materials used in previous specimens. The compact specimens should yield data fully comparable to that from the larger specimens of the previous project. The accelerated testing of the materials and evaluation of construction practices will be completed in ongoing phases of the project