An Investigation of Corrosion Mitigation Strategies for Aging Post Tensioned Cables

Abstract : Over the past fifty years, the U. S. Army Corps of Engineers has been upgrading its projects by installing high-capacity, post-tensioned foundation anchors. These anchors are typically made with seven-wire strand cables. The purpose of these anchors has been to achieve structural stability for Corps hydraulic concrete structures (e.g., locks, dams, approach walls) and/or to remediate cracked concrete monoliths. Substantial improvements have been made in methods to protect multistrand anchor systems from corrosion since they were first used in Corps projects more than 50 years ago, but the corrosion of older multistrand anchorage systems is still a major concern. Previous technical reports from this ERDC research team have discussed ways to measure and assess corrosion and capacity losses due to corrosion of multistrand cables used for these anchor systems, as well as perform statistical estimates and predictions of the reduced cable capacity. This technical report explores state-of-the art existing corrosion mitigation and repair techniques that are applied in other systems, and turns a critical eye toward how these techniques could be applied for anchors supporting the Corps mass concrete hydraulic structures. Ten techniques were examined and the pros and cons of these methods, with respect to the Corps structure environment, are discussed.