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Abstract

There is disclosed a method and apparatus for the corrosion condition evaluation of unbonded prestressing elements in post-tension concrete structures. The method involves locating a prestressing element in the structure and providing at least two openings in the structure at positions along the length of the element. One of the openings is an inlet port and the other is an outlet port, each of the ports permitting communication with the gaseous environment within a conduit surrounding the prostressing element. The gaseous environment is accessed through the outlet port by extracting a sample of gas therethrough. The sample is then measured to determine its humidity and thereby evaluate the corrosion condition of the prestressing element between the inlet port and the outlet port. A method and apparatus is also provided for the on-site corrosion protection of unbonded prestressing elements whereby the gaseous environments within the conduits are cyclically pressurized with a dry gas. The protection method may also include programmable control of the dry gas pressurization and feedback of the humidity levels in the conduits for adjusting the parameters of cyclical pressurization so as to maintain a predetermined maximum humidity value in the gaseous environments associated with the prestressing elements of the structure.

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First Claim