Findings of Petrographic Investigations of Embedded Cyclinder PrestressedConcrete Pipe

摘要

The Bureau of Reclamation conducted petrographic investigations to: (1) develop amethod for obtaining intact cross-sectional samples of embedded cylinder prestressed concrete pipe wall constituents, including the mortar coating, portland cement slurry, prestressing wire, and concrete pipe core suitable for subsequent thin section preparation; and (2) document the prestressing wire environment revealed by the intact sample. The examination documented the prestressing wire environment and revealed that, should moisture become available to pH concentration corrosion cells, whether from an internal or external (environment) source subsequent to pipe installation, the line corrosion noted here can only be expected to continue or possibly even accelerate. The result of continued or accelerated line corrosion could include: fractured prestressing wire, delaminated mortar, and the possibility for a potentially catastrophic pipe failure.