Title: Linear Polarization Resistance Tests on Corrosion Protection Degree of Post-Tensioning Grouts

Author(s): Alexandre R. Pacheco, Andrea J. Schokker, Jeffery S. Volz, and H. R. (Trey) Hamilton III

Publication: Materials Journal

Volume: 108

Issue: 4

Appears on pages(s): 365-370

Keywords: accelerated corrosion test; electrochemical tests; linear polarization resistance; post-tensioning grouts; prestressed concrete

DOI: 10.14359/51683107

Date: 7/1/2011

Abstract:
The current industry practice for acceptance testing of post-tensioning grouts includes an accelerated corrosion test (ACT), as recommended in Post-Tensioning Institute (PTI) M55.1-03, “Specification for Grouting of Post-Tensioned Structures.” The most significant downside of the current ACT method is the length of time required to run the test, which typically ranges from 1 to 2 months to complete. The linear polarization resistance (LPR) technique, on the other hand, requires only a few hours to complete; and the research presented in this paper indicates a strong correlation between the time to corrosion, as measured by the ACT method, and the system polarization resistance, as measured by the LPR technique. Based on the test results to date, the authors recommend the use of the LPR method as a prescreen for very high-quality grouts so that lengthy ACT testing is not necessary.