Approach to Determine Corrosion Propensity in Post-Tensioned Tendons with Deficient Grout
- 1 CONCORR Florida, Inc., Merritt Island, USA
- 2 Florida International University, Miami, USA
- 3 Florida Department of Transportation, Gainesville, USA
- 4 Florida Department of Transportation, Gainesville, USA
- 5 University of North Florida, Jacksonville, USA
Abstract
After corrosion failure of post-tensioned tendons was identified in a Florida bridge in early 2011, laboratory tests were conducted in this study on extracted sections from the failed tendons to identify the grout properties and makeup leading to the failure and also to elucidate the mechanism of corrosion. The initial steps in identification of PT tendons with a high propensity for corrosion initiation or damaged included a detailed visual inspection and identification of voids in the grout. Voids in tendon can be a result of bleed water formation or construction problems. General characteristics of the deficient grout and corrosion behavior of steel in the affected bridge gave a first approach to assessing grout deficiency and corrosion susceptibility. However, refinements in the understanding of the mechanisms causing grout segregation and the elucidation of the role of sulfates, oxygen content, and pore water pH in corrosion development are required.
- A. Sagues, R. Powers and H. Wang, “Mechanism of Corrosion of Steel in Post Tensioned Grouted Assemblies,” NACE Corrosion, Houston, 2003.
- W. Hartt and S. Venugopalan, “Corrosion Evaluation of Post-Tensioned Tendons on the Mid Bay Bridge in Destin, FL.,” Florida Department of Transportation Research Center, Tallahassee, 2002.
- Corven Engineering Inc., “New Directions for Florida Post-Tensioned Bridges,” Florida Department of Transportation, Tallahassee, 2002.
- K. Lau, I. Lasa, M. Paredes and J. C. Rafols, “Laboratory Corrosion Assessment of Post-Tensioned Tendons Repaired with Dissimilar Grout,” NACE Corrosion, Houston, 2013.
- D. Trejo, S. B. Im, R. G. Pillai, M. B. D. Hueste, P. Gardoni, S. Hurlebaus and M. Gamble, “Effect of Voids in Grouted Post-Tesioned Concrete Bridge Construction: Inspection and Repair Manual for External Tendons in Segmental, Post-Tensioned Bridges,” Texas Transportation Institute, Austin, 2009.
- J. C. Rafols, “Corrosion of Post-Tensioned Tendons Repaired with Dissimilar Grout,” Unplublished Master’s Thesis, University of North Florida, Jacksonville, 2012.
- M. M. Sprinkel, “Varina Enon Tendon Failure,” Virginia Transportation Research Council, Charlottesville, 2009.
- M. Eriksson, M. Friederich and C. Vorschulze, “Variations in the Rheology and Penetrability of Cement-Based Grouts—An Experimental Study,” Cement and Concrete Research, Vol. 34, No. 7, 2004, pp. 1111-1119. doi:10.1016/j.cemconres.2003.11.023
- K. Lau and A. Sagues, “Coating Conditions Evaluation of Epoxy Coated Rebars,” ECS Transactions, Vol. 3, No. 13, 2007, pp. 81-92. doi:10.1149/1.2721432
- K. Lau, M. Paredes and J. C. Rafols, “Corrosion Evaluation of Post-Tensioned Tendons with Dissimillar Grout,” NACE Corrosion, Salt Lake City, 2012.
- A. Bentur, S. Diamond and N. Berke, “Steel Corrosion in Concrete, Fundametals and Civil Engineering Practice,” E & FN Spon, London, 1997.
- R. Barneyback and S. Diamond, “Expression and Analysis of Pore Fluids from Hardened Cement Pastes and Mortars,” Cement and Concrete Research, Vol. 11, No. 2, 1981, pp. 279-285. doi:10.1016/0008-8846(81)90069-7
- L. Li, J. Nam and W. H. Hartt, “Ex Situ Leaching Measurement of Concrete Alkalinity,” Cement and Concrete Research, 2004, pp. 1-7.
- Corven Engineering, Inc., “Mid-Bay Bridge Post-Tensioning Evaluation,” Florida Department of Transportation, Tallahassee, 2001.