Assessment of Post-Tensioned Grout Durability by Accelerated Robustness and Corrosion Testing
The corrosion of steel in post-tensioned tendons has been associated with deficient grout materials containing high free sulfate ion concentrations. In a Florida bridge in 2011, tendon corrosion failures occurred for a prepackaged thixotropic grout that had developed material segregation. However, t...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-11-01
|
| Series: | Construction Materials |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2673-7108/3/4/29 |
| _version_ | 1797381555957530624 |
|---|---|
| author | Samanbar Permeh Kingsley Lau |
| author_facet | Samanbar Permeh Kingsley Lau |
| author_sort | Samanbar Permeh |
| collection | DOAJ |
| description | The corrosion of steel in post-tensioned tendons has been associated with deficient grout materials containing high free sulfate ion concentrations. In a Florida bridge in 2011, tendon corrosion failures occurred for a prepackaged thixotropic grout that had developed material segregation. However, the available grout and corrosion testing prescribed in material specifications, such as grout bleed water testing, was not able to identify the propensity or modality for the grout deficiencies and the associated steel corrosion that was observed in the field. It was of interest to identify corrosion testing methods that could prescribe grout resistance to segregation-related deficiencies that can form by aberrations in construction. The objectives of the work presented here included (1) characterizing the development of physical and chemical grout deficiencies due to excess mix water and water volume displacement, (2) developing small scale test methodologies that identify deficient grout, and (3) developing test methodologies to identify steel corrosion in deficient grout. The inverted-tee test (INT) and a modified incline-tube (MIT) test were assessed and both were shown to be useful to identify the robustness of grout materials to adverse mixing conditions (such as overwatering and pre-hydration) by parameters such as sulfate content, moisture content, electrical resistance, and steel corrosion behavior. It was shown that the different grout products have widely different propensities for segregation and accumulation of sulfate ions but adverse grout mixing practices promoted the development of grout deficiencies, including the accumulation of sulfate ions. Corrosion potentials of steel < −300 mV<sub>CSE</sub> developed in the deficient grout with higher sulfate concentrations. Likewise, the corrosion current density showed generally high values of >0.1 μA/cm<sup>2</sup> in the deficient grouts. The values produced from the test program here were consistent with historical data from earlier research that indicated corrosion conditions of steel in deficient grout with >0.7 mg/g sulfate, further verifying the adverse effects of elevated sulfate ion concentrations in the segregated grout. |
| first_indexed | 2024-03-08T20:53:12Z |
| format | Article |
| id | doaj.art-e253a2ad1e8441e1a6e2d9262edd0a09 |
| institution | Directory Open Access Journal |
| issn | 2673-7108 |
| language | English |
| last_indexed | 2024-03-08T20:53:12Z |
| publishDate | 2023-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Construction Materials |
| spelling | doaj.art-e253a2ad1e8441e1a6e2d9262edd0a092023-12-22T14:01:33ZengMDPI AGConstruction Materials2673-71082023-11-013444946110.3390/constrmater3040029Assessment of Post-Tensioned Grout Durability by Accelerated Robustness and Corrosion TestingSamanbar Permeh0Kingsley Lau1Department of Civil and Environmental Engineering, Florida International University, Miami, FL 33174, USADepartment of Civil and Environmental Engineering, Florida International University, Miami, FL 33174, USAThe corrosion of steel in post-tensioned tendons has been associated with deficient grout materials containing high free sulfate ion concentrations. In a Florida bridge in 2011, tendon corrosion failures occurred for a prepackaged thixotropic grout that had developed material segregation. However, the available grout and corrosion testing prescribed in material specifications, such as grout bleed water testing, was not able to identify the propensity or modality for the grout deficiencies and the associated steel corrosion that was observed in the field. It was of interest to identify corrosion testing methods that could prescribe grout resistance to segregation-related deficiencies that can form by aberrations in construction. The objectives of the work presented here included (1) characterizing the development of physical and chemical grout deficiencies due to excess mix water and water volume displacement, (2) developing small scale test methodologies that identify deficient grout, and (3) developing test methodologies to identify steel corrosion in deficient grout. The inverted-tee test (INT) and a modified incline-tube (MIT) test were assessed and both were shown to be useful to identify the robustness of grout materials to adverse mixing conditions (such as overwatering and pre-hydration) by parameters such as sulfate content, moisture content, electrical resistance, and steel corrosion behavior. It was shown that the different grout products have widely different propensities for segregation and accumulation of sulfate ions but adverse grout mixing practices promoted the development of grout deficiencies, including the accumulation of sulfate ions. Corrosion potentials of steel < −300 mV<sub>CSE</sub> developed in the deficient grout with higher sulfate concentrations. Likewise, the corrosion current density showed generally high values of >0.1 μA/cm<sup>2</sup> in the deficient grouts. The values produced from the test program here were consistent with historical data from earlier research that indicated corrosion conditions of steel in deficient grout with >0.7 mg/g sulfate, further verifying the adverse effects of elevated sulfate ion concentrations in the segregated grout.https://www.mdpi.com/2673-7108/3/4/29corrosionpost-tensioned (PT)groutaccelerated testing |
| spellingShingle | Samanbar Permeh Kingsley Lau Assessment of Post-Tensioned Grout Durability by Accelerated Robustness and Corrosion Testing Construction Materials corrosion post-tensioned (PT) grout accelerated testing |
| title | Assessment of Post-Tensioned Grout Durability by Accelerated Robustness and Corrosion Testing |
| title_full | Assessment of Post-Tensioned Grout Durability by Accelerated Robustness and Corrosion Testing |
| title_fullStr | Assessment of Post-Tensioned Grout Durability by Accelerated Robustness and Corrosion Testing |
| title_full_unstemmed | Assessment of Post-Tensioned Grout Durability by Accelerated Robustness and Corrosion Testing |
| title_short | Assessment of Post-Tensioned Grout Durability by Accelerated Robustness and Corrosion Testing |
| title_sort | assessment of post tensioned grout durability by accelerated robustness and corrosion testing |
| topic | corrosion post-tensioned (PT) grout accelerated testing |
| url | https://www.mdpi.com/2673-7108/3/4/29 |
| work_keys_str_mv | AT samanbarpermeh assessmentofposttensionedgroutdurabilitybyacceleratedrobustnessandcorrosiontesting AT kingsleylau assessmentofposttensionedgroutdurabilitybyacceleratedrobustnessandcorrosiontesting |