A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Evaluation and Mitigation of Post-Tensioned Steel Corrosion
Many well documented failures of post-tensioned (PT) strands have occurred and the potential seriousness of corrosion induced failures of PT is well recognized. This paper presents two non-destructive methods for investigating corrosion of post-tensioned structures. Also discussed are methods of mitigating corrosion and extending the service life of in situ post-tensioned tendons. The principal causes of corrosion of un-bonded (un-grouted) or bonded (grouted) high strength PT tendons is the presence of moisture (high humidity), voids, air (oxygen) contamination, and the presence of corrosive constituents adjacent to the PT steel. Moisture infiltration can occur during initial construction or from water leakage. Voids can result from poor quality grouting. Early identification and mitigation of corrosive conditions significantly reduces the cost of repairs and the risk of failure. Un-bonded PT cables are used primarily in parking and other commercial structures. The first section of the paper describes an effective method for identifying the corrosion potential of un-bonded PT cables. Methods to mitigate corrosion in un-grouted PT cables are then discussed. Problems with grouting techniques and grout materials used on thousands of bridges have resulted in voids, chloride contamination, and soft grout which has resulted in premature corrosion failure of bonded PT tendons. This portion of the paper describes the use of state-of-the-art nondestructive testing methods and an innovative corrosion mitigation technique specifically developed for grouted PT tendons. Field demonstrations and case histories confirming the effectiveness of these evaluation and corrosion mitigation methods are presented.
Evaluation and Mitigation of Post-Tensioned Steel Corrosion
Many well documented failures of post-tensioned (PT) strands have occurred and the potential seriousness of corrosion induced failures of PT is well recognized. This paper presents two non-destructive methods for investigating corrosion of post-tensioned structures. Also discussed are methods of mitigating corrosion and extending the service life of in situ post-tensioned tendons. The principal causes of corrosion of un-bonded (un-grouted) or bonded (grouted) high strength PT tendons is the presence of moisture (high humidity), voids, air (oxygen) contamination, and the presence of corrosive constituents adjacent to the PT steel. Moisture infiltration can occur during initial construction or from water leakage. Voids can result from poor quality grouting. Early identification and mitigation of corrosive conditions significantly reduces the cost of repairs and the risk of failure. Un-bonded PT cables are used primarily in parking and other commercial structures. The first section of the paper describes an effective method for identifying the corrosion potential of un-bonded PT cables. Methods to mitigate corrosion in un-grouted PT cables are then discussed. Problems with grouting techniques and grout materials used on thousands of bridges have resulted in voids, chloride contamination, and soft grout which has resulted in premature corrosion failure of bonded PT tendons. This portion of the paper describes the use of state-of-the-art nondestructive testing methods and an innovative corrosion mitigation technique specifically developed for grouted PT tendons. Field demonstrations and case histories confirming the effectiveness of these evaluation and corrosion mitigation methods are presented.
Evaluation and Mitigation of Post-Tensioned Steel Corrosion
Whitmore, David (author) / Arnesen, Tore (author)
Eighth Congress on Forensic Engineering ; 2018 ; Austin, Texas
Forensic Engineering 2018 ; 879-892
2018-11-27
Conference paper
Electronic Resource
English
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