Title:
Corrosion Resistance of Unbonded Post-Tensioning Tendons with Construction Defects (Prepublished)
Author(s):
In-Seok Yoon, Hyeongyeop Shin, and Thomas H.-K. Kang
Publication:
Structural Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
construction defects; corrosion resistance; electrochemical method; grouted extruded-strand (GES) tendon; HDPE sheath; unbonded post-tensioning
DOI:
10.14359/51746823
Date:
5/15/2025
Abstract:
Corrosion of prestressing steel can threaten the durability of prestressed concrete. To ensure the durability of unbonded post-tensioning (PT) systems, it is crucial to investigate the effects of construction defects such as grease leakage and high-density polyethylene (HDPE) sheath damage. This study quantified the thickness of grease coating (PT-coating) and HDPE sheath damage as experimental variables. An accelerated corrosion test was conducted in two environments: 1) chloride ions only (Cl-) and 2) both chloride ions and dissolved oxygen (Cl- + DO). The corrosion current density and weight loss of prestressing strands and the suspended concentration density of corrosion cell solution were measured to quantify the corrosion performance. Increasing the grease coating thickness over 0.3 mm (0.012 in.) did not significantly enhance corrosion resistance. Realistic levels of HDPE sheath damage had no significant detrimental effects on durability; however, excessive HDPE sheath area loss must be avoided for long-term durability. It was examined to quantify the interrelationship between three data: electrochemical measurement, weight loss, and suspended concentration density as quantitative corrosion data. The findings of this study can serve as a basis for developing durability-related provisions, as well as controlling the construction defects of unbonded PT systems in field applications.