Half-cell potential mapping for corrosion risk evaluation of prestressed concrete ribbed panels from agricultural building after 20 years of service
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Kuupäev
2019
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Abstrakt
Corrosion of steel is a significant problem in prestressed concrete structures as it
decreases structural capacity and performance. In this research the 20-year-old prestressed
concrete ribbed ceiling panels (of type PNS-12) with dimensions of 6 m (length) by 1.5 m (width)
from an existing Estonian agricultural building (pigsty) are studied. The objective is to evaluate
the corrosion risk of steel reinforcement of ribbed panels by means of a indirect (non-destructive)
method and compare the results with a direct method.
The methodology consists of a) non-destructive measurements of half-cell potential and
b) comparision with actual condition of steel reinforcement after concrete removal (demolition).
Non-destructive measurements were performed on the 10 longitudinal ribs of 5 ribbed panels,
respectively. Steel half-cell potential maps were developed based on 900 measurement points
recorded by half-cell (Great Dane).
After destructive tests the ribbed panels including their longitudinal ribs were demolished and the
concrete was carefully removed. The position and condition of steel details was photographed
(direct method), which enabled the comparison with potential maps (indirect method).
The results demonstrated that in general, half-cell potential maps give a rather good indication on
the condition of corroding steel rebars with respect to intact details. Also, half-cell potential maps
were found relatively useful in estimating the corrosion risk in the studied precast ribbed panels.
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half-cell, potential mapping, corrosion risk, ribbed panels, articles