March 5 - March 11, 2012
What’s the best way to prevent corrosion of reinforcing bar in concrete?
Glenn Summers of ConselcoR, Inc. on
March 5, 2012:
I use a penetrating sealer that forms a solid within the gel-pore/capillary system of the matrix. This results in a No/Low moisture oxygen content interior. This material applied to the concrete surface prevents carbonation which lowers the pH. By maintaining the high pH passivating layer on the embedded steel, corrosion does not occur. The ideal application is on new concrete, as soon as possible; however, an aged concrete also benefits with a low R/H interior.
James Albertoni of CA Department of Water Resources on
March 5, 2012:
The high alkalinity/pH in the concrete will naturally passivate the steel reinforcing bar, thereby mitigating corrosion. So under normal circumstances, the reinforcing bars do not need any corrosion prevention.
If the concrete is in a highly corrosive environment such as seawater, high chloride area, or chemical containment, there are a few additional corrosion protection measures that can be utilized. The reinforcing bars can be cathodically protected or epoxy- coated. Additionally, a thicker concrete cover could be used or a coating can be applied to the concrete.
Jim Haig of UniQuest on
March 8, 2012:
Please sign in to submit your answer this question
I agree, James. The only additional comments I could make are to ensure that the correct cement and concrete formulation is used (e.g., use of sulfate-resistant cement where appropriate) and that the concrete is placed with the specified cover and compaction and consolidation. Porous concrete will be less resistant to environmental factors. In short, effort spent in ensuring the protective concrete is A1 will save potentially huge maintenance expenses later when the rebar begins to corrode and the concrete spalls.
Current PSF Question
| Submit a PSF Question
| Full PSF Archive