Selected Answers

From Glenn Summers of ConselcoR, Inc. on March 5, 2012:
I use a penetrating sealer that forms a solid with ...read more 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.

From James Albertoni of CA Department of Water Resources on March 5, 2012:

     The high alkalinity/pH ...read more

     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.

From Jim Haig of UQMP on March 8, 2012:
I agree, James. The only additional comments I cou ...read more 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.