Will Rebar continue to corrode once the water intrusion has been stopp 2

[condohelper]

thread338-121606 by SEETWO a few years ago:

I would like to know what SEETWO did about his problem.

We have a parking garage under a condominium that has water intrusion. The 40 year old waterproofing layer between the 4" protective slab and the structural slab has given out in a number of places. Only one area has exposed rebar. We plan to remove the topping slab and install a new waterproofing system.

We were advised to test for chloride content in the slab. There is virtually no exposure to salt.

Q: Can we reasonably expect the corrosion to stop, or slow to a crawl once the water proofing is installed?

Thanks

 

[Metalguy]

Yes, if you truly prevent water from reaching the rebar, and if previous water has evaporated. Water is required for such corrosion, and wet chlorides greatly increase corrosion rates, even in cases where the proper amount of Portland cement ($$) was included in the concrete mix. Cement raises the pH to the point where non-chloride water will not cause rusting.

"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein

 

[EdStainless]

There are even additives used to keep the pH high.
In practical terms the corrosion will slow but not stop. There is always moisture in concrete and the amount will vary by season.
If spalling has not started then you should be OK.

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