Fernando:
If the chlorides have already penetrated to the depth of the reinforcing, there is little you can do other than use the galvanic protection.
I found an ASCE paper (http://ascelibrary.org/doi/10.1061/%28ASCE%29MT.1943-5533.0000163) that you may wish to take a look at that talks about surface treatments. It implies that once the chlorides get in, they are in to stay.
I have heard of a Sika product FerroGard 908 that is supposed to help in these situations but have never used it. It may make sense to include it in the repair scheme if it fits within the Owner's budget. Perhaps the combination of galvanic protection and this Sika project will increase the service life enough to satisfy the Owner.
The Owner will need to adopt a maintenance cycle that repaints the building more often to keep the moisture penetration down after your repairs are complete.
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Andrew Stouppe P.E., S.E., M.ASCE
Struktura Engineers
Kaneohe HI
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Original Message:
Sent: 02-22-2017 10:59
From: Fernando Martinez
Subject: Using surface applied corrosion inhibitor for reducing corrosion rate
Hi Everyone,
I have a retrofit project of a 100-year old concrete building which is severely affected by corrosion. Samples of the concrete showed carbonation has occurred and a water-soluble chloride ion (Cl-) content higher than 1% by weight of cement. Could you please comment on the efficacy of using surface applied corrosion inhibitor for reducing corrosion rate throughout the building? I am embedding galvanic anodes at locations with structural repairs. Most of the building consists of 8” thick walls with one layer of reinforcement in the middle.
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Fernando Martinez EI, A.M.ASCE
Douglas Wood Associates
Coral Gables FL
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