Can someone tell me why rebar isn’t more often cathodically protected with electric current? I don’t think much power is required to resist corrosion, and it shouldn’t be too hard to test for electric continuity in the field.
Cost. This may not be cheap.
Rebar is often part of a structure’s electrical ground. Any protective current supplied might end up exiting through other connected grounds and doing little good.
How do you do this on a bridge? The rebar is one electrode. Where’s the other?
Even if you get it working, I would be a bit nervous about the reaction products. If there’s any current flow, then something is being reduced. If the medium is moist concrete, then it might well be water that gets reduced to hydrogen gas and hydroxide ions. The hydroxide ions may be harmless, but the hydrogen could be problematic.
Now you need to handle liquids and electricity and your process is not as continuous.