Rebar corrosion is probably associated to chloride exposure, carbonation, or leaking joints

https://arthurcuiu787.zenbloomer.com/posts/commercial-concrete-repair-selecting-materials-for-chemical-exposure-zones

Rebar corrosion is more commonly related to chloride exposure, carbonation, or leaking joints. Early comparison can assist no matter if full rebar paintings or special patching is wanted.