X-Ray Chemical Corrosion in Reinf Conc

[CantBeam]

I have a reinforced concrete building (1968) that I am adding some medical equipment to. During site investigation I found some severe corrosion on the floor structure that I am loading. The maintenance person said that there used to be a x-ray chemical lab above and the chemicals spilled and caused the damage. My initial thought was to reinforce the area but I have considered that a chemical reaction is still occurring and I possibly need to neutralize the corrosion first.

Has anyone come across this before?
Does anyone know the chemicals used in x-ray developers and fixers? (below is the best I could find so far)
Is neutralization necessary?
Is it possible that the chemicals have absorbed into the concrete and corroded beyond what is visible?


Developer contains:
Hydroquinone
Sodium Sulfite
Potassium Hydroxide
Water

Fixer contains:
Ammonium Thiosulfite
Acetic Acid
Aluminum Sulfate

 

[brimmer]

I have dealt with corrosion of reinforced concrete in oil and gas industry. In my experience most likely corrosion will continue on the rebar once it starts, even if you repair the top. So the repaired area above would continiue to crack and spall as the corrosion products build up underneath. It would be useful now to try and find the extent of the corrosion and where the chemicals have leached into the concrete otherwise you will probably be reparing the same area into the future.

 

[hokie66]

Based on the one photograph attached, the damage is quite severe. I suggest that you retain the services of an engineer experienced in assessment and repair of concrete structures.

 

[TomDOT]

I would put the first suspicion on acid used in the "stop bath" plus general moisture.

Rebar in concrete relies primarily on the alkalinity of the concrete to prevent corrosion. Absence of water and salts (primarily chlorides) is also important.

Acid neutralizes the alkalinity in the concrete, rebar corrodes. Frequent moisture will leach alkalinity out of the concrete, and leave white accretions on the surface (effloresence) - As a secondary effect, this also exposes the alkaline components more directly to carbon dioxide in the air, which also neutralizes alkalinity (carbonation.) Again we have reduced alkalinity and easier corrosion.

Have a concrete expert look at it.