Corrosion of concrete piles

[jb66]

Does anybody know if is it necessary to use secondary protection of concrete for piles in underground water which contens 83 mg/l CO2 aggressive or if is it possible to take only resistant basic material (concrete)?
Thanks.

 

[Ron]

Are you sure you have your chemistry correct? 83 ppm of CO2 shouldn't cause any significant issue with a concrete pile.

 

[jb66]

I thing chemistry is OK, water is acid (6,1 pH), very hard and contens CO2 - I´m not sure if we use similar units - 83 mg/l in european units means 0,0083% CO2 per weight unit.

Regards jb66

 

[Ron]

jb66....yes, 83 mg/l is also 83 ppm.

Your water is weakly acidic, which generally causes long-term deterioration of cement paste. If your aggregates are carbonate (limestone or similar), then the aggregates will deteriorate as well. If the aggregates are siliceous, then not as much of a problem for them.

Generally, you might develop a thicker carbonation layer in the concrete than would be usual. Carbonation layers are less durable and weaker than the remainder of the matrix.

The amount of cover will be critical in this scenario. The cover and density of the concrete have more to do with rebar protection than other factors.

Something still doesn't ring true with your chemistry....have the water tested for pH, total carbonates, and dissolved gases. Something seems a bit incompatible in your results of high hardness and low pH.

 

[jb66]

Ron, thank you very much for your helpfull advise. At first time I´ve seen the chemistry I verified the values of acidity, hardness and dissolved gases but all were confirmed again.
It seemed to be incompatibility between acidity (weakly acid) and rather high content of CO2. I´m not chemist I have to ask in another laboratory for new analyse.

Best Regards