Fky ash concrete for potable water containment

[Loki]

Are there any concerns with the use of fly ash in concrete for a tank that will be storing potable water? We have a project that is trying to be as "green" as possible and would like to use a high fly ash content in the concrete. Knowing that fly ash -even that rated as non-hazardous- can contain high levels of heavy metals, I wonder if there is a possibility of heavy metals leaching into the water over time?

We are doing a renovation to a large storage tank, about 60 years old, that is likely to be in service at least another 60 years and I don't want to take chances.

Thanks!

Susan

 

[renko]

Have you considered Ground Granulated Blastfurnace Slag (GGBS). It's currently a better product in the UK and can replace more of the Ordinary cement in the mix. Both PFA (fly ash) and GGBS are accepted by the British Code BS8007.

 

[LittleWheels]

Flyash has been a standard component of concrete for potable water reservoirs here for decades.

 

[JedClampett]

Any heavy metals, which are pretty miniscule, are locked in the cement matrix and can't leach out.

 

[JStephen]

Generally coatings for potable water are certified by NSF in the US. I don't know if they've ever gotten into certifying concrete or not.