Type V Cement with Xypex

[derecha1]

I am looking for help with a concrete mix we are proposing. We are adding Xypex (a crystalline waterproofing admix) to a Type V cement concrete mix for a water storage tank. The purpose for the Type V is that the soils in the area are high in sulfates. I am hearing the the combination of Xypex and the Type V cement may not work well together.

There have been some suggestions to use Type I/II with 20-25% fly ash replacement in place of Type V. This should do the job to resist sulfate attack.

Any experience or suggestions would be helpful.

 

[KBadger]

Personally, I think the use of Xypex for a water storage tank is overkill. We specify a concrete mix with 25% fly ash replacement and a maximum 0.41 w/(c+p) ratio. This mix is, for all practical purposes, impermeable. I feel Xypex is best used in areas where you are concerned with chloride infiltration. You don't need Xypex to waterproof your tank. I should clarify that almost all the tanks we design and post-tensioned which helps control (really eliminate) cracking.