Grout mix at tank wall bottom

[NADOR123]

Hi everyone,

I am reviewing a concrete mix for tanks walls and the contractor proposing to pour grout mix at the bottom of the tank walls to avoid separation and honeycomb at the bottom of the walls. The grout mix consists of Portland cement, sand, water and admixture (Glenium 3030).
I would like to know the disadvantage of using the grout mix before pouring the concrete and is it really good engineering practice to allow using it.

Thank you for your kind help

 

[JedClampett]

We require a 2 inch grout layer around the bottom of wall joints. It's meant to prevent big aggregate from deforming the waterstop, to provide a rich mix at the base, a cushion for the main concrete pour and probably some other reasons. I've seen it left off and had decent results and I've had field engineers put it back when I had removed it. It's somewhat unlikely you're going to get a pretty layer of grout evenly distributed, but it's been in our details for a very long time, so there must be merit to it.
If the contractor is pushing for it, I'd let them use it.